ALLIANCE RESOURCE PARTNERS LP 10-K

ITEM 2. PROPERTIES ​ COAL MINERAL RESOURCES AND RESERVES ​ Overview of Coal Properties ​ Our coal properties are located in the Illinois Basin and the Appalachia Basin. Our Illinois Basin properties are located in western Kentucky, southern Illinois, and southern Indiana. Our Appalachian properties are located in eastern Kentucky, Maryland, western Pennsylvania, and northern West Virginia. Mining operations on our coal properties consist of underground mines that produce bituminous coal that is sold to customers principally for electric power generation (thermal) and the production of steel (metallurgical). In addition to our coal mining operations, we also hold coal mineral interests that we lease/sublease to our operations or hold for lease/sublease to our operations or others. For a detailed overview of our coal mining operations and our coal royalty activities, please see "Item 1. Business—Coal Mining Operations" and "Item 1. Business—Mineral Interest Activities", respectively. ​ Evaluation and Review of Coal Mineral Resources and Reserves ​ Numerous uncertainties are inherent in estimating coal mineral resources and reserves, and the estimates are subject to change as additional information becomes available or circumstances change. Significant factors and assumptions related to the uncertainty in estimating coal mineral reserves and resources include: ​ ● geological and mining conditions, which may not be fully identified by available exploration data and/or differ from our experiences in areas where we currently mine; ● the percentage of coal in the ground ultimately recoverable; ● historical production from the area compared with production from other producing areas; ● the assumed effects of regulation and taxes by governmental agencies; ● future improvements in mining technology; and ● assumptions concerning future coal prices, operating costs, capital expenditures, severance and excise taxes, and development and reclamation costs. ​ Each of the factors which impacts reserve and resource estimation may vary considerably from the assumptions used in making the estimation and, as a result, the estimates in this report may not accurately reflect the actual coal reserves and resources. Actual production, revenues and expenditures with respect to the coal reserves will likely vary from the assumptions used in these estimates, and these variances may be material. Government regulations and other pressures may result in the closure of coal-fired electric generating plants earlier than assumed. Such changes would reduce the economic viability of our mining operations and could have a material adverse impact on our operations and financial results. ​ Under SEC rules, a mineral resource is a concentration or occurrence of 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 economic extraction. A mineral resource is a reasonable estimate of mineralization, taking into account relevant factors such as cut-off grade, likely mining dimensions, location or continuity that, with the assumed and justifiable technical and economic conditions, is likely to, in whole or in part, become economically extractable. A mineral reserve is an estimate of tonnage and grade or quality of indicated and measured mineral resources that, in the opinion of the qualified person, can be the basis of an economically viable project. More specifically, it is the economically mineable part of a measured or indicated mineral resource, which includes diluting materials and allowances for losses that may occur when the material is mined or extracted. ​ The coal mineral resource and reserve estimates included in this Annual Report on Form 10-K were prepared by an independent, qualified engineering firm, RESPEC. We provided RESPEC with property control, mine plans, production, revenue, costs, capital, and other information considered by RESPEC in making their estimates. As part of our internal controls, our geologists and engineers review the integrity, accuracy, and timeliness of the data provided to RESPEC that they considered in calculating their coal mineral resource and reserve estimates. We also review the geologic data, mining assumptions, and methodology used by RESPEC to estimate our coal mineral resources and reserves. Our geologists and engineers also met with RESPEC periodically during the year to discuss the assumptions and methods used in the coal mineral resource and reserve estimation process. 60 Table of Contents ​ RESPEC, an independent third-party engineering firm, does not own an interest in any of our properties and is not employed on a contingent basis. RESPEC prepared the initial TRS for each of our material mining properties. The TRSs will be updated when there are material changes to the coal mineral reserve or resource estimates. The most recent TRSs for our material mining operations are included as exhibits to our Annual Report on Form 10-K. ​ Summary of Coal Mineral Resources and Reserves ​ Coal Mineral Resources ​ Most of our coal properties designated as mineral resources are of thickness, quality, and mineability similar to that of the mineral reserves, and all are proximal to existing infrastructure such as power, water, transportation, facilities, etc. However, we have not completed pre-feasibility or feasibility studies with respect to our coal properties designated as mineral resources, as is required to convert the mineral resources into mineral reserves. There is no certainty that all or any part of the mineral resources will be converted into mineral reserves. ​ The following table sets forth our coal mineral resources, exclusive of coal mineral reserves, at December 