Support Activities for Nonmetallic Minerals (except Fuels) Mining

NAICS 213115 — An Investor's Primer

NAICS = North American Industry Classification System, the U.S. government's standard code for industries. Code 213115 covers the contractors that drill, blast, and develop nonmetallic-mineral mines for a fee — not the mines themselves.

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1. Overview

This is one of the smallest, most fragmented industries in all of U.S. mining, and one of the most commonly misunderstood. NAICS 213115 is not the companies that own quarries, sand pits, or industrial-mineral mines. It is the roster of contract-service firms that do specialized work for those operators on a fee or contract basis: drilling and blasting rock, stripping overburden, sinking shafts, dewatering, and running exploration core-drilling programs at mines producing crushed stone, sand and gravel, industrial (frac) sand, clay, gypsum, phosphate, potash, salt, and soda ash [1].

In federal-statistics terms it is tiny: the 2022 Economic Census counted 193 firms generating about $1.09 billion in revenue [2]. For scale, that is a rounding error against the roughly $112 billion of nonfuel minerals the U.S. mines each year [12] and against the ~$127 billion oil-and-gas field-services complex it sits beside [29].

Why an investor should still care: this niche is the labor-and-equipment layer beneath a vast physical-minerals economy that touches every road, building, farm, and shale well in the country. Understanding it clarifies how the aggregates, frac-sand, and fertilizer-mineral value chains actually make money.

The one thing to internalize up front: a 213115 firm is a service business with derived demand, not a commodity producer. It owns no reserves and is not a direct price-taker on any single commodity. Its revenue tracks its customers' volumes and capital budgets, which in turn track the underlying commodity cycles — construction for aggregates, oil-and-gas completions for frac sand, crop prices for fertilizer minerals. So commodity prices still drive it, but one step removed, through customer spending rather than through a ton sold.

Ways in. There is no pure-play, publicly traded 213115 company — the single most important investor takeaway. Public-market investors reach the theme indirectly, through the aggregate and mineral producers these contractors serve, the explosives and drilling majors, land/royalty companies, or infrastructure and materials exchange-traded funds (ETFs, baskets of stocks that trade like a single share). Private investors get closer: the contractors themselves are almost all privately owned, and per-ton mineral royalties are a distinct private asset class. Private equity (PE), not the public market, has been the marginal buyer across this whole cluster since 2024.

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2. What it is, and what it excludes

Formal scope. NAICS 213115 covers establishments primarily providing, on a fee or contract basis, support for the mining and quarrying of nonmetallic minerals except fuels — including traditional exploration (core sampling, test/prospect drilling, geological observation) [1]. Representative activities: contract drilling and blasting; test and production drilling; shaft sinking and tunneling; overburden removal (stripping) that is not general site preparation; and pumping/dewatering of mines [1].

What it deliberately leaves out — the codes a reader must not conflate:

Two consequences matter. First, a company casual observers call a "mining-services" firm may statistically sit under mine operation, manufacturing, engineering, construction, equipment rental, or transportation — not here. Second, EIA (U.S. Energy Information Administration) oil, gas, and coal production figures do not measure this industry's output — 213115 explicitly excludes fuels, so its physical-scale context comes from the USGS (U.S. Geological Survey), not the EIA [1].

Ownership mix. The industry is overwhelmingly private and closely held. The federal concentration data put the Herfindahl-Hirschman Index (HHI — the standard 0–10,000 market-concentration gauge; U.S. antitrust regulators treat anything below 1,500 as "unconcentrated") at just 295 — extraordinarily fragmented [2]. The four largest firms hold only 28.1% of revenue (the four-firm concentration ratio, CR4); the top 50 firms hold 82.4% [2]. County Business Patterns shows roughly 80% of establishments have fewer than 20 employees, and most are S-corporations, partnerships, or sole proprietorships — the classic signature of family- and founder-run regional businesses [3]. Public floats, foreign owners, and PE sponsors appear only one layer up (the producers) or one layer over (explosives and drilling majors).

