Exhibit 99.4

NI 43-101 Technical Report for the NONoperating Trona Royalty InterestS

Green River Basin, Sweetwater County, Wyoming

REPORT RSI-3802

	Prepared by
	Erik Hemstad, PE
	Susan Patton, PhD, RM-SME
	RESPEC
	660 Rood Avenue, Suite A
	Grand Junction, Colorado 81501
	UNITED STATES
	Prepared For
	Uranium Royalty Corp.
	Suite 1830, 1030 West Georgia Street
	Vancouver, British Columbia, V6E 2Y3
	CANADA
	EFFECTIVE DATE: December 31, 2025
	REPORT DATE: June 12, 2026
	Project Number C0120.25001

DATE AND SIGNATURE PAGE

I am responsible for Items 1.2, 1.4, and Items 7–12, 14, and coauthored Items 25 and 26.

I am responsible for Items 1.1, 1.3, and Items 2–6, 13, 15–24, and coauthored Items 25 and 26.

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certificate of author

I, Erik Hemstad, Professional Engineer, as a coauthor of the NI 43-101 Technical Report for the Nonoperating Trona Royalty Interests, Green River Basin, Sweetwater County, Wyoming, with an effective date of December 31, 2025 (the “Technical Report”), do hereby certify that:

Signed in Grand Junction, Colorado, June 12, 2026.

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certificate of author

I, Dr. Susan B. Patton, RM-SME, as a coauthor of the NI 43-101 Technical Report for the Nonoperating Trona Royalty Interests, Green River Basin, Sweetwater County, Wyoming, with an effective date of December 31, 2025 (the “Technical Report”), do hereby certify that:

Signed in Grand Junction, Colorado, June 12, 2026.

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TABLE OF CONTENTS

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TABLE OF CONTENTS (CONTINUED)

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TABLE OF CONTENTS (CONTINUED)

vi

LIST OF TABLES

vii

LIST OF FIGURES

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The Sweetwater Entities (SWTRE) are one of the largest landowners in the United States (U.S.) with approximately 850,000 fee surface acres in Wyoming. SWTRE mineral lease holdings encompass the world’s largest trona deposit in the Green River Basin in addition to other extensive holdings. This Technical Report (TR) presents the trona mineral rights holdings prepared for Uranium Royalty Corp. (URC) listed on the Toronto Stock Exchange and the Nasdaq Capital Market. The purpose of this TR is to support scientific and technical information disclosed by URC in connection with a proposed transaction involving its acquisition and/or combination with entities owning SWTRE.

For the purposes of this TR, the “Property” is the collection of trona mineral lease holdings within the Known Sodium-Leasing Area (KSLA) relating to the lease holdings of SWTRE. Four major operators mine trona and process soda ash within SWTRE mineral holdings: (1) WE Soda Ltd. (WE Soda) operating Westvaco and Granger operations of the trona mine and solution-mining and production facilities (WE Soda – Westvaco, WE Soda – Granger), (2) Şişecam Wyoming LLC (Şişecam) operating the Big Island trona mine and soda ash refinery (Big Island Operations), (3) American Soda LLC (American Soda) operating the American Soda trona mine and soda ash refinery American Soda Operations, and (4) Tata Chemicals (Soda Ash) Partners, LLC (Tata) operating the Alchem trona mine and soda ash refinery (Alchem Operations). Two Greenfield (previously undeveloped site) projects—Project West held by WE Soda and the Dry Creek Trona project held by Pacific Soda—also fall under SWTRE lands.

SWTRE hold royalty and related payment interests under a portfolio of sodium/trona lease, license and similar agreements in Wyoming with the four principal trona operators in the Green River Basin, which portfolio accounts for the substantial majority of SWTRE’s revenue. The royalty arrangements generally entitle SWTRE to payments based on the production, sale or transfer of soda ash, sodium mineral products and related products derived from the applicable leased lands.

Across the portfolio, the principal economic entitlement is generally an 8 percent production royalty, although several agreements include alternative calculations, minimum royalties, advance royalties, escalation provisions or most-favored/highest-comparable-rate mechanisms that may affect the royalty ultimately payable. Where applicable, portfolio estimates and projections assume application of the 8 percent production royalty. The SWTRE private sodium leases and licenses represent only approximately 50 percent of the areal coverage of aggregate total mineral lease holdings applicable to the operations, with an attributable production rate average to SWTRE of 48 percent calculated between 2011 to 2025 from historical royalty revenue statements.

Royalty payments are made through a combination of advanced royalties and production royalties. Advanced royalties are generally calculated based on past and projected soda ash production using the formulas defined in the applicable lease agreements. Depending on the lease, advance royalties may be payable annually, quarterly, or monthly at the commencement of the relevant production period. Production royalties are calculated based on actual soda ash produced and sold, net of specified deductions (typically including packaging and freight). The 8 percent royalty is applied to such net sales, and the amount payable is offset against any advance royalty previously paid for the applicable period.

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Certain leases provide for a minimum soda ash base price for purposes of calculating royalties; however, these provisions vary by agreement. Leases that require advance royalty payments also generally include caps on the amount of such advance payments. The mechanics and thresholds for minimum pricing and caps differ across the portfolio and are outlined in more detail in Item 4.1 of this report.

This TR was prepared for URC in accordance with section 9.2(2) of National Instrument (NI) 43-101 In authoring this TR, URC and the Qualified Persons (QPs) have relied on the exemption contained in NI 43-101, which exempt holders of royalty or similar interests from completing those items of NI 43-101F1 that require data verification, document inspection, or personal inspection of the Property beyond a guest visit to complete those items. This reliance is based on the fact that URC, through SWTRE, requested access to the necessary data from the applicable Sweetwater Operator and could not obtain the necessary information from the public domain. See Item 3.0 of this TR for further information.

The Property is located in Sweetwater County in southwestern Wyoming, United States, within the greater Green River Basin. The operations on the Property are situated in a well-established mining district near the town of Green River with excellent access via U.S. Interstate 80 (I-80), regional rail infrastructure, and proximity to major export corridors.

Land tenure in the area comprises a combination of federal (Bureau of Land Management [BLM]), state, and privately held mineral leases, with operators holding long-term mining rights through lease agreements and patented claims. Surface ownership is similarly mixed, and operations are conducted under established permitting frameworks administered by federal and state regulatory agencies. SWTRE are one of the largest private landowners within the Green River Basin and own, in fee, approximately 250,386 acres (101,328 hectares) of mineral rights and 206,278 acres (83,478 hectares) of overlying surface rights.

Major producing assets in the Green River Basin are controlled by leading industry participants, including WE Soda, Tata, Şişecam, and American Soda. These operators maintain integrated mining and processing facilities supported by extensive infrastructure and a long-standing operational history. SWTRE hold royalty and related payment interests under a portfolio of sodium/trona lease, licence and similar agreements on these mining operations.

The Green River Basin of southwestern Wyoming hosts the world’s largest trona deposit within the Eocene Green River Formation that was deposited in an alkaline, closed-basin lake system known as Lake Gosiute. This basin developed during the Laramide Orogeny, where surrounding uplifts created a structurally confined foreland basin that facilitated prolonged evaporite accumulation. Trona, sodium sesquicarbonate, which consists of more than 70 percent sodium carbonate, is often referred to as natural soda ash—the product of refining trona.