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Heat ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Content (Btus ​ Pounds SO2 per MMBtu ​ Resource Classification ​ Ownership ​ ​ ​ Resources (tons in millions) per pound) <1.2 1.2-2.5 >2.5 Measured Indicated Combined Inferred Owned Leased Total ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ Illinois Basin ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dotiki (KY) 12,100 — 2.3 73.7 51.2 24.8 76.0 — 27.6 48.4 76.0 ​ Henderson/Union (KY) 11,450 — 3.0 409.7 127.3 227.9 355.2 57.5 74.0 338.7 412.7 ​ River View (KY) 11,450 ​ — ​ — ​ 0.3 ​ — ​ — ​ — ​ 0.3 ​ — ​ 0.3 ​ 0.3 ​ Sebree South (KY) 11,750 — — 43.5 22.1 16.8 38.9 4.6 0.3 43.2 43.5 ​ Hamilton County (IL) 11,650 5.1 33.8 405.8 191.2 242.3 433.5 11.2 32.8 411.9 444.7 ​ Region Total ​ ​ 5.1 ​ 39.1 ​ 933.0 ​ 391.8 ​ 511.8 ​ 903.6 ​ 73.6 ​ 134.7 ​ 842.5 ​ 977.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Appalachian Basin ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mountain View (WV) 13,200 — 0.4 8.3 4.1 4.4 8.5 0.2 1.8 6.9 8.7 ​ Tunnel Ridge (WV) ​ 12,600 ​ — — 0.9 — 0.2 0.2 0.7 0.7 0.2 0.9 ​ Penn Ridge (PA) 12,500 — — 78.0 21.9 53.2 75.1 2.9 78.0 — 78.0 ​ Region Total ​ ​ — ​ 0.4 ​ 87.2 ​ 26.0 ​ 57.8 ​ 83.8 ​ 3.8 ​ 80.5 ​ 7.1 ​ 87.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ ​ 5.1 ​ 39.5 ​ 1,020.2 ​ 417.8 ​ 569.6 ​ 987.4 ​ 77.4 ​ 215.2 ​ 849.6 ​ 1,064.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ % of Total ​ ​ ​ 0.5% ​ 3.7% ​ 95.8% ​ 39.2% ​ 53.5% ​ 92.7% ​ 7.3% ​ 20.2% ​ 79.8% ​ 100.0% ​ (1) Combined resources are defined as measured plus indicated resources. ​ At December 31, 2023, we had approximately 1.065 billion tons of coal mineral resources. Tonnages are reported on a clean recoverable basis with average long-term pricing based on available third-party forecasts and historical pricing adjusted for quality at the end of 2023 in a range from approximately $53 to $59 per short ton in the Illinois Basin and from approximately $62 to $119 per short ton in the Appalachian Basin, which are the prices used by RESPEC to estimate the amount of coal mineral resources. Coal sales prices vary based on coal quality, access to transportation, and other factors at each location. All resources are classified as underground mineable in the exploration stage. ​ Coal Mineral Reserves ​ Reserves are assigned to our active operations and are (1) currently in production, (2) economically viable, and (3) meet the other requirements to be considered reserves as defined by the SEC. ​ 61 Table of Contents The following table sets forth coal mineral reserve information, exclusive of the coal mineral resources above, at December 31, 2023, about our coal operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Heat ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Content (Btus ​ Pounds SO2 per MMBtu ​ Classification ​ Ownership ​ ​ ​ Reserves (tons in millions) per pound) <1.2 1.2-2.5 >2.5 Proven Probable Owned Leased Total ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Illinois Basin Operations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Warrior (KY) 12,300 — — 50.0 39.5 10.5 13.0 37.0 50.0 ​ River View (KY) 11,450 — — 310.4 169.1 141.3 58.0 ​ 252.4 310.4 ​ Hamilton County (IL) 11,650 — — 119.8 54.5 65.3 20.3 ​ 99.5 119.8 ​ Gibson South (IN) 11,500 0.9 9.5 34.8 35.6 9.6 15.3 29.9 45.2 ​ Region Total ​ ​ 0.9 ​ 9.5 ​ 515.0 ​ 298.7 ​ 226.7 ​ 106.6 ​ 418.8 ​ 525.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Appalachian Basin Operations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ MC Mining (KY) 12,800 9.6 0.5 — 7.8 2.3 — 10.1 10.1 ​ Mountain View (WV) 13,200 — 4.4 5.1 9.1 0.4 — 9.5 9.5 ​ Tunnel Ridge (WV) 12,600 — — 118.2 64.5 53.7 11.7 106.5 118.2 ​ Region Total ​ ​ 9.6 ​ 4.9 ​ 123.3 ​ 81.4 ​ 56.4 ​ 11.7 ​ 126.1 ​ 137.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ ​ 10.5 ​ 14.4 ​ 638.3 ​ 380.1 ​ 283.1 ​ 118.3 ​ 544.9 ​ 663.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ % of Total ​ ​ ​ 1.6% ​ 2.2% ​ 96.2% ​ 57.3% ​ 42.7% ​ 17.8% ​ 82.2% ​ 100.0% ​ ​ On December 31, 2023, we had approximately 663.2 million tons of coal mineral reserves. Tonnages are reported on a clean recoverable basis with average long-term pricing based on available third-party forecasts and historical pricing adjusted for quality at the end of 2023 in a range from approximately $53 to $59 per short ton in the Illinois Basin and from approximately $62 to $119 per short ton in the Appalachian Basin, which are the prices used by RESPEC to estimate the amount of coal mineral reserves. Coal sales prices vary based on coal quality, access to transportation, and other factors at each location. All reserves are classified as underground mineable in the development or production stage. ​ Mining Operations ​ The following table sets forth production and other data about our mining operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tons Produced ​ ​ ​ ​ Operations Location 2023 2022 2021 Transportation Equipment ​ ​ ​ (in millions) ​ ​ ​ ​ ​ Illinois Basin Operations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Warrior Kentucky 4.4 4.1 4.1 CSX, NS, PAL, truck, barge CM ​ River View Kentucky 9.9 10.2 9.9 Truck, barge CM ​ Hamilton County Illinois 5.6 4.7 4.9 CSX, EVW, NS, barge LW, CM ​ Gibson South Indiana 5.3 5.3 3.3 CSX, NS, truck, barge CM ​ Region Total ​ ​ 25.2 24.3 22.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Appalachian Basin Operations ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ MC Mining/Excel Kentucky 1.2 1.5 1.3 CSX, truck, barge CM ​ Mountain View West Virginia 0.8 1.4 1.5 CSX, truck LW, CM ​ Tunnel Ridge West Virginia 7.7 8.3 7.2 CSX, NS, barge LW, CM ​ Region Total ​ ​ 9.7 11.2 10.