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3. How big it is

The industry itself (213115). Revenue is collected only in Economic Census years, and the authoritative figure is $1,088.569 million (~$1.09 billion) for 2022 [2]. Alongside it, the 2022 Economic Census reported 193 firms, 202 establishments, 4,097 employees, $272.3 million of annual payroll, ~$905 million of value added, and ~$128 million of capital spending [2]. The more current County Business Patterns frame (2023) shows 207 establishments, 3,377 employees, $280.8 million of annual payroll, and $64.2 million of first-quarter payroll [3].

Honesty notes: the Census flagged that 20–30% of the industry's revenue and 10–20% of employment were imputed, so treat the totals as directional, not precise [2]. The employment gap between frames (4,097 vs. 3,377) is methodological (different surveys, reference weeks, coverage rules) plus seasonality — drilling, blasting, and stripping peak in warm-weather construction months, so a single mid-March reference week understates the full-year workforce [2][3]. Simple arithmetic on the Census totals implies roughly $5.6 million of revenue per firm, ~$266,000 per employee, and ~$66,500 of pay per employee (author's calculations, not Census-published ratios) [2]. The federal source set does not publish six-digit receipts for the long tail of one-person nonemployer contractors, so that sliver is uncounted here.

The Small Business Administration (SBA) size standard for the code is $20.5 million in average annual receipts; SBA estimated ~175 firms (about 90% of the industry) qualify as small [4].

The physical scale of the customer base (USGS, 2025). The mines 213115 serves are enormous in tonnage even though the support-services spend is modest. Physical production and reserves come from the USGS Mineral Commodity Summaries — a different, non-financial measure than the Census revenue above:

The three sand-and-stone categories alone produced about 2.49 billion metric tons in 2025 [5][6][7]. Set that against barely 200 establishments in 213115 and the apparent undercount becomes clear: most mine-support work is either self-performed by the producers themselves or classified under adjacent NAICS codes — a genuine boundary limitation of the statistics, not evidence the physical work is small.

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4. The investable universe

There is no clean, listed pure-play and no dedicated 213115 ETF. Exposure is built from four overlapping groups. Market caps move daily and are not part of the federal source data; sizes below are coarse tiers, and each name is a broader business than the 213115 activity.

A. Near-direct service exposure (as close as public markets get):

B. Producer equities (the main proxy — direct commodity/volume leverage):

• Aggregates: Vulcan Materials (NYSE: VMC) and Martin Marietta (NYSE: MLM), the two U.S. large-caps; plus CRH plc (NYSE: CRH), Eagle Materials (NYSE: EXP), Arcosa (NYSE: ACA), U.S. Lime & Minerals (Nasdaq: USLM).
• Frac sand: Atlas Energy Solutions (NYSE: AESI) — largest Permian proppant operator after buying Hi-Crush ($450M; ~28 million tons capacity) [28]; Smart Sand (Nasdaq: SND).
• Fertilizer minerals: Mosaic (NYSE: MOS), Intrepid Potash (NYSE: IPI).
• Salt / specialty: Compass Minerals (NYSE: CMP), Minerals Technologies (NYSE: MTX).

C. Land & royalty companies (own the ground, not the operation):

• FRP Holdings (Nasdaq: FRPH) — aggregate-bearing land leased to Vulcan, Martin Marietta, CEMEX; $12.9M of 2024 aggregate royalties [23].
• Natural Resource Partners (NYSE: NRP) — mineral interests, but with substantial coal exposure [24].
• Texas Pacific Land (NYSE: TPL) and LandBridge (NYSE: LB) — Permian sand, caliche, water, and surface-use revenue tied to oilfield activity, i.e., indirect energy-cycle exposure [25].

D. Private, PE, and foreign owners (where the actual contractors live): Boart Longyear (private, American Industrial Partners); Austin Powder (private, with a 2024 AIP investment); U.S. Silica (private, Apollo); Iron Oak Energy Solutions (Covia + Black Mountain, private); Turner Mining Group, Maine Drilling & Blasting, Aggregate Resource Industries, Maxam (private); and foreign-controlled U.S. producers CRH, Heidelberg/Amrize, CEMEX, Carmeuse, Lhoist [18][19][28].