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Between approximately 53.5 and 48.5 million years before present (YBP), Lake Gosiute underwent cyclic climatic fluctuations coupled with prolonged subsidence, which resulted in repeated sequences of lacustrine sedimentation and evaporite formation. These processes produced laterally extensive bedded evaporites with interbeds of oil shale and marlstone rich in disseminated evaporite minerals.

The Green River Formation conformably overlies the fluvial Wasatch Formation and is overlain by the Bridger Formation, reflecting a transition from fluvial to lacustrine and back to fluvial conditions. The Green River Formation is subdivided into three members, in ascending order: Tipton Shale (early lacustrine), Wilkins Peak (hypersaline evaporitic), and Laney (waning lacustrine).

The Wilkins Peak Member is the principal economic unit and comprises interbedded carbonates, mudstones, and evaporites deposited under highly restricted conditions. This member reaches a thickness of up to approximately 1,350 feet (ft) and contains 42 identified trona beds, of which 25 are laterally continuous and economically significant. Deposition occurred within a migrating depocenter, resulting in predictable spatial variability in thickness and grade with beds exhibiting a shallow regional dip of approximately 1–3 degrees (°).

Thirteen trona beds (1–4, 12, 14–15, 17, 19–21, 24–25) are considered primary mining targets and support both conventional underground and solution-mining methods.

The Green River Basin in southwestern Wyoming hosts the world’s largest natural soda ash production complex, with multiple long-life operations extracting trona from the Wilkins Peak Member of the Green River Formation. Current production is dominated by a small number of established operators that employ conventional underground mining and solution-mining methods. The operations have the necessary mining permits and are expected to maintain their permits in good standing. A summary of operations are as follows:

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The QPs reviewed the adequacy of the information presented in this TR, including all historical drillhole information and analytical data, in addition to the historical reporting of Mineral Resources and Mineral Reserves in S-K 1300 Technical Report Summaries (TRS) for the Big Island Operations [Hollberg Professional Group, PC, 2025], Granger and Westvaco Operations [Stantec, 2022] and the Dry Creek Trona project [Yu et al., 2023].

SWTRE are a royalty holder rather than a mining operator. As a royalty holder, SWTRE cannot ascertain the full site-specific risks. The following inherent risks, among others, are associated with mining this deposit:

The trona operations have the necessary permits to mine and are expected to maintain their permits in good standing. Many of the operators are adding to, or replacing, production by using lower cost solution-mining methods, which are expected to extend their mine life.

The QPs recommend that URC gather supporting documentation as appropriate for the lease agreements in support of production and royalty payments.

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URC, a royalty company, anticipates that the material interests of SWTRE and the operations underlying those interests subject to this report will be material to its business upon completion of a proposed business combination transaction, pursuant to which URC agreed to acquire all of the vendors’ direct and indirect interests in SWTRE. Therefore, URC engaged RESPEC Company, LLC (RESPEC) to prepare this TR to satisfy its reporting obligations as a royalty company. SWTRE have a nonoperating ownership and royalty interest in the Property (as defined herein). Thus, SWTRE have limited access to information that an operator would normally have available to determine the detailed geological, operational, and financial aspects that would typically be outlined for a collection of operating mines and mills. See “3.0 Reliance on Other Experts” for additional information.

Trona mining and soda ash production in the Green River Basin began in the late-1940s, primarily by private companies over the past 70 years, with limited public disclosure. This TR depends on reliable public data sources, including regional geological datasets, permit and licensing submissions, state-disclosed mining information, and the limited public technical reports that are available, to provide the scoping level information enclosed.

URC engaged RESPEC to prepare this TR for the Property underlying the SWTRE’s portfolio of sodium/trona lease, license and similar agreements to be acquired. SWTRE operate a group of Wyoming-focused royalty and landholding private businesses headquartered in Lakewood, Colorado, United States.

The interpretations and conclusions presented in this TR are primarily based on information acquired from public record sources. Cited information is referenced in Item 27.0. Public data included the following:

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Public Mineral Resource and Mineral Reserve statements for some portions of the Property include the following:

Information provided by URC includes the following:

This TR is prepared for a royalty company on mining operations located in the U.S., thus, the customary Imperial unit system is used throughout the report. Unit weight is expressed in short tons of 2,000 pounds-mass. Unless otherwise stated, all currency is expressed as U.S. dollars (USD). A glossary of terms is included in Table 2-1.

The authors prepared this TR in accordance with the following standards and guidelines:

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In this TR, the terms “Mineral Resource,” “Measured Mineral Resource,” “Indicated Mineral Resource,” “Inferred Mineral Resource,” and “Mineral Reserve” have the meanings ascribed to those terms by the CIM Definition Standards for Mineral Resources and Mineral Reserves adopted by the Canadian Institute of Mining, Metallurgy, and Petroleum (CIM) Council, as amended [CIM, 2014].

The applicable definitions of Mineral Resources are listed as:

A mineral resource is a concentration or occurrence of solid material of economic interest in or on the Earth’s crust in such form, grade or quality and quantity that there are reasonable prospects for eventual economic extraction.

The location, quantity, grade or quality, continuity and other geological characteristics of a mineral resource are known, estimated or interpreted from specific geological evidence and knowledge, including sampling.

Mineral Resources are categorized based on levels of confidence as:

An inferred mineral resource is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling. Geological evidence is sufficient to imply but not verify geological and grade or quality continuity. An inferred mineral resource has a lower level of confidence than that applying to an Indicated mineral resource and must not be converted to a mineral reserve. It is reasonably expected that the majority of inferred mineral resources could be upgraded to indicated mineral resources with continued exploration.

An indicated mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics are estimated with sufficient confidence to allow the application of modifying factors in sufficient detail to support mine planning and evaluation of the economic viability of the deposit. Geological evidence is derived from adequately detailed and reliable exploration, sampling and testing and is sufficient to assume geological and grade or quality continuity between points of observation. An indicated mineral resource has a lower level of confidence than that applying to a measured mineral resource and may only be converted to a probable mineral reserve.

A measured mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape, and physical characteristics are estimated with confidence sufficient to allow the application of modifying factors to support detailed mine planning and final evaluation of the economic viability of the deposit. Geological evidence is derived from detailed and reliable exploration, sampling and testing and is sufficient to confirm geological and grade or quality continuity between points of observation. A measured mineral resource has a higher level of confidence than that applying to either an indicated mineral resource or an inferred mineral resource. It may be converted to a proven mineral reserve or to a probable mineral reserve.

Mineral reserves are those parts of mineral resources which, after the application of all mining factors, result in an estimated tonnage and grade which, in the opinion of the Qualified Person(s) making the estimates, is the basis of an economically viable project after taking account of all relevant modifying factors.

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Throughout this TR, industry-specific terminology for geological, technical, and sodium mineral production is commonly used. The conversion of trona to soda ash chemically defined as 2(Na₂CO₃·NaHCO₃·2H₂O) plus heat to 3Na₂CO₃ + CO₂ + 5H₂O, can be described by the molecular weight ratio of 1.4218 tons of trona for every 1 ton of soda ash at 100 percent conversion efficiency. Accounting for refining efficiencies, the conversion ratio ranges from 1.55 to 1.83 tons of trona to tons of soda ash. Table 2-1 provides a list of definitions for the most common terms and phrases.

The QPs have relied on the exemption set forth in Section 9.2(2) of NI 43-101. However, the QPs have in-depth knowledge of the operations and mineral holdings from extensive work in the Green River Basin over the last 20 years, ranging from exploration, underground design, feasibility studies, instrumentation, analysis, and due diligence for sales.