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ TOTAL ​ ​ 34.9 35.5 32.2 ​ ​ ​ ​ ​ CSX - CSX Railroad EVW - Evansville Western Railroad NS - Norfolk Southern Railroad PAL - Paducah & Louisville Railroad CM - Continuous Miner LW - Longwall 62 Table of Contents ​ Individual Property Disclosures ​ We consider the following properties to be material based on multiple factors including, but not limited to, the property's contribution to our overall business and financial condition. Please see Coal Mineral Resources and Coal Mineral Reserves above for information about the coal mineral resources and reserves held by these material properties. In addition to the following information, TRSs for these material properties with additional information are included as exhibits to this Annual Report on Form 10-K. ​ Henderson/Union Resources ​ The Henderson/Union Resources are located in Henderson and Union counties, Kentucky at 37°44'30"N, -87°46'07"W and we currently have control in over 1,600 tracts encompassing over 127,000 acres. The property is controlled through both fee ownership and leases of the coal. The coal mineral resources are controlled by Alliance Resource Properties. The base leases are with private owners and WKY CoalPlay or its subsidiaries, which are related parties. See "Item 8. Financial Statements and Supplementary Data — Note 20 – Related-Party Transactions" for more information about our WKY CoalPlay transactions. These base leases generally provide for a term that can be extended until exhaustion of the leased coal. Local infrastructure is as follows: ​ Major Roads: Interstates 69 and US-60, Railroads: None, Airport: Evansville Regional Airport (EVV), Town: Morganfield, Docks: River View, Hamilton 1, UC Processing, on the Ohio River, Water: Local municipalities and mine sources, Electricity: Kentucky Utilities (KU), Personnel: Regional. ​ 63 Table of Contents ​ Description ​ The potential underground mine(s) would utilize room-and-pillar methods operating a heavy media, float/sink style preparation plant. Exploration continues as needed to fulfill possible permitting and development requirements. Multiple access points are available for development. Access is available from the active River View complex, which began production in 2009. All equipment, facilities, infrastructure, and underground development are in good working order and maintained to industry standards. Access at the Hamilton and UC Coal, LLC sites are considered "brownfield" developments. Though some facilities and permitting are in place, significant upgrades to existing infrastructure and new construction would be needed to bring them into good working order that meets industry standards. The property associated with Henderson/Union has no book value as of December 31, 2023 but does have outstanding advanced royalties with WKY CoalPlay or its subsidiaries. See "Item 8. Financial Statements and Supplementary Data — Note 20 – Related-Party Transactions" for more information about advanced royalties that Henderson/Union has with WKY CoalPlay. ​ Though there is geographic overlap between the Henderson/Union and River View properties, the resources and reserves of each are associated with different coal seams or, if in the same seam, are separated by existing mine works or geologic features into distinct areas. There is no overlap in the resource / reserve estimation. ​ History ​ The Henderson/Union property contains resources in three coal seams, the WKY11, the WKY7, and the WKY6. Island Creek operated mines in the area and controlled a portion of the property. Under a joint venture, Texas Gas Service also controlled a large interest in the mineral rights. Lastly, Peabody and Patriot operated mines in the area and controlled a portion of the reserves. We consolidated control of the property through multiple transactions from 2005 through 2015. Island Creek operated the Ohio #11 mine. Peabody and later Patriot operated the Camp complex and Highland #11 mine to the southeast and east. The WKY11 seam was mined at these locations. No mining has occurred on the property in the 64 Table of Contents WKY7 or WKY6 seams. In general, all drilling has shown highly consistent coal seams of mineable thickness and quality for the high-sulfur thermal utility market. ​ Encumbrances ​ Our credit facility is secured by, among other things, liens against certain Henderson/Union surface properties and coal leases. Documentation of such liens is of record in the Offices of the Henderson and Union County Clerks. Please read "Item 8. Financial Statements and Supplementary Data — Note 6 – Long-term Debt" for more information on our credit facility. ​ The KYDNR, DMP is responsible for the review and issuance of all permits relative to coal mining and reclamation activities, and financial assurance of comprehensive environmental protection performance standards related to surface and underground coal mining operations. In addition to state mining and reclamation laws, operators must comply with various federal laws relevant to mining. ​ Geology and Reserves ​ Henderson/Union contains coal resources in three seams ranging in depths from about 100 to 750 feet. The table below summarizes mineral resources as of December 31, 2023, using a cut off thickness of 4.00 feet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quality, Washed, Dry Basis ​ % Recovery ​ Resources (1) Tons (in millions) Thickness (ft) % Ash % Sulfur Btu lbs. SO2 In-Seam ​ ​ ​ ​ ​ ​ ​ ​ ​ Henderson/Union ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Measured Mineral Resources 127.3 4.68 7.72 2.88 13,327 4.32 85.48 ​ Indicated Mineral Resources ​ 227.9 ​ 4.59 ​ 8.01 ​ 2.74 ​ 13,306 ​ 4.12 ​ 87.07 ​ Combined Mineral Resources ​ 355.2 ​ 4.62 ​ 7.90 ​ 2.79 ​ 13,314 ​ 4.19 ​ 86.50 ​ Inferred Mineral Resources 57.5 4.46 7.97 2.56 13,350 3.84 90.42 ​ ​ (1) See updated TRS for Henderson/Union at Exhibit 96.1 to this Annual Report 10-K reflecting the material change to resources during 2023. ​ River View Complex ​ The River View complex is located in Union County, Kentucky at 37°45'37"N, -87°56'42"W and currently has approximately 93,200 underground acres permitted. The complex is composed of the River View and Henderson County mines along with shared preparation, loadout, and other ancillary facilities. The complex is controlled through both fee ownership and leases of the coal. The coal mineral reserves are leased or held for lease to the River View complex almost exclusively by Alliance Resource Properties. The River View complex either owns or controls the surface properties upon which its facilities are located including the preparation plant, refuse areas, mine offices, conveyor systems, shafts and slopes. The base leases are with private owners and generally provide for a term that can be extended until exhaustion of the leased coal. Local infrastructure is as follows: ​ Major Roads: Interstates 69 and US-60, Railroads: None, Airport: Evansville Regional Airport (EVV), Town: Morganfield, Docks: River View on the Ohio River, Water: Union and Henderson County water districts and mine sources, Electricity: Kentucky Utilities (KU), Personnel: Regional. ​ 65 Table of Contents ​ Description ​ The underground mines are currently in production using room-and-pillar methods utilizing a heavy media, float/sink style preparation plant. Exploration continues as needed to fulfill mining and permitting requirements. The complex began production in 2009. All equipment, facilities, infrastructure, and underground development are in good working order and maintained to industry standards. Total book value of the property and any associated plant and equipment for the River View Complex as of December 31, 2023 was $312.7 million. ​ Though there is geographic overlap between the River View complex and the Henderson/Union properties, the reserves and resources of each are associated with different coal seams or, if in the same seam, are separated by existing mine works or geologic features into distinct areas. There is no overlap in the resource / reserve estimation. ​ History ​ Island Creek operated mines in the area and controlled a portion of the property. Under a joint venture, Texas Gas Service also controlled a large interest in the mineral rights. Lastly, Peabody and Patriot operated mines in the area and controlled a smaller portion of the reserves. We consolidated control of the property through multiple transactions from 2005 through 2015. Island Creek operated the Ohio #11 and Uniontown #9 mines to the west of River View. Island Creek also operated the Hamilton #1 and #2 mines to the southwest. Peabody and later Patriot operated the Camp mines and Highland mines adjacent to the complex. Both the WKY9 and WKY11 seams were mined at these locations. In general, all drilling has shown highly consistent coal seams of mineable thickness and quality for the high-sulfur thermal utility market. ​ 66 Table of Contents Encumbrances ​ Our credit facility is secured by, among other things, liens against certain River View complex surface properties and coal leases. Documentation of such liens is of record in the Office of the Union County Clerk. Please read "Item 8. Financial Statements and Supplementary Data—Note 6 – Long-term Debt" for more information on our credit facility. ​ Accounts receivable generated from the sale of coal mined from this property are collateral for our accounts receivable securitization facility, evidenced by financing statements of record in the Office of the Union County Clerk. Please read "Item 8. Financial Statements and Supplementary Data—Note 6 – Long-term Debt" for more information on our accounts receivable securitization facility. ​ The KYDNR, DMP is responsible for review and issuance of all permits relative to coal mining and reclamation activities, and financial assurance of comprehensive environmental protection performance standards related to surface and underground coal mining operations. In addition to state mining and reclamation laws, operators must comply with various federal laws relevant to mining. All applicable permits for underground mining, coal preparation and related facilities, and other incidental activities have been obtained and remain in good standing. ​ Geology and Reserves ​ The River View complex extracts coal underground from the West Kentucky No. 11 and No. 9 seams with depths ranging from 200 to 500 feet across the reserve. The table below summarizes mineral reserves as of December 31, 2023 using a cut off thickness of 4.00 feet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quality, Washed, Dry Basis ​ % Recovery ​ Reserves Tons (in millions) Thickness (ft) % Ash % Sulfur Btu lbs. SO2 In-Seam ​ ​ ​ ​ ​ ​ ​ ​ ​ River View Complex ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Proven Mineral Reserves 169.1 4.69 8.08 3.20 13,191 4.85 87.40 ​ Probable Mineral Reserves 141.3 4.56 8.25 3.18 13,141 4.85 87.25 ​ Total Mineral Reserves ​ 310.4 ​ 4.63 8.16 ​ 3.19 ​ 13,168 ​ 4.85 ​ 87.33 ​ ​ Resources associated with the River View complex are included in the Coal Mineral Resources table above. ​ The River View complex had 204.7 million tons of coal mineral reserves at the end of 2022. The year over year reconciliation is as follows: ​ ​ ​ ​ ​ River View Complex Yearly Reserve Reconciliation (in millions) Tons as of December 31, 2022 204.7 Production ​ (9.9) ​ Mineral Acquisition / Deletion (1) ​ 115.2 ​ Normal Course Adjustments ​ 0.4 ​ Tons as of December 31, 2023 ​ 310.4 ​ ​ (1) See updated TRS for River View complex at Exhibit 96.2 to this Annual Report on Form 10-K reflecting the material change to reserves for 2023. ​ Normal course adjustments are associated with numerous slight changes in the geologic model. ​ Hamilton Mine ​ Hamilton, a longwall mine located in Hamilton County, Illinois at 38°10'12"N, -88°36'47"W, currently has approximately 23,000 underground acres and 1,300 surface acres permitted. The mine property is controlled through both fee ownership and leases of the coal. The coal mineral reserves and resources are leased or held for lease to Hamilton by Alliance WOR Properties, a subsidiary of Alliance Resource Properties. Hamilton either owns or controls the surface properties upon which its facilities are located including the preparation plant, refuse areas, mine offices, conveyor systems, shafts and slopes. The underlying base coal leases are with private owners and are comprised of a large number of leases originally taken by AMAX Coal Company and Old Ben in the mid to late 1970's and early, leases acquired by 67 Table of Contents Consolidation Coal Company in the late 1980's, and subsequent leases taken directly by White Oak Resources, LLC or affiliated companies and/or Alliance WOR Properties. Local infrastructure is as follows: ​ Major Roads: Interstates 64, Railroads: CSX and EVW, Airport: Evansville Regional Airport (EVV), Towns: McLeansboro and Mt. Vernon, Docks: Mount Vernon on the Ohio River, Water: Hamilton County Water District and mine sources, Electricity: Wayne-White Electric Co-op (WWEC), Personnel: Regional. ​ Description ​ The underground mine is currently in production using longwall and room-and-pillar methods utilizing a heavy media, float/sink style preparation plant. Exploration continues as needed to fulfill mining and permitting requirements. The mine began production in 2014. All equipment, facilities, infrastructure, and underground development are in good working order and maintained to industry standards. Total book value of the property and any associated plant and equipment for Hamilton as of December 31, 2023 was $332.4 million. ​ History ​ There were no previous operations on the Hamilton reserves property prior to our predecessor, White Oak Resources LLC, who began construction of the mine in 2011. In general, all drilling has shown highly consistent coal seams of mineable thickness and quality for the high-sulfur thermal utility market for the Herrin and Springfield seams. ​ 68 Table of Contents Encumbrances ​ Our credit facility is secured by, among other things, liens against certain Hamilton surface properties, coal leases and owned coal. Documentation of such liens is of record in the Office of the Hamilton County Clerk. Please read "Item 8. Financial Statements and Supplementary Data — Note 6 – Long-term Debt" for more information on our credit facility. ​ Certain leases originally acquired by Consolidation Coal Company are encumbered by an overriding royalty payable to Sustainable Conservation, Inc. in the amount of the greater of $0.25 per ton or 0.75% of the average sales realization price received per ton, which sums can be credited against approximately $481,000 previously paid to Sustainable Conservation, Inc. for the assignment of these leases. ​ The Illinois Department of Natural Resources, Land Reclamation Division is responsible for review and issuance of all permits relative to coal mining and reclamation activities, and financial assurance of comprehensive environmental protection performance standards related to surface and underground coal mining operations. In addition to state mining and reclamation laws, operators must comply with various federal laws relevant to mining. All applicable permits for underground mining, coal preparation and related facilities and other incidental activities have been obtained and remain in good standing. ​ Geology and Reserves ​ Hamilton extracts coal underground from the Herrin (Illinois No.6) seam with depths ranging from 900 to 1100 feet across the reserve. The table below summarizes mineral reserves as of December 31, 2023 using a cut off thickness of 4.00 feet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quality, Washed, Dry Basis ​ % Recovery ​ Reserves Tons (in millions) Thickness (ft) % Ash % Sulfur Btu lbs. SO2 In-Seam ​ ​ ​ ​ ​ ​ ​ ​ ​ Hamilton County ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Proven Mineral Reserves 54.5 6.38 8.07 2.82 13,414 4.21 86.65 ​ Probable Mineral Reserves 65.3 6.60 7.98 2.85 13,422 4.24 86.77 ​ Total Mineral Reserves ​ 119.8 ​ 6.50 8.02 ​ 2.83 ​ 13,419 ​ 4.23 ​ 86.71 ​ ​ Resources associated with Hamilton County are included in the Coal Mineral Resources table above. ​ The Hamilton mine had 125.9 million tons of coal mineral reserves at the end of 2022. The year over year reconciliation is as follows: ​ ​ ​ ​ ​ Hamilton County Yearly Reserve Reconciliation (in millions) Tons as of December 31, 2022 125.9 Production ​ (5.6) ​ Mineral Acquisition / Deletion ​ 4.1 ​ Mine Plan Adjustment ​ (4.9) ​ Normal Course Adjustments ​ 0.3 ​ Tons as of December 31, 2023 ​ 119.8 ​ ​ Normal course adjustments are associated with numerous slight changes in the geologic model. ​ Gibson South Mine ​ Gibson South is located in Gibson County, Indiana at 38°18'22"N, 87°42'30"W and currently has approximately 23,350 underground acres permitted. The mine property is controlled through both fee ownership and leases of the coal. Leases generally have an initial term with automatic extensions for as long as mining operations are conducted within a described area. Local infrastructure is