The leverage. Aggregate names are the steadier, higher-quality exposure (infrastructure-backed local pricing); frac-sand names behave like high-beta oil-services stocks; fertilizer-mineral names are global price-takers. All carry the classic boom-bust capital-return pattern — payouts swell near cycle peaks and get cut when prices fall.

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5. How the money works

Because 213115 is a service business, its economics differ in kind from the producers it serves. A reader needs both models.

The contractor's model. Simplified: billable volume or time × contract rate, minus labor, fuel, explosives and consumables, fleet maintenance and mobilization, depreciation, insurance, and compliance [Codex synthesis]. Firms bill by the foot drilled, by the hole or ton blasted, by the cubic yard of overburden moved, by the meter cored, or on day-rate/turnkey and cost-plus contracts. The contractor owns no reserves, and has no lifting cost, finding-and-development cost, or all-in sustaining cost of its own — those belong to the customer. Its real assets are trained and licensed crews, a safety record, fleet reliability, permits and explosives-handling capability, and proximity (mobilizing rigs is expensive, so nearby work wins). The Census profile — ~83% value added and ~25% payroll as a share of receipts, with capital spending near 12% of revenue — confirms a people-and-iron business, moderately capital-intensive, where equipment utilization is the master margin lever: idle rigs still carry depreciation, financing, and core labor [2].

How the commodity cycle reaches it. Commodity (or local aggregate) prices move the mine owner's margin → the owner adjusts production, stripping, development, and exploration budgets → outsourced contractor volumes and rig utilization move → and fixed fleet costs magnify the swing at the contractor level. Discretionary work — exploration, project development — is cut first; recurring production drilling and blasting is stickier. The live example: in 2024 a frac-sand oversupply pushed prices down and idled mines (U.S. Silica's oil-and-gas proppant revenue fell 38% in the first half of 2024 on ~23% lower price and ~19% lower volume), and the contractors serving those mines saw work evaporate — commodity cyclicality inherited without owning a ton [7][28].

The customers' model — three flavors of commodity economics:

• Aggregates (stone, construction sand) — a local, freight-limited business. These are low-value, high-weight materials; hauling can cost as much as the rock, so competition and pricing are regional, not national or global. The moat is a permitted, specification-grade reserve near a growing market, not geological scarcity. Vulcan's 2025 figures illustrate it: 226.8 million tons shipped at a $21.98 freight-adjusted price per ton, $8.66 gross profit per ton, against 16.6 billion tons of reserves — roughly 73 years at current output; Martin Marietta's ~16.9 billion tons imply ~87 years (simple static math, not company forecasts) [21][22].
• Globally traded minerals (phosphate, potash, soda ash) — pure price-takers. Exposed to world supply, imports, exchange rates, and freight; U.S. potash is 92% net-import reliant, and more than half of U.S. soda ash is exported [9][10].
• Frac sand — regional but violently cyclical, prone to basin-level oversupply [7].

For comparison, the KPIs generalists know from oil and gas (lifting cost, finding-and-development (F&D) cost, netback — the per-barrel margin after costs) and from metals (all-in sustaining cost (AISC), ore grade) are not the natural yardsticks here, because fuels are excluded and aggregates/industrial minerals are not reported that way. The useful measures are cash cost per ton, freight-adjusted price per ton, stripping ratio, product grade/purity, permitted reserve life, and plant/fleet utilization [21].

Royalties and mineral rights — the mirror image. Owning the land and mineral rights under a quarry earns a per-ton or percentage-of-sales royalty with no operating cost or sustaining capital — genuine commodity and volume exposure, opposite in profile to the fee-earning contractor. The royalty owner still bears depletion, operator credit, permitting, and title risk [23][24]. Do not blur the two: the contractor earns a service fee regardless of the commodity price (until volumes fall); the royalty owner earns a slice of production value regardless of the operator's costs.