QP Susan Patton, PE, performed a site visit as a royalty interest with SWTRE representatives on February 11, 2026. The visit was hosted by Aaron Reichl of WE Soda at the Westvaco Mine and the Granger solution mine. The following key aspects were observed:

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Table 2-1. Glossary of Terms (Page 1 of 3)

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Table 2-1. Glossary of Terms (Page 2 of 3)

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Table 2-1. Glossary of Terms (Page 3 of 3)

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The authors relied on information for the mineral tenure included in Item 4.1 provided by SWTRE to the URC. The QPs did not independently verify lease sections, agreements, or mineral tenure and terms, and relied upon SWTRE- and URC-provided land opinions for the material lease sections. An updated title opinion on the material lease agreements was provided by Wolcott Land Services, dated March 24, 2026.

The authors relied on the permitting status provided in the high-level environmental assessment by MWStaub Consulting LLC [2026] for information included in Item 20.0.

In authoring this TR, URC and the QPs relied upon the exemption contained in section 9.2(2) of NI 43-101, which exempt holders of royalty or similar interests from completing those items of NI 43-101F1 that require data verification, inspection of documents, or personal inspection of the Property to complete those items. This reliance is based on the fact that URC, through SWTRE, requested that the operators provide qualified persons designated by URC with site access and underlying technical data, reports, models, and other information sufficient for the qualified persons designated by URC to prepare a full TR under NI 43-101 and enable URC to prepare disclosure of all required information under NI 43-101 relating to the Property, which information is unavailable from the public domain, and the operator denied the request. The QPs have relied on such exemption in not completing: QP site visits to each operator or project, full data verification of reported drilling results, mineral resources, mineral reserves, individual mine recoveries, mine losses, dilution, process losses, process recoveries, equipment lists, capital costs, and operational cost data.

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The operators and projects within the KSLA are listed in Table 4-1 and shown graphically in Figure 4-1. The leases are private mineral holdings that were originally granted by the U.S. government through the Pacific Railroad Act of 1864. To accelerate the construction of the Transcontinental Railroad, the Pacific Railroad Act granted every other section (nominal 640 acres) within 20 miles of the railroad to Union Pacific.

Table 4-1. Trona Operators and Projects Summary

In the Property area, the BLM designated the KSLA to protect the underground trona mines from oil-and-gas drilling within the boundary. Further within the KSLA, the BLM defined a Mechanical Mining Trona Area (MMTA) where the thickness of the trona bed exceeds 8 ft, has an in-place trona grade greater than 80 percent, contains less than 2 percent halite (NaCl), and has a maximum depth of 2,000 ft. SWTRE own in fee, approximately 250,386 acres (101,328 hectares) of mineral rights and 206,278 acres (83,478 hectares) of overlying surface rights within the KSLA.

SWTRE own their interest in the sodium leases and licenses through a 100 percent interest in Sweetwater Trona OpCo LLC and Sweetwater Surface LLC, and as a majority shareholder (52 percent) in the Uinta Development Company. SWTRE originally obtained control over this land position via the purchase of assets from Occidental Petroleum Corporation in 2020. The ownership position by Sweetwater Entities is summarized in Tables 4-2 and 4-3.

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Figure 4-1. Area Lease Map.

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Table 4-2. The Sweetwater Entities Land Ownership Within the Known Sodium-Leasing Area of the Green River Basin

A total of 250,386 acres of fee mineral interests are held by SWTRE within the KSLA of the Green River Basin, as summarized in Table -3. Within this total, SWTRE material interests are defined by 12 sodium lease and license agreements that cover approximately 108,934 acres. The lease and license agreements have been amended over time as new recovery methods are introduced and operators change.

SWTRE hold royalty and related payment interests under a portfolio of sodium lease agreements associated with five operating and two advanced Greenfield natural soda ash projects in the Green River Basin. These agreements vary in form, term, continuation provisions and payment mechanics. The royalty arrangements generally entitle SWTRE to payments based on the production, sale or transfer of soda ash, sodium mineral products and related products derived from the applicable leased lands, and certain agreements may include minimum, advance, rental, bonus, shortfall or similar payment provisions.

Across the portfolio, the principal economic entitlement is generally an 8 percent production royalty less permitted deductions (typically direct bagging and palletizing costs and freight allowances), although several agreements include alternative calculations, minimum royalties, advance royalties, escalation provisions or most-favored/highest-comparable-rate mechanisms that may affect the royalty ultimately payable. Unless otherwise noted herein, all royalties owned by SWTRE pay a royalty equal to 8 percent of the net sale price of soda ash. Royalty payments are made through a combination of advanced royalties and production royalties. Advanced royalties are generally calculated based on past and projected soda ash production, using the formulas defined in the applicable lease agreements. Depending on the lease, advanced royalties may be payable annually, quarterly, or monthly at the commencement of the relevant production period. Production royalties are calculated based on actual soda ash produced and sold, net of specified deductions (typically including packaging and freight). The 8 percent royalty fee is applied to such net sales, and the amount payable is offset against any advance royalty previously paid for the applicable period.

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Certain leases, as described in the following text, provide for a minimum base price for soda ash for purposes of calculating royalties; however, these provisions vary by agreement. Leases that require advance royalty payments also generally include caps on the amount of such advance payments. The mechanics and thresholds for minimum pricing and caps differ across the portfolio.

The underlying agreements contain confidentiality provisions restricting disclosure of detailed contractual, operational, geological, production and other information. Accordingly, the disclosure in this TR describes SWTRE’s royalty portfolio on an aggregated basis, except where more specific disclosure is necessary to provide full, true and plain disclosure of all material facts.

SWTRE royalty interest on the Granger and Westvaco operations are represented by the following:

In each case, the lease shall remain in full force and effect as long as the lessee continuously conducts operations to mine and remove sodium minerals in commercial quantities from any part or portion of the leased premises described therein. Each lease contains varying provisions for termination, generally allowing either party to terminate for uncured defaults after written notice and, in some cases, upon the lessee ceasing refining or production at its facilities.

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West Soda LLC, a subsidiary of WE Soda, is also the operator developing Project West, a new Greenfield soda ash production project. SWTRE royalty interest on Project West is represented by the following:

SWTRE royalty interest on the American Soda Operations are represented by the following:

SWTRE royalty interest on the Big Island Operations is represented by the following:

On September 20, 2010, Şişecam exercised its right to renew the 702 Lease for an additional 50-year period. The current 702 Lease extends to July 18, 2061.

SWTRE royalty interest on the Alchem Operations are represented by the following:

Each of the 739 Lease, the 703 Lease and the UDC Lease continue so long as the lessee conducts continuous operations on the leased premises.

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The operations underlying the leases are summarized in Table 4-4 and shown by lease/license number location in Figure 4-2.

Table 4-4. Sodium Mineral Product Lease and License Summary by Operator

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The operators who hold SWTRE mineral leases are required to maintain all operating permits with the WYDEQ that cover air, industrial siting, land quality, solid and hazardous waste and water quality. The mine permit issued by the LQD requires annual reporting and bonding for surface disturbance. Permit obligations of the lessee’s are further described in Item 20.0.

Figure 4-1. Detail of Leases Map.

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SWTRE are the royalty holder and not subject to back-in rights or other agreements and encumbrances. To the extent known, the operators are subject to royalty agreements on the mineral leases with private entities in addition to SWTRE, State of Wyoming leases, and federal leases managed by the BLM within their respective permit boundaries. SWTRE, as the royalty holder, have no knowledge of the royalty agreements with other private mineral leases. Failure to pay rentals on or before the lease anniversary date terminates the leases. Termination of a lease does relieve the lessee of any obligation incurred under the lease other than the obligation to pay rental or penalty.