as follows: ​ Major Roads: Interstates 69 and 64, Railroads: CSX and NS, Airport: Evansville Regional Airport (EVV), Town: Princeton, Docks: Mount Vernon on the Ohio River, 69 Table of Contents Water: Gibson Water, Inc. and well water, Electricity: Western Indiana Energy REMC, Personnel: Regional. Description ​ The underground mine is currently in production using room-and-pillar methods utilizing a heavy media, float/sink style preparation plant. Exploration continues as needed to fulfill mining and permitting requirements. The mine began production in 2014. All equipment, facilities, infrastructure, and underground development are in good working order and maintained to industry standards. Total book value of the property and any associated plant and equipment for Gibson South as of December 31, 2023 was $117.0 million. ​ History ​ In November 1997, pursuant to (a) Assignment of Underground Coal Leases, (b) Partial Assignment of Underground Coal Leases and (c) Special Corporate Warranty Deed, Old Ben conveyed to MAPCO Land & Development Corporation various coal leases and fee coal interests within a large property boundary located in Gibson County, Indiana. MAPCO Land & Development Corporation changed its name to MAPCO Coal Land & Development Corporation, and MAPCO Coal Land & Development Corporation merged into Alliance Properties effective August 4, 1999. ​ After the original Old Ben acquisition, Alliance Properties and Gibson continued to acquire additional coal leases and fee coal interests in the area. In addition, beginning in or around 2006, the leases originally acquired from Old Ben began to expire by their terms, and Alliance Properties/Gibson began a program of either amending the expiring leases or entering into new, direct leases with the coal owners. Alliance Properties merged into Gibson on February 19, 2018. ​ 70 Table of Contents The King's Mine operated to the east and the Wabash Mine operated to the west of the reserve area. In general, all drilling has shown a highly consistent coal seam of mineable thickness and quality for the high-sulfur thermal utility market. ​ Encumbrances ​ Our credit facility is secured by, among other things, liens against certain Gibson surface properties, coal leases and owned coal. Documentation of such liens is of record in the Office of the Recorder of Gibson County, Indiana. Please read "Item 8. Financial Statements and Supplementary Data—Note 6 – Long-term Debt" for more information on our credit facility. ​ Accounts receivable generated from the sale of coal mined from this property are collateral for our accounts receivable securitization facility, evidenced by financing statements of record in the Office of the Recorder of Gibson County, Indiana. Please read "Item 8. Financial Statements and Supplementary Data — Note 6 – Long-term Debt" for more information on our accounts receivable securitization facility. ​ The Indiana Department of Natural Resources, Division of Reclamation is responsible for oversight of active coal mining and reclamation activities, and financial assurance of comprehensive environmental protection performance standards related to surface and underground coal mining operations. In addition to state mining and reclamation laws, operators must comply with various federal laws relevant to mining. All applicable permits for underground mining, coal preparation, and related facilities and other incidental activities have been obtained and remain in good standing. ​ Geology and Reserves ​ Gibson South extracts coal underground from the Springfield (Indiana No.5) seam with depths ranging from 450 to 650 feet across the reserve. The table below summarizes mineral reserves as of December 31, 2023 using a cut off thickness of 4.00 feet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quality, Washed, Dry Basis ​ % Recovery ​ Reserves Tons (in millions) Thickness (ft) % Ash % Sulfur Btu lbs. SO2 In-Seam ​ ​ ​ ​ ​ ​ ​ ​ ​ Gibson South ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Proven Mineral Reserves 35.6 5.96 7.13 2.00 13,477 2.97 94.81 ​ Probable Mineral Reserves 9.6 5.33 8.15 2.51 13,322 3.77 92.82 ​ Total Mineral Reserves ​ 45.2 ​ 5.81 7.34 ​ 2.11 ​ 13,444 ​ 3.14 ​ 94.37 ​ ​ Resources associated with Gibson South are included in the Coal Mineral Resources table above. ​ The Gibson South mine had 49.0 million tons of coal mineral reserves at the end of 2022. The year over year reconciliation is as follows: ​ ​ ​ ​ ​ Gibson South Yearly Reserve Reconciliation (in millions) Tons as of December 31, 2022 49.0 Production ​ (5.3) ​ Mineral Acquisition / Deletion ​ 1.5 ​ Tons as of December 31, 2023 ​ 45.2 ​ ​ Normal course adjustments are associated with numerous slight changes in the geologic model. ​ 71 Table of Contents Tunnel Ridge Mine ​ Tunnel Ridge, located at 40°09'17" N, -80°39'26"W, is an underground longwall mine in the Pittsburgh No. 8 seam of coal, and currently has approximately 22,345 underground acres permitted. The mine property is controlled through both fee ownership and leases of the coal. The coal mined and to be mined by Tunnel Ridge is leased from the Joseph W. Craft III Foundation, the Kathleen S. Craft Foundation, Alliance Resource Properties and third parties. Please read "Item 8. Financial Statements and Supplemental Data - Note 20 – Related-Party Transactions" for additional information on related-party leases. Tunnel Ridge either owns or controls the surface properties upon which its facilities are located, including the preparation plant, refuse areas, mine offices, conveyor systems, shafts and slopes. Local infrastructure is as follows: ​ Major Roads: Interstate 70, Railroads: None, Airport: Pittsburgh International Airport (PIT), Town: Wheeling, Docks: Tunnel Ridge on the Ohio River, Water: Municipal water districts and mine sources, Electricity: American Electric Power (AEP), West Penn Power (WPP) Personnel: Regional. Description ​ The underground mine is currently in production using longwall and room-and-pillar methods utilizing a heavy media, float/sink style preparation plant. Exploration continues as needed to fulfill mining and permitting requirements. The mine began production in 2010. All equipment, facilities, infrastructure, and underground development are in good working order and maintained to industry standards. Total book value of the property and any associated plant and equipment for Tunnel Ridge as of December 31, 2023 was $301.7 million. 