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6. What drives demand

Demand is entirely derived from the end-markets of the minerals the customers mine:

1. Construction & infrastructure — the dominant, steadiest leg. About 72% of crushed stone and the bulk of construction sand feed roads, bridges, concrete, and buildings [5][6]. Highway, water/sewer, transit, manufacturing-plant, data-center, and energy construction — underpinned by the 2021 Infrastructure Investment and Jobs Act (IIJA) — set multi-year quarry volumes and therefore drill-and-blast work.
2. Oil & gas completions — the most volatile leg. ~81% of industrial sand is frac/well-service sand; demand tracks completed wells, lateral length, and sand intensity per foot, which track rig activity and the oil price (WTI = West Texas Intermediate, the U.S. benchmark crude) [7]. The onshore rig count slipped from an average 582 in 2024 to 549 over the first ten months of 2025 [7].
3. Agriculture — secular and defensive. Over 95% of phosphate rock and ~85% of potash go to fertilizer; demand follows crop prices, acreage, and farm income, with no agronomic substitute for phosphorus or potassium [8][9].
4. Glass, chemicals, and de-icing. Soda ash (glass, chemicals) and salt (chemical feedstock plus weather-driven highway de-icing) add diversified, partly weather-sensitive baseline demand [10][11].
5. Critical minerals & electrification — an emerging, long-dated option. The final 2025 U.S. critical-minerals list added phosphate and potash, and domestic-supply policy could fund new exploration and mine-development drilling — the higher-margin end of 213115 — though exploration success is slow to convert into permitted, financed mines [8][9].

Net: a stable construction/agriculture core with a volatile frac-sand overlay.

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7. Regulation

Land tenure — three federal systems, but private/state land dominates. The General Mining Law of 1872 does not apply uniformly here. Certain nonmetallic minerals (fluorspar, some gypsum/limestone, gemstones) are locatable under that law; since 1955 common sand, gravel, and stone are saleable materials that the Bureau of Land Management (BLM) disposes of via sales contracts or free-use permits; and potash, sodium, and phosphate are leasable, carrying federal rent and royalties [27]. In practice, most U.S. aggregate and industrial-mineral operations sit on private or state land, so the binding constraints are usually state permitting, local zoning, and safety rules, with BLM leasing relevant only to the federal-land subset [27].

MSHA (Mine Safety and Health Administration). Federal safety jurisdiction reaches contractors working on mine sites, not just operators. Surface stone/sand/gravel work falls under Part 46 training: new miners generally need 24 hours of training within 90 days (at least 4 before starting work) plus 8 hours of annual refresher [13]. A contractor's MSHA citation and injury history directly affects its ability to bid for major customers, its insurance cost, and its labor retention [13].

Respirable silica — watch the current status. MSHA's 2024 rule set a stricter 50-microgram-per-cubic-meter exposure limit (25-microgram action level), but a court challenge led MSHA on April 6, 2026 to indefinitely delay the metal/nonmetal compliance deadlines pending judicial review; the older Part 56/57 standards remain in force. Do not model the delayed date as operative, but treat tighter silica controls as an eventual, material equipment-and-monitoring cost [14].

Environmental permitting. Mine wastewater discharges need Clean Water Act (CWA) NPDES (National Pollutant Discharge Elimination System) authorization, mostly administered by state programs; crushing and screening equipment can fall under Clean Air Act (CAA) dust standards (40 CFR Part 60, Subpart OOO) [26]. Add state mine-reclamation and blasting-vibration permits (setbacks, seismograph monitoring, pre-blast surveys), state severance/property taxes on the producer, and — critically for aggregates — local zoning and haul-route/noise/vibration rules that can stop an otherwise valuable reserve from ever being mined.

Explosives & ESG. Contract blasting is additionally licensed by the ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives), DOT (Department of Transportation), and state fire marshals — a real barrier favoring established operators. Dust, noise, vibration, water use, and diesel emissions draw community scrutiny. But because the end-markets are construction and agriculture, 213115 carries far less energy-transition/stranded-asset risk than coal or oil support — the frac-sand slice is the main transition-exposed segment.