Solid mineral leasing on state land is guided by WS 36-6-101 as well as Chapters 19–25 of the Rules and Regulations of the Board of Land Commissioners. The Office of State Lands and Investments requires lease bonding for all producing solid mineral leases.

Trona is defined by the U.S. government as a “solid leasable mineral,” subject to the Mineral Leasing Act of 1920. Federally owned sodium resources are controlled by the Department of the Interior and managed by the BLM and limited by Title 30§184(b). The act stipulates 10-year renewable lease periods, subject to annual rental and royalty fees, and demonstrated diligence. The federal government limits sodium leases to 5,120 acres by any one operator in one state but an exception in 30§184(b)(2) allows the Secretary, at their discretion, sodium leases or permits on up to 30,720 acres in any one state. The federal trona lease royalty rate is nominally 6 percent. As of January 1, 2021, all BLM trona leases have a 2 percent royalty rate for a period of 10 years, based on Industry-Wide Royalty Reduction Soda Ash and Sodium Bicarbonate issued by the Secretary of the Interior, for all existing and future federal soda ash or sodium bicarbonate leases [43 CFR 3504.21].

As a royalty holder, SWTRE are not subject to the environmental liabilities of the Operators. The QP is unaware of any environmental liabilities to which the Property is subject, other than the normal federal and state licensing and permitting requirements or restrictions as further detailed in Item 20.0. Each mine permit carries a reclamation bond appropriate for the anticipated closure costs.

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The mineral lease holdings of SWTRE contained within the KSLA in Wyoming’s Green River Basin span an area approximately 19 miles east to west and 32 miles north to south. The Green River Basin itself is contained within the southwestern quarter of Wyoming, a vast landscape characteristic of a high desert environment. The basin is bounded by the Wind River Range to the north, the Sevier overthrust belt to the west, the Rawlins uplift to the east, and the Uinta Mountains to the south. The Rock Springs uplift is a central, elongated uplift that extends north to south, truncating the northeastern extent of trona mineralization. Several other prominent buttes, mesas, arroyos, and moderate canyons serve to break up the broader arid plains and hills. The basin generally slopes to the south, and surface elevations range from 6,000 to 9,500 ft above sea level (ASL). Higher elevations are found along most basin margins where foothills rise to meet bounding structural features.

The Green River is the primary drainage and originates in the Wind River Range. Many notable tributaries feed the Green River, including New Fork River, Big Sandy River, Fontenelle Creek, Blacks Fork River, and La Barge Creek. The basin’s lowest elevation occurs at Flaming Gorge Reservoir, where the Green River collects before spilling into Utah and flowing south. Sagebrush, greasewood, bunch grass, and other low desert plants dominate the broad, rolling plains. Cottonwood, willows, and scattered coniferous trees flank many of the perennial and intermittent drainages.

I-80 is a divided four-lane highway that generally bisects the area into northern and southern halves. I-80 provides access to Rawlins, Wyoming; Cheyenne, Wyoming; and Denver, Colorado (indirectly) to the east, and Salt Lake City, Utah, to the west. Several state highways maintained by the Wyoming Department of Transportation and paved two-lane roads maintained by Sweetwater County broadly provide general access across the area. Green River (population of 11,825 [Data USA, 2024a]) and Rock Springs (population of 23,526, [Data USA, 2024b]) are the two population centers in the Green River Basin. Green River lies just east of the KSLA, and Rock Springs is 15 miles further east. Salt Lake City (population of 204,000) is the nearest major metropolitan area and is 194 miles west of the Property. The broader Salt Lake City metro area has a population exceeding 1.2 million.

The Green River Basin is serviced by the Union Pacific Railroad. The east-west main rail line generally runs parallel to and north of I-80. Dedicated industrial spurs provide direct rail access to several trona operators. Air service primarily travels through the Southwest Wyoming Regional Airport, which is located approximately 10 miles east of Rock Springs, Wyoming.

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The high, intermontane Green River Basin has a cool, semiarid climate. Diurnal variation can be considerable, with temperatures often fluctuating 20–40 degrees Fahrenheit (°F) in a 24-hour period, especially during the dry summer months. Precipitation, and conversely aridity, vary largely on location across the Green River Basin with higher elevations around the margin typically receiving double the rainfall as the basin’s center. Figure 5-1 provides monthly high and low average temperatures, along with average monthly precipitation for the town of Green River, Wyoming. The operating season for trona producers is considered to be year-round. Extreme weather conditions, such as very high winds and occasional storms, may occur, but these events generally seldom impact mining operations.

Figure 5-1. Property Climate Averages [National Weather Service, 2026].

The Green River Basin has seen consistent trona production for over 70 years and, therefore, the mine-specific infrastructure is generally well-developed. As a royalty interest, SWTRE did not inspect the processing and refining plants but as evidenced by product sales in royalty production reports, the soda ash processing plants and refining capabilities appear to be maintained and routinely upgraded. Regional electrical power generation and distribution is sufficient and reliable. The communities of Green River and Rock Springs are well-established and provide strong mining and industrial support capabilities and workforce. Other regional and mine-specific infrastructure includes the following:

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Mountain Fuel Supply Company is credited with discovering the trona deposits in Wyoming while core drilling the John Hay #1 well in October 1937 [Wyoming State Geologic Survey, 2026]. Westvaco Chemical Corporation sunk a shaft and produced the first trona from trona Bed 17 at a depth of 1,500 ft in 1949.

The Property leases are private mineral holdings originally granted by the U.S. government under the Pacific Railroad Act of 1864. The history of SWTRE mineral lease ownership is shown in Table 6-1, and the history of the counterparties to the trona leases is shown in Table 6-2.

Table 6-1. History of Leases

Following Mountain Fuel Supply’s first trona core well, Union Pacific Railroad cored four drillholes in the basin between 1940 and 1942, with mineable thicknesses of trona encountered in each drillhole [Burnside and Culbertson, 1979]. Between 1944 and 1946, Westvaco drilled an additional three exploration wells through bed 17 before sinking its shaft for mine development. Through 1956, a total of 20 wells were drilled for trona exploration [Fahey, 1962], in addition to the Westvaco shaft.

A cooperative study between the BLM and the U. S Geological Survey [Wiig et al., 1995] evaluated the Wyoming natural sodium carbonate deposit in the Green River Basin. The study evaluated 540 boreholes of subsurface well information from the Rock Springs District BLM office beginning in 1987. The exploratory wells included oil-and-gas wells with geophysical logs and cores and assay data provided by operators holding federal sodium leases. For cores without chemical analytical data, the halite and water-insoluble material were estimated from the detailed core descriptions.

Exploration activities performed by individual operators either within their active mine workings or conducted from the surface were not available or reported within the public domain for review.

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Table 6-2. History of Operators

Trona production began in 1949 at Westvaco using conventional room-and-pillar mining methods and subsequently in 1950 for its Granger Mine. The Big Island Mine opened in 1962 and American Soda Operations followed in 1979. The trona production sourced from the Wyoming State Mine Inspectors’ annual reports from 1949 to 2024 is shown in Figure 6-1. Production ramped up over the decades as the new mines commenced operations and has held steady since the mid-1990s.