72 Table of Contents ​ History ​ Valley Camp Coal Company operated mines on the property prior to Tunnel Ridge's operations. In general, all drilling has shown a highly consistent coal seam of mineable thickness and quality for the high-sulfur thermal utility market. ​ Encumbrances ​ Our credit facility is secured by, among other things, liens against certain Tunnel Ridge surface properties, coal leases and owned coal. Documentation of such liens is of record in the Office of the County Commission of Ohio County, West Virginia and the Office of the Recorder of Deeds of Washington County, Pennsylvania. Please read "Item 8. Financial Statements and Supplementary Data — Note 6 – Long-term Debt" for more information on our credit facility. ​ Accounts receivable generated from the sale of coal mined from this property are collateral for our accounts receivable securitization facility, evidenced by financing statements of record in the Office of the County Commission of Ohio County, West Virginia and the Office of the Recorder of Deeds of Washington County, Pennsylvania. Please read "Item 8. Financial Statements and Supplementary Data — Note 6 – Long-term Debt" for more information on our accounts receivable securitization facility. ​ Tunnel Ridge is located on the West Virginia / Pennsylvania State boundary, operating in each state. As such, regulatory requirements must be met pertaining to mining facilities located in each state. ​ For operations in West Virginia, the WVDEP is the regulatory authority over mining activities. Within the WVDEP, the Division of Mining and Reclamation is responsible for review and issuance of all permits relative to coal mining and reclamation activities, and financial assurance of comprehensive environmental protection performance standards related to surface and underground coal mining operations. ​ For operations in Pennsylvania, the PADEP is the regulatory authority over mining activities. Within the PADEP, the Bureau of District Mining Operations is responsible for review and issuance of all permits relative to coal mining and reclamation activities, and financial assurance of comprehensive environmental protection performance standards related to surface and underground coal mining operations. ​ Geology and Reserves ​ Tunnel Ridge extracts coal underground from the Pittsburgh No.8 seam with depths ranging from 300 to 975 feet across the reserve. The table below summarizes mineral reserves as of December 31, 2023 using a cut off thickness of 4.00 feet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quality, Washed, Dry Basis ​ % Recovery ​ Reserves Tons (in millions) Thickness (ft) % Ash % Sulfur Btu lbs. SO2 In-Seam ​ ​ ​ ​ ​ ​ ​ ​ ​ Tunnel Ridge ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Proven Mineral Reserves 64.5 7.12 7.92 3.10 13,711 4.52 67.88 ​ Probable Mineral Reserves 53.7 7.26 8.30 3.49 13,618 5.13 68.06 ​ Total Mineral Reserves ​ 118.2 ​ 7.18 8.09 ​ 3.28 ​ 13,669 ​ 4.79 ​ 67.96 ​ ​ Resources associated with Tunnel Ridge are included in the Coal Mineral Resources table above. ​ 73 Table of Contents The Tunnel Ridge mine had 120.0 million tons of coal mineral reserves at the end of 2022. The year over year reconciliation is as follows: ​ ​ ​ ​ ​ Tunnel Ridge Yearly Reserve Reconciliation (in millions) Tons as of December 31, 2022 120.0 Production ​ (7.7) ​ Mineral Acquisition / Deletion ​ (1.2) ​ Mine Plan Adjustment ​ 6.8 ​ Normal Course Adjustments ​ 0.3 ​ Tons as of December 31, 2023 ​ 118.2 ​ ​ OIL & GAS RESERVES ​ Summary of Oil & Gas Reserves ​ Our mineral interests are primarily located in three basins, which are also our areas of focus for future development. These include the Permian (Delaware and Midland), Anadarko (SCOOP/STACK) and Williston (Bakken) Basins. At December 31, 2023, we had 49,794 developed and undeveloped net acres held at a weighted average royalty of 17.0%. Our net acres standardized to 1/8th royalty equates to 67,745 net royalty acres, including 3,969 net royalty acres owned through our equity interest in AllDale III. ​ The following table presents our estimated net proved oil & gas reserves, including our share of reserves attributable to our equity interest in AllDale III, as of December 31, 2023 based on the reserve report prepared by our internal engineering team and reserve information provided by AllDale III. The reserve report and reserve information have been prepared in accordance with the rules and regulations of the SEC. All of our proved reserves are located in the continental United States. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2023 ​ ​ Crude Oil Natural Gas Natural Gas Liquids Total ​ (MBbl) (MMcf) (MBbl) (MBOE) (2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated proved developed reserves ​ ​ 7,754 ​ ​ 45,684 ​ ​ 5,485 ​ ​ 20,854 Estimated proved undeveloped reserves ​ ​ 1,599 ​ ​ 5,839 ​ ​ 868 ​ ​ 3,440 Total estimated proved reserves (1) ​ ​ 9,353 ​ ​ 51,523 ​ ​ 6,353 ​ ​ 24,294 (1) Proved reserves of approximately 1,780 MBOE were attributable to noncontrolling interests as of December 31, 2023. (2) Natural gas reserve volumes are converted to BOE based on a 6:1 ratio: 6 Mcf of natural gas converts to one BOE. ​ Estimates of reserves as of December 31, 2023 were prepared using product prices equal to the unweighted arithmetic average of the first-day-of-the-month market price for each month in the period from January through December 2023. The average realized product prices weighted by production over the remaining lives of the properties are $77.61/Bbl for oil, $1.55/Mcf of natural gas and $22.63 per barrel of NGL. These prices are adjusted for energy content, associated average differential and transportation deducts by producing area to arrive at the net realized prices by product. For 2023, NGL prices averaged approximately 33% of the posted oil prices during the course of the year with an additional $3.18/Bbl deducted for transportation costs. ​ The following table summarizes our changes in proved undeveloped reserves (in MBOE): ​ ​ ​ ​ ​ ​ Beginning balance, January 1, 2023* ​ ​ 3,795 ​ Acquisitions of proved undeveloped reserves ​ ​ 38 ​ Transfers of PUDs to estimated proved developed ​ ​ (1,448) ​ Extensions and discoveries ​ ​ 2,462 ​ Revisions of previous estimates ​ ​ (1,407) ​ Ending balance, December 31, 2023 ​ ​ 3,440 ​ * Recast to reflect the JC Resources Acquisition as if we, rather than JC Resources, acquired the mineral interests in 2019. Please see "Item 8. Financial Statement and Supplemental Data—Note 1 – Organization and Presentation and Note 3 – Acquisitions" for more information. 74 Table of Contents ​ As a mineral interest owner we have no transparency into or control over the Operators' investments and operational progress to convert PUDs to proved developed producing reserves. We do not incur any capital expenditures or lease operating expenses in connection with the development of our PUDs, which costs are borne entirely by the Operators. As a result, during the year ended December 31, 2023, we did not have any expenditures to convert PUDs to proved developed producing reserves. PUDs that have not been developed within two years of permitting are reviewed and removed from proved reserves as necessary. As of December 31, 2023, approximately 14.16% of our total proved reserves were classified as PUDs. ​ Evaluation and Review of Reserves ​ Numerous uncertainties are inherent in estimating reserve volumes and values, and the estimates are subject to change as additional information becomes available. The reserves actually recovered and the timing of production of the reserves may vary significantly from the original estimates. ​ Under SEC rules, proved reserves are those quantities of oil & gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible–from a given date forward, from known reservoirs and under existing economic conditions, operating methods and government regulations–prior to the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. If deterministic methods are used, the SEC has defined reasonable certainty for proved reserves as a "high degree of confidence that the quantities will be recovered." All of our proved reserves as of December 31, 2023 were estimated using a deterministic method. The estimation of reserves involves two distinct determinations. The first determination results in the estimation of the quantities of recoverable oil & gas and the second determination results in the estimation of the uncertainty associated with those estimated quantities in accordance with the definitions established under SEC rules. The process of estimating the quantities of recoverable oil & gas reserves relies on the use of certain generally accepted analytical procedures. These analytical procedures fall into three broad categories or methods: ​ (1) performance-based methods, (2) volumetric-based methods and (3) analogy. ​ These methods may be used singularly or in combination by the reserve evaluator in the process of estimating the quantities of reserves. The proved reserves for our properties were estimated by performance methods, analogy or a combination of both methods. Performance methods include, but may not be limited to, decline curve analysis, which utilized extrapolations of available historical production data. The analogy method was used where there were inadequate historical performance data to establish a definitive trend and where the use of production performance data as a basis for the reserve estimates was considered to be inappropriate. ​ To estimate economically recoverable proved reserves and related future net cash flows, our engineering team considered many factors and assumptions, including the use of reservoir parameters derived from geological, geophysical and engineering data which cannot be measured directly, economic criteria based on current costs and the SEC pricing requirements and forecasts of future production rates. To establish reasonable certainty with respect to our estimated proved reserves, the technologies and economic data used in the estimation of our proved reserves included production and well test data, downhole completion information, geologic data, electrical logs, and radioactivity logs. ​ Excluding our share of proved reserves held by AllDale III, our 2023 year-end estimate of proved reserves were prepared by our internal engineering team. Our engineering team works to ensure the integrity, accuracy, and timeliness of the data used to calculate our estimated proved reserves. Our proved resource estimates were audited by CGA. Our engineering team met with CGA periodically during the period covered by the above referenced reserve report