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8. Competitive dynamics and consolidation

Within 213115: fragmented, local, and stable — the HHI of 295 quantifies it [2]. Fragmentation persists because individual quarry contracts are small, mobilization cost favors nearby fleets, geology and blasting conditions are site-specific, and customers value an incumbent's safety and performance record [3]. Barriers rise for underground/specialty drilling, large production-blasting, explosives handling, and bonded national accounts, but no national roll-up of the contractors has occurred. The ceiling on pricing is the customer's make-or-buy choice: any producer can compare outsourcing against buying rigs and hiring its own crews.

One layer up, the customers are consolidating hard. Recent deals: Apollo took U.S. Silica private (July 2024); American Industrial Partners took Boart Longyear private (April 2024) and invested in Austin Powder (July 2024); and Quikrete acquired Summit Materials for ~$11.5 billion of enterprise value (completed February 2025) [18][19][20]. Even so, ownership upstream stays fragmented — Martin Marietta estimates 67% of U.S. aggregates production is privately held and 33% public, and the top ten producers account for only ~35% of output [22]. A consolidating, more sophisticated customer base tends to insource more work and tighten contract terms — a structural headwind for small independent contractors — while PE, not the public market, is currently setting the price for assets adjacent to this activity [18][19][20].

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9. Risks

1. Commodity-price/volume cyclicality — the central risk. Producer and royalty earnings move directly with price and volume; the contractor's exposure arrives later, through customer budgets and fleet utilization, and discretionary exploration/development is cut first. The 2024 frac-sand idling is the live case [7][28].
2. Local construction downturns. Public works cushion aggregate demand, but residential and private nonresidential building remain cyclical, and weather shifts shipments between quarters [5][6].
3. Cost inflation without pass-through. Diesel, steel, ammonium-nitrate-linked explosives, tires, insurance, and skilled-labor wages can outrun locally-bid service prices; fixed-price contracts without escalators can turn loss-making.
4. Customer concentration & insourcing. A small contractor may depend on one mine or a few quarries; closure, rebidding, ownership change, or insourcing can wipe out a book overnight — a risk NACCO's disclosed 25%/10% customer concentration shows persists even at scale [15].
5. Permitting and regulatory delay. Zoning, environmental, blasting-vibration, and reclamation approvals can take years, and for aggregates delay is magnified because pushing a reserve farther from demand raises freight cost [6].
6. Depletion and stranded location. The contractor's local revenue base disappears when a customer mine exhausts or closes; a frac-sand deposit can strand when drilling shifts basins even though the sand remains [7][8].
7. Capital intensity and idle iron. Specialized fleets earn poorly when idle; debt-financed expansion at the top of the cycle is especially dangerous as residual equipment values fall with utilization.
8. Safety and environmental tail events. Fatalities, silica disease, misfires, flyrock, vibration damage, and water violations can trigger shutdowns, litigation, and loss of customer qualification [13].
9. Global oversupply and imports for the traded minerals (potash, phosphate, soda ash) [9][10].
10. Energy-transition risk — comparatively low, concentrated in the frac-sand and Permian-royalty segments rather than the construction/agriculture core.
11. Data/classification risk. With ~200 establishments and heavy Census imputation, small reclassifications can swing measured totals, and comparable companies report broader segments — so market-share estimates are unreliable [2][3].

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10. How to invest, and outlook

Public routes. No pure-play exists, so build the exposure deliberately:

• Producer equities carry the direct commodity/volume leverage — steadier, infrastructure-backed aggregate names (VMC, MLM) versus high-beta frac-sand names (AESI) versus globally price-taking fertilizer minerals (MOS, IPI).
• Explosives/drilling majors (Orica; Major Drilling) are the closest listed proxies for the service activity itself, though both are diversified and Major Drilling leans to metals [16][17].
• Royalty & land companies (FRPH for focused aggregate royalties; NRP with coal mixed in; TPL/LB for Permian sand-and-water) offer high-margin, operator-funded exposure — but a royalty is not a bond: volume, price formulas, depletion, and operator credit all vary [23][24][25].
• ETFs give only diffuse exposure: SPDR S&P Metals & Mining (XME) is metals/steel-heavy, and Global X U.S. Infrastructure Development (PAVE) is an infrastructure-spending basket that captures aggregate demand indirectly, not mining services [30]. Broad materials funds (XLB, VAW) hold the producers in diluted form.
• Mind the payout pattern: commodity producers distribute more cash near cycle peaks, then cut or preserve liquidity when prices fall — do not capitalize peak special dividends or buybacks as a perpetual yield.