Historical Mineral Resources, reported as in situ trona, are provided in Table 6-3 and historical Mineral Reserves by operator are listed in Table 6-4. Trona, sodium sesquicarbonate comprising more than 70 percent sodium carbonate, is often referred to as natural soda ash, which is the product of refining trona.

Other operators on the Property do not have publicly filed Mineral Resources and Mineral Reserves.

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Figure 6-1. Wyoming Trona Production [State of Wyoming, 1949–2026]. Typical conversion trona to soda ash is at a ratio of 1.6:1.

Mineral Resources and Mineral Reserves for two operators are reported under Regulation S-K, Subpart 1300, which has a slightly different definition of Mineral Resources than NI 43-101. The QP concludes that for the purposes of this reporting, the CIM and Regulation S-K definitions are similar and equivalent. According to 17 Code of Federal Regulations (CFR) § 229.1301 (2021), the following definitions are included for reference:

An inferred mineral resource is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling. An inferred mineral resource has the lowest level of geological confidence of all mineral resources, which prevents the application of the modifying factors in a manner useful for evaluation of economic viability. An inferred mineral resource, therefore, may not be converted to a mineral reserve.

An indicated mineral resource is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of adequate geological evidence and sampling. An indicated mineral resource has a lower level of confidence than the level of confidence of a measured mineral resource and may only be converted to a probable mineral reserve. As used in this subpart, the term adequate geological evidence means evidence that is sufficient to establish geological and grade or quality continuity with reasonable certainty.

A measured mineral resource is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of conclusive geological evidence and sampling. As used in this subpart, the term conclusive geological evidence means evidence that is sufficient to test and confirm geological and grade or quality continuity.

A probable mineral reserve is the economically mineable part of an indicated and, in some cases, a measured mineral resource.

A proven mineral reserve is the economically mineable part of a measured mineral resource. For a proven mineral reserve, the qualified person has a high degree of confidence in the results obtained from the application of the modifying factors and in the estimates of tonnage and grade or quality. A proven mineral reserve can only result from conversion of a measured mineral resource.

26

Table 6-3. Historical Mineral Resource Estimates

Sums may not be exact because of rounding.

27

Table 6-4. Historical Mineral Reserve Estimates for the Operating Companies

Sums may not be exact because of rounding.

The previous owner and operator of WE Soda’s Granger and Westvaco Operations, Genesis Alkali Wyoming LP, stated Mineral Resources and Mineral Reserves in a TRS prepared by Stantec [2022] with an effective date of December 31, 2021, and available under Genesis Alkali Wyoming LP’s profile (www.sec.gov).

Big Island Operations Mineral Resources (exclusive of Reserves) and Mineral Reserves have previously been reported for NRP through its S-K 1300 TRS [Hollberg, 2025] with an effective date of December 31, 2024, and is available under the profile of NRP (www.sec.gov).

28

A TR was filed under NI 43-101 by Kew Soda Ltd, a former owner of the Dry Creek Trona project, with an effective date of December 31, 2022 [Yu et al., 2023] and is available via the registration documents of Kew Soda Ltd. and its filings within the United Kingdom. At the time of the reporting, Pacific Soda, a Delaware limited liability company, was owned 60 percent by Şişecam Chemicals USA Inc. and 40 percent by Imperial Natural Resources Trona Mining Inc., which is an indirect wholly owned subsidiary of WE Soda. Kew Soda Ltd. acts as a holding company of WE Soda and its subsidiaries.

The historical Mineral Resource and Mineral Reserve estimates included herein are historical in nature and a QP has not completed sufficient work to classify the historical estimate as a current Mineral Resource or Mineral Reserve. Accordingly, the QP is not treating the historical estimate as current Mineral Resources or Mineral Reserves. The QP opines that the historical Mineral Resource and Mineral Reserve estimates included herein are reliable and relevant in nature with the exception that the QP is unaware of sufficient engineering to support including bed 15 as a conventional mining target for WE Soda – Westvaco.

The Mineral Reserves for the Dry Creek Trona project as stated for the combined beds 1–4 by Yu et al. [2023] are 121.2 million metric tonnes (133.6 Mt) of TA. The categories of Proven Mineral Reserves and Probable Mineral Reserves are not stated separately. The Mineral Reserves are subject to the following:

29

The bedded trona deposits of the Green River Formation were precipitated from alkaline brines in an ancient lacustrine system referred to as Lake Gosiute. During the late-Cretaceous to early-Paleogene periods, compressional tectonism associated with the Laramide Orogeny uplifted several mountain ranges in the region. The interior space between these surrounding uplifts formed a foreland basin—an area of subsidence reflexively driven by the adjacent uplifts. This subsiding area, known as the Green River Basin, established a catchment for sedimentary deposition and became a closed drainage system with zero or very few outflows.

Lake Gosiute covered most of southwest Wyoming 53.5–48.5 million YBP. Lake fluctuations in response to tectonic activity and climatic changes resulted in a cyclic pattern of oil shale deposition, accumulation of bedded evaporites, and interbeds of marlstone and altered tuffs. The volcanic ash, which became altered tuff, was deposited by prevailing southeasterly winds from the Absaroka and Challis volcanic fields [Cupertino, 2023] in what is now northwest Wyoming and Idaho, respectively.

As illustrated in Figure 7-1, the greater Green River Basin is tectonically bounded on the west by an overthrust belt and on all other sides by Laramide uplifts, including the Wind River Range and Granite Mountains to the north; the Uinta Mountains and Axial Basin uplift to the south; and the Rawlins uplift, Sierra Madre Range, and Park Range to the east [Roehler, 1992]. Within the area, major intrabasinal anticlines and arches partition the greater Green River Basin into several structurally distinct subbasins: the Green River, Great Divide, Washakie, and Sand Wash subbasins. Other notable structures include the Rock Springs uplift, the Moxa arch and associated LaBarge platform, the Pinedale anticline, the Wamsutter arch, and the Cherokee Ridge arch [Roehler, 1992]. These features exerted strong controls on subsidence patterns, sediment thickness, and accommodation space that contributed to the development of a thick sedimentary succession, which influenced the spatial distribution of Lake Gosiute and the evaporite-bearing Green River Formation preserved within the Basin.

In a regional context, the Green River Basin is the largest subbasin within the southwestern Wyoming province boundary. Stretching approximately 160 miles from north to south and 60 miles from east to west, the Green River Basin encompasses roughly 10,500 square miles of southwestern Wyoming.

The Green River Basin is structurally bounded by the Wyoming thrust belt to the west, the Rock Springs uplift to the east, the Wind River Mountains to the north, and the Uinta Mountains to the south. Basin margins are marked by prominent hogbacks, escarpments, and pediment surfaces, including Oyster Ridge and White Mountain along the west flank of the Rock Springs uplift. Elevations vary from under 6,000 ft in basin low points to nearly 9,500 ft near the surrounding uplifts. The basin features extensive exposures of Paleogene strata from the Wasatch, Green River, and Bridger Formations, as illustrated in Figure 7-2 [Roehler, 1992].

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31

Figure 7-2. Regional Map of the Distribution of Geologic Units Within and Near the Green River Basin.