Private routes. This is where genuine 213115 exposure is actually ownable:

• Direct/PE ownership of the contractors — regional drill-and-blast, stripping, dewatering, and exploration-drilling firms bought for cash flow, safety record, and customer contracts, then rolled up for fleet density and utilization. The 2024–25 take-privates confirm PE appetite [18][19]. The strongest profile combines recurring production (not just exploration) work, several nearby customers, inflation pass-through, a clean MSHA record, a moderate-age fleet, and low key-person dependence.
• Mineral & royalty interests — a per-ton royalty on a permitted quarry near a growing metro area offers low operating capital and inflation-linked pricing, offset by depletion and operator/permitting concentration.
• Note the boundary: operating the mine moves the investment into NAICS 2123, and owning the mineral rights is a different risk/return profile again.

Outlook (forward-looking judgment, not a sourced forecast). The construction/aggregate and agriculture/fertilizer legs — most of the addressable work — sit on a stable multi-year floor from infrastructure spending, housing need, and food demand; local permitting scarcity even supports aggregate pricing [5][6]. The frac-sand overlay remains the swing factor, following completions and prone to the oversupply seen in 2024 [7]. The 2017→2022 revenue jump (+37% to ~$1.09 billion) was flattered by that window's shale-and-aggregate boom; a normalized path looks like low-to-mid single-digit annual growth, tracking construction volumes and mine capital spending [2]. Consolidation pressure — from PE-owned, insourcing customers — will keep favoring scaled, safety-leading, technology-enabled contractors, while critical-minerals and reshoring policy adds real but long-dated upside to the exploration/development side.

Bottom line: NAICS 213115 is a small, fragmented, privately owned contract-services layer beneath a very large physical-minerals economy — cyclical through its customers rather than as a direct price-taker, low on transition risk, with no public pure-play. Generalists who want the theme should own the producers, royalty owners, and explosives/drilling majors; those who want the activity itself must do it privately.