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The Green River Formation records the deposition of extensive lacustrine sediments and evaporite minerals during the early Eocene epoch within a series of intermontane basins formed during the late stages of Laramide deformation [Smith et al., 2015]. Stratigraphically, the Green River Formation overlies the Wasatch Formation and is overlain by the Bridger Formation, reflecting a basin-scale transition from dominantly fluvial to lacustrine and back to fluvial depositional. The Wasatch Formation consists primarily of fluvial channel deposits, floodplain sediments, and paleosols that were deposited contemporaneously with Green River lacustrine strata and extensively interfinger with them along basin margins, recording sediment supply from adjacent Laramide uplifts. The overlying Bridger Formation marks the cessation of widespread lacustrine activity following the disappearance of Lake Gosiute and reflects reduced accommodation, increased erosion of surrounding uplifts, and the establishment of fluvial drainage systems across the basin [Smith et al., 2015].

The Green River Formation is subdivided into three principal members that reflect changing basin hydrology and lake chemistry: (1) the Tipton Shale Member, deposited during early lake expansion under relatively fresh to mildly saline conditions; (2) the Wilkins Peak Member, representing the most restricted, hypersaline phase of Lake Gosiute and containing cyclic evaporites, including trona; and (3) the overlying Laney Member, which records a return to more open-lake and mixed lacustrine-fluvial conditions as subsidence waned [Smith et al., 2015].

The Tipton Shale Member records early lacustrine activity in the Green River Formation and is lithologically diverse, consisting primarily of calcareous mudstone and marlstone with interbeds of fossiliferous siltstone, ostracode- and oolitic-grainstone, stromatolite, and deltaic to shoreline sandstones, including the Farson Sandstone [Graf et al., 2015]. Organic-rich, micro-laminated, kerogen-bearing mudstones alternate with less organic-rich laminated or massive mudstones that reflect repeated shifts in lake depth, water chemistry, and oxygenation [Graf et al., 2015]. Carbonate mineralogy oscillates between calcite and dolomite and corresponds to changes in hydrologic openness and stratification.

The Wilkins Peak Member lies between the Tipton and the Laney Members and represents the most evaporative phase of Lake Gosiute [Smith et al., 2015]. The Wilkins Peak Member is lithologically complex and consists of interbedded lacustrine carbonates, calcareous mudstones, sandstones, and abundant evaporites, including trona and halite in basin-interior settings [Roehler, 1992]. Basin-interior strata are typically dolomitic and evaporite-rich, whereas basin-margin facies near the Uinta uplift are more calcitic and siliciclastic, reflecting strong lateral facies partitioning across the basin [Smith et al., 2015].

Deposition of the Wilkins Peak Member occurred in a structurally active, hydrologically closed basin strongly influenced by ongoing Laramide uplift [Smith et al., 2015]. The Wilkins Peak Member reaches as much as 1,350 ft in thickness in the southern basin [Wiig et al., 1995]. Temporal and spatial changes in subsidence resulted in the migration of the depositional center across the basin. Initially, the depocenter focused on the south and southeastern basin, recorded today by trona beds 1–14. Evaporite deposition then shifted to the northern areas (trona beds 14–22) before returning to the southern basin, where trona beds 22–25 are centered. Although many trona beds may occur in most locations relative to modern KSLA boundaries, understanding where the depocenter was focused during Wilkins Peak deposition aids in understanding the distribution of the thickest beds and the highest trona grades. The evaporite depocenter’s migrating behavior can be observed in the stratigraphic cross sections shown in Figures 7-3 and 7-4, with the depocenter most evident in the latter. Trona beds across the basin generally exhibit a shallow southwesterly dip of 1-3°.

The Laney Member represents the final phase of Lake Gosiute and is dominated by lacustrine mudstone and marlstone, including thick intervals of organic-rich oil shale interbedded with siltstone, stromatolite, and volcaniclastic to deltaic sandstone [Smith et al., 2015]. The lower facies of the Laney Member preserve repetitive successions of profundal oil shale and marginal carbonate rocks, whereas the upper facies record increasing siliciclastic input and delta progradation [Pietras and Carroll, 2006]. The Laney Member marks the waning stages of Eocene lacustrine deposition in the Green River Formation and the eventual replacement of Lake Gosiute by fluvial and alluvial environments [Smith et al., 2015].

The Wilkins Peak Member of the Green River Formation has been documented to contain 42 distinct trona beds. Of these, 25 are shown to possess an average thickness of at least 3.3 ft and have at least 100 square miles of contiguous extent. These 25 trona beds are conventionally numbered in ascending order, coinciding with their age and order of deposition, as shown in Figure 7-5.

Of these 25 trona beds, 13 are considered targets for mechanical and/or solution mining. These beds, in ascending order, include trona beds 1, 2, 3, 4, 12, 14, 15, 17, 19, 20, 21, 24, and 25. Descriptions of these target beds are provided in Table 7-1.

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34

35

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Table 7-1. Target Beds of the Wilkins Peak Member

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Trona (Na₃ (CO₃) (HCO₃) 2H₂O) is an evaporite mineral that precipitates in nonmarine, lacustrine, and highly saline environments. The Green River Basin of southwestern Wyoming hosts the world’s largest known occurrence of trona [Leigh, 1998]. In what is regarded as the official deposit model for trona, Orris and Bliss [1991] describe the characteristics for sodium carbonate in bedded lacustrine evaporites. The authors explicitly name the Wilkins Peak Member of the Green River Formation as hosting considerable trona resources in the forms of bedded trona and shortite (Na₂Ca₂(CO₃)₃) mineralization disseminated primarily in adjacent interbeds of marlstone and oil shale. The 25 thickest trona beds in the Wilkins Peak Member are estimated to contain 82 billion short tons of trona and an additional 53 billion short tons of mixed trona and halite.

During the middle Eocene epoch (53.5–48.5 million YPB), intermittent volcanic activity contributed abundant ash to the depositional environment of ancestral Lake Gosiute. After being aerially deposited into the large alkaline lake, the ash was altered and contributed dissolved ions to the local sediments and lake waters. Major ions in solution likely included calcium (Ca), Magnesium (Mg), sodium (Na), bicarbonate (HCO₃), sulfate (SO₄), and chloride (Cl^-). In addition to climatic chemical processes—the most notable being evaporation—biogenic processes strongly influenced the solution chemistry and composition of the lake waters from which trona minerals precipitated. The trona deposit model requires local association with soluble, alkalic rocks or detrital material before mineral precipitation.

Typical gangue materials include oil shale, shale, and marlstone. A conventionally mined trona bed commonly exhibits greater than 85 percent trona grade. Dissolution surfaces and structures are common at and near contact with marlstone or shale interbeds.

As a holder of a royalty interest, SWTRE have not conducted any exploration activities at the Property.

39

SWTRE have not conducted any drilling on the Property.

Historical drilling data were obtained from SWTRE in the form of an Excel spreadsheet-formatted database. The database comprised 984 individual drillholes and separated tabs for the collar coordinates, trona bed intervals, assay data, and orientation data. The drillhole collars information provided identifiers labeling the drillhole I.D., Easting, Northing, Elevation, and Total Depth (TD). The trona bed intervals were identified with a “from” and “to” depth and a total thickness. Information was only provided for the numbered trona beds. Interburden data along with overlying strata were not included. Assay data were provided for 860 drillholes comprising 4,136 intervals, including percent trona and 3,133 intervals containing percent NaCl. The orientation data assumed that each drillhole was completely vertical without any deviation. If available, additional drillhole files in the form of geophysical logs, lithologic logs, core photographs, and drillhole completion records were provided by SWTRE. All original source drilling information provided by SWTRE is available in the public domain through the WYOGCC.

Although robust, a collection of 860 drillholes would likely represent only a fraction of the total count because many more holes have been drilled and are not publicly available. Because of the extensive drilling history across the applicable lease holdings and the wide range of objectives and methods, thoroughly summarizing the standard equipment used or the procedures followed is not feasible. The drilling method used ultimately depends on the program’s specific objectives and the type of data needed to accomplish those objectives. Generalizations can be made, however, based on the collection of publicly available drill data previously mentioned. Exploratory holes for trona in the Green River Basin are typically drilled to depths ranging from 800 to approximately 2,200 ft because this interval hosts the trona beds targeted for production.

Each of the trona operators of the Property in the Green River Basin has conducted extensive drilling, along with several completed wells by other entities, which was primarily for oil-and-gas exploration. Following the discovery of deep-bedded trona by Mountain Fuel Supply Company while drilling for oil in 1938, an increasing number of wells were completed with the explicit purpose of delineating the vast deposit of trona. These exploratory wells follow most standard core-drilling procedures and protocols with some key exceptions. The drilling method most often used for trona exploration employs diamond-core drilling (i.e., the cylindrical bit face is impregnated with industrial diamonds in a synthetic matrix). As the drill string penetrates into the earth, a cylinder of rock protrudes up into the core barrel, where it can then be recovered and brought to the surface. Geological, chemical, and/or geotechnical parameters of the rock core sample can then be analyzed. One notable difference when drilling to recover an evaporite sample (such as trona) is the need to use a drilling fluid saturated with sodium carbonate or an additive similarly derived from trona. Because evaporite minerals are soluble in most nonsaline liquids, using a water-based drilling fluid would quickly dissolve the trona core sample.

If a trona operator seeks to install an injection well for solution mining of trona, the methods employed would be mostly different than for an exploratory well. The program would initially use rotary drilling methods (i.e., the bit pulverizes the earth via the rotation of carbide buttons on the bit face). Rather than core recovery for examination, higher penetration rate and drilling efficiency are the goal. Upon nearing the targeted trona bed, rotary drilling may switch to core drilling, which allows for greater precision downhole (i.e., host formation and lithology) and more informed decision making. After drilling through the overburden layers, the targeted trona bed, and into the underlying strata, the borehole is cased with pipe, and the casing is cemented to the formation downhole. After the hole is sealed and the cement has cured, a smaller diameter bit is deployed down the hole to drill through the cement plug. Following this point, the operation is largely nondrilling related. The publicly available drilling is mapped in Figure 10-1 and shows completed drillholes that were used for defining the extents of the KSLA.

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Figure 10-1. Publicly Available Historical Drillholes.

As set out in Item 3.0 of this TR, the QP has relied on Section 9.2(2) of NI 43-101 to omit information required by NI 43-101F1 relating to sample, preparation, analyses and security, to which the QP and URC do not have access.

41

As a royalty holder, SWTRE do not have access to various forms of supporting technical, drilling, and assay data held by individual trona operators.

42

As a royalty holder, SWTRE do not have access to supporting technical mineral processing and metallurgical testing data for converting solution-mined brines and dry trona to soda ash products.

43

As a royalty holder, SWTRE do not have access to supporting technical information necessary to complete the data verification to estimate Mineral Resources.

44

This TR does not include an estimate of Mineral Reserves.

45

The Green River Basin has thick and laterally continuous trona beds that are suited for large-scale underground mining operations using a combination of room-and-pillar mining, longwall mining, and solution-mining techniques. Conventional underground mining methods dominate production within the Green River Basin, although solution mining has been increasingly adopted to recover additional trona resources and extend the life of the operations. The mines currently recover trona from beds 17, 20, 21, 24, and 25. A summary of the mining methods employed by each operator is provided in Table 16-1.

Table 16-1. Dry Mining Methods and Equipment

 CM = continuous miner

AFC = Armored Face Conveyor

FCT = Flexible Conveyor Train

Longwall mining is employed at the Westvaco Mine and the American Soda Operations. Longwall mining involves extracting large panels of trona using a mechanized shearer operating along a longwall face, ranging from 650 to 750 ft in width and up to nearly 10,000 ft in length. The shearer advances through the developed longwall panels by cutting a uniform slice (approximately 36–42 inches in depth) of trona as it travels back and forth along the face. Hydraulic roof supports advance with the shearer as the trona is removed, which allows the roof to collapse in a controlled manner behind the supports, as illustrated in Figure 16-1.

Trona mined by the longwall shearer is conveyed along the longwall face by an AFC installed beneath the hydraulic shields. The AFC serves as the primary conveying system for the mined material and a guide track that maintains the shearer’s alignment and stability during cutting operations. As the shearer advances along the longwall face, the cut trona is continuously loaded onto the AFC and transported toward the headgate, where the longwall panel intersects with a perpendicular mine entry (gate road).

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Figure 16-1. Conceptual Longwall Mining (A) Oblique View, (B) Close-Up of Shearer, (C) Profile View [Chambers and Boltz, 2023].

At the headgate, the trona is transferred to the conveyor belt through a stage loader. The stage loader feeds the material onto a conveyor belt located within the adjacent entry, positioned out by the headgate. The trona is then transported via a series of underground belt conveyors extending several miles through the existing underground mine workings to the shaft for hoisting to the surface for processing.

The Westvaco and American Soda underground mines operate multiple BM development sections responsible for constructing the underground network of main entries, gate roads, recovery, and setup rooms required to support longwall production panels. The BM extracts trona using a rotating cutting head assembly while roof support, in the form of roof bolts, is installed to stabilize the newly exposed ground.

The trona cut by the BM is loaded directly onto a shuttle car or FCT, which transports the material to the development section feeder breaker to transfer onto the mine-wide conveyor belt system for conveyance through the underground mine to the shaft skip loading station, where it is hoisted to the surface for processing.

The longwall method results in approximately 97 percent to 99 percent recovery in the panels, and recovery in the mains and gate roads varies from 25 percent to 50 percent for an overall areal recovery ranging from 55 percent to 70 percent, depending on the panel dimensions and geology of the trona bed.

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Room-and-pillar mining is the most widely used mining method in the Green River Basin and is employed by Şişecam and Tata. In this method, trona is extracted in a series of parallel entries, leaving pillars of trona in place to support the roof. The extraction ratio depends on the length of time the openings are required to be maintained and the subsidence profile. The mining layout typically consists of a grid of rooms separated by pillars to maintain ground stability. The openings (referred to as rooms) allow access for mining equipment, act as roadways, and provide utility distribution and ventilation airflow.

A typical room-and-pillar production section consists of a CM/BM, one or two roof bolting machines, two to three shuttle cars (or alternatively an FCT for haulage), and a feeder for the conveyor belt, as shown in Figure 16-2. The mining cycle begins when the CM/BM advances into the trona to create a cut (typically 14 to 30 ft wide). The mining height corresponds to the thickness of the trona bed (or the maximum height of the mining equipment) plus a small amount of underlying floor material that may be extracted during mining, which is referred to as out-of-seam dilution.

Figure 16-2. Typical Room-and-Pillar Mine [Arch Coal, Inc., 2010].

As the CM/BM cuts the trona, the broken material is loaded directly into a shuttle car or haulage unit. When filled, the shuttle car transports the material to a feeder breaker to meter the ROM trona onto the conveyor belt for transport out of the mine. The empty shuttle car then returns to the mining unit at the face while additional shuttle cars operate sequentially to maintain continuous production. This cycle continues until the trona within the cut has been completely extracted, after which the CM/BM withdraws and moves to the next mining location.