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Sources

1. U.S. Census Bureau. North American Industry Classification System (NAICS) — 213115 definition and 2022 Manual. 2022. https://www.census.gov/naics/?input=213115&year=2022
2. U.S. Census Bureau. 2022 Economic Census, Mining Sector — NAICS 213115 national totals and concentration (receipts, firms, employees, payroll, value added, CR4/CR8/CR20/CR50, HHI). 2024. https://www.census.gov/data/tables/2022/econ/economic-census/naics-sector-21.html
3. U.S. Census Bureau. County Business Patterns (2023), NAICS 213115 — establishments, employment, payroll, legal form and size distribution. 2024. https://www.census.gov/programs-surveys/cbp.html
4. U.S. Small Business Administration. Table of Small Business Size Standards (13 CFR 121.201) — NAICS 213115 = $20.5 million; 2025 size-standard analysis. 2023–2025. https://www.sba.gov/document/support-table-size-standards
5. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Stone (Crushed). 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-stone-crushed.pdf
6. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Sand and Gravel (Construction). 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-sand-gravel.pdf
7. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Sand and Gravel (Industrial). 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-sand-industrial.pdf
8. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Phosphate Rock. 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-phosphate.pdf
9. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Potash. 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-potash.pdf
10. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Soda Ash. 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-soda-ash.pdf
11. U.S. Geological Survey. Mineral Commodity Summaries 2026 — Salt. 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-salt.pdf
12. U.S. Geological Survey. National news release: value of U.S. nonfuel mineral production (~$112 billion, 2025). 2026. https://www.usgs.gov/news/national-news-release/value-us-mineral-production-rose-last-year-driven-precious-metals-prices
13. U.S. Department of Labor, Mine Safety and Health Administration (MSHA). Mine Safety and Health at a Glance; Part 46 training for independent contractors. 2026. https://www.msha.gov/mine-safety-and-health-glance-fiscal-year
14. MSHA / Federal Register. Lowering Miners' Exposure to Respirable Crystalline Silica (2024 rule) and April 6, 2026 delay of metal/nonmetal conforming amendments. 2024–2026. https://public-inspection.federalregister.gov/2026-06584.pdf
15. NACCO Industries. Form 10-K for year ended December 31, 2025 (Contract Mining segment). 2026. https://www.sec.gov/Archives/edgar/data/789933/000078993326000070/nacco-20251231.htm
16. Orica Limited. FY2025 Investor Presentation; Dyno Nobel Limited, Annual Report 2025. 2025. https://www.orica.com/ArticleDocuments/303/FY25%20Investor%20Presentation%20Final.pdf.aspx
17. Major Drilling Group International. Annual Report 2025. 2025. https://www.majordrilling.com/project-type/annual-report/
18. American Industrial Partners. Take-private of Boart Longyear (April 2024); strategic investment in Austin Powder (July 2024). 2024. https://americanindustrial.com/american-industrial-partners-completes-take-private-acquisition-of-boart-longyear/
19. Apollo Global Management / U.S. Silica. U.S. Silica completes transaction with Apollo Funds. July 2024. https://www.prnewswire.com/news-releases/us-silica-completes-transaction-with-apollo-funds-302211472.html
20. Summit Materials / Quikrete. Summit Materials completes merger with Quikrete (~$11.5B EV). February 2025. https://www.prnewswire.com/news-releases/summit-materials-completes-merger-with-quikrete-302372579.html
21. Vulcan Materials. Form 10-K for year ended December 31, 2025 (shipments, price/ton, reserves). 2026. https://www.sec.gov/Archives/edgar/data/1396009/000162828026009546/vmc-20251231.htm
22. Martin Marietta Materials. 2025 Capital Markets Day and Form 10-K (reserves; ownership split; top-10 share). 2025–2026. https://www.sec.gov/Archives/edgar/data/916076/000119312526059193/mlm-20251231.htm
23. FRP Holdings. 2025 Investor Day Presentation (2024 aggregate royalties). 2025. https://www.sec.gov/Archives/edgar/data/844059/000084405925000027/frphinvestorday25.htm
24. Natural Resource Partners L.P. Form 10-K for year ended December 31, 2025. 2026. https://www.sec.gov/Archives/edgar/data/1171486/000143774926006147/nrp20251231_10k.htm
25. Texas Pacific Land Corp. and LandBridge Company. Forms 10-K for year ended December 31, 2025. 2026. https://www.sec.gov/Archives/edgar/data/1811074/000181107426000018/tpl-20251231.htm
26. U.S. Environmental Protection Agency. Industrial Wastewater — Mining (CWA/NPDES); New Source Performance Standards, Nonmetallic Mineral Processing (CAA, 40 CFR Part 60 Subpart OOO). 2026. https://www.epa.gov/npdes/industrial-wastewater
27. U.S. Bureau of Land Management. About Mining and Minerals; Non-Energy Leasable Materials (locatable / saleable / leasable tenure). 2026. https://www.blm.gov/programs/energy-and-minerals/mining-and-minerals/about
28. Frac-sand consolidation reporting, 2024: Atlas Energy Solutions / Hi-Crush ($450M; ~28 Mt); Covia + Black Mountain → Iron Oak; U.S. Silica proppant pricing (Form 10-Q, Q2 2024). 2024. https://www.sec.gov/Archives/edgar/data/1524741/000152474124000018/slca-20240630.htm
29. IBISWorld. Oil & Gas Field Services in the U.S. — sector-scale context (~$127 billion). 2026. https://www.ibisworld.com/classifications/naics/213115/support-activities-for-nonmetallic-minerals-except-fuels-mining/
30. State Street Global Advisors, SPDR S&P Metals & Mining ETF (XME); Global X, U.S. Infrastructure Development ETF (PAVE). 2026. https://www.ssga.com/us/en/individual/etfs/state-street-spdr-sp-metals-mining-etf-xme