After the cut is complete, the exposed roof is stabilized with roof bolts. A roof bolting machine enters the mined area, drills holes into the roof strata, and installs roof bolts to provide ground support.

Room-and-pillar mining may be conducted using either advance or retreat methods. In advance mining, entries are developed, and pillars are left intact to support the roof; this approach is used by Şişecam. In retreat mining, when development advances to the limits of the planned mining area, mining proceeds in the reverse direction, and portions of the pillars are systematically recovered. Retreat mining includes partial pillar extraction and allows controlled roof collapse within the mined area, which can result in surface subsidence. Tata employs a partial pillar recovery retreat mining system as its production method in the panels. All operators leave the pillars in place in the development of the mains.

The room-and-pillar mining method has an approximate mining recovery of 35 percent to 65 percent in the mains and panels, respectively.

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Solution mining has become an increasingly important method for recovering trona resources in the Green River Basin for beds that cannot be economically extracted by conventional underground mining techniques. Solution mining of trona is separated into two types: passive (or secondary), and primary. The passive approach is used in operations such as the Granger facility operated by WE Soda and at Westvaco in areas that were previously mined using room-and-pillar methods.

In passive solution mining, wells are drilled into the trona deposit, and processing brines (or tailings solutions) are injected into previously mined underground voids. Over time, the injected brines dissolve the remaining trona pillars that were left behind during earlier mechanical mining operations. The resulting bearing brine is then pumped to the surface and processed through evaporation and crystallization facilities to produce soda ash. This method avoids the need for extensive underground mining infrastructure and enables recovery of trona from deposits that are thinner, deeper, or otherwise less suitable for conventional mining methods.

Primary solution mining involves drilling and developing caverns within the bedded trona layers. Heated brine is injected into the horizontal cavern to dissolve the trona minerals, which are then recovered to the surface where the trona-saturated brine is sent for processing. Over time, the cavern grows laterally and is then mined upward through the trona layers, as illustrated in Figure 16-3.

Underground trona mining operations use a range of specialized equipment designed to support continuous production in relatively soft evaporite deposits. Equipment commonly used in the Green River Basin includes longwall systems, CMs, BMs, shuttle cars, FCTs, roof bolting machines, and auxiliary ventilation fans of various makes and models. Operations such as Westvaco and American Soda operate a single longwall production panel supported by several development sections, whereas Şişecam and Tata primarily employ multiple BM or CM production sections to carry out their mining activities.

Personnel requirements vary depending on the mining method and production scale. Underground mining operations typically require hourly and salaried personnel, including operators, maintenance staff, engineering personnel, and administrative support. The Green River Basin trona mines are staffed with a workforce primarily from the surrounding southwestern Wyoming area. Table 16-2 provides end-of-year employment for the mines from 2021 to 2024 sourced from MSHA [2026]. Mine employment data for 2025 was sourced from the Wyoming State Mine Inspector’s Annual Report [State of Wyoming, 1949–2026]. Employment has been consistent from 2022 to 2024, with a slump in 2021 that was mostly caused by the COVID-19 pandemic.

49

Figure 16-3. Typical Solution-Mined Cavern Layout [Yu et al., 2023].

Table 16-2. Trona Operator Employee Count

Historical trona production for 2016 to 2025, as reported by the operators in the annual reporting to the State of Wyoming State Mine Inspector’s Office [State of Wyoming,1949–2026], converted to soda ash equivalent is shown in Figure 16-4. Production has been relatively consistent over the last 9 years and ranged between 10.2 and 12.3 Mt. The lower production amount is largely attributed to the 2020 COVID-19 pandemic.

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Figure 16-4. Trona Production From 2016 to 2025.

Based on the public disclosure of the operator companies, the following expansion projects are planned:

51

The operators convert trona ore, sodium sesquicarbonate dihydrate Na₂CO₃·NaHCO₃·2H₂O, into soda ash or anhydrous sodium carbonate (Na₂CO₃), and sodium bicarbonate (NaHCO₃) using standard unit processes common to the soda ash industry—the Sesquicarbonate (Sesqui) or Monohydrate (Mono) process. Solution mining of trona results in soda ash processed by Evaporation Lime Decahydrate Crystallization Monohydrate (ELDM) crystallization.

In the Sesqui process, the trona ROM material is dissolved first, which separates the insoluble materials, and then is filtered and dried. Converting bicarbonate takes place by calcining the purified crystals. Calcining drives off the water and carbon dioxide. Shown chemically, the simplified Sesqui process is shown as:

In the Mono process, the dry trona ROM material is calcined first and then dissolved for clarification followed by crystallization. The simplified Mono process is shown as:

The typical process flow steps are shown in Figure 17-1.

The WE Soda Mono and Sesqui plants at Westvaco convert dry-mined trona into soda ash. Crushing, dissolution in water, filtration, and crystallization techniques are used to produce the soda ash products. In the Mono process, shown in Figure 17-2, the ore is calcined with heat before dissolution, which converts the trona to soda ash by removing water and carbon dioxide. A final drying step using steam produces a dense soda ash product from the Mono process. In the Sesqui plant, the calcination is performed at the end of the process, producing light-density soda ash for end-use applications desiring increased absorptivity. The Sesqui process can also produce refined sodium sesquicarbonate.

Solution-mined trona is converted into dense soda ash at WE Soda’s ELDM operation at the Westvaco site and Granger facility. The steps to produce soda ash are similar to the dry-mined processes, except the crushing and dissolving steps take place when the trona is already in a water solution as it leaves the mine.

Secondary recovery of soda ash occurs from collecting and processing sodium carbonate decahydrate crystals that form in the tailings ponds. The decahydrate crystals are redissolved and processed through the monohydrate crystallizers.

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Figure 17-1. Typical Process Flow [Garrett, 1992].

Figure 17-2. WE Soda Monohydrate Process Flow [Reichl, 2023].

If the conversion of trona to soda ash is 100 percent efficient, the ratio of the trona to soda ash, 2Na₂CO₃ / 3Na₂CO₃, can be described by the molecular weight ratio of 2(226.03)/3(105.98) or 1.4218 tons of trona for every 1 ton of soda ash. The typical ratio conversion of trona to soda ash ranges from 1.5 to 1.8, which indicates an efficiency range of 79 percent to 92 percent.

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All plant facilities are accessible by spur rails, which connect to a nearby east-west main rail controlled by Union Pacific. A contract rail yard is available along La Barge Road (Highway 372) to allow for the assembly of unit trains.

Natural gas is used to produce process steam for soda ash production and at facilities with on-site power generation. During winter, natural gas is used by mines for heating the mine air intake. Figure 18-1 shows the available regional infrastructure.

With the exception of the American Soda plant, all operations have on-site power generation. American Soda’s power is purchased from Pacific Corp. (Rocky Mountain Power).

The operators use fresh surface water for power generation and solution mining. Water is provided by water rights accessed by pumping from the Green River, as described in Table 18-1. Water consumption is estimated based on the process to produce soda ash from mechanical mining, using 200 gallons per ton of soda ash, and the water requirement of the on-site power plant is 250 gallons per ton of soda ash.

The operating mines all have tailings management systems in place for surface and underground disposal, with the exception of Tata, which does not have tailings disposal underground.

To provide potable water to the mines, noncommunity public water systems are operated at the mine sites. Water withdrawn from the Green River is conveyed to the water treatment plant where it is treated and distributed throughout the facility.

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Figure 18-1. Regional Infrastructure.

Table 18-1. Water Rights by Operator [Purcell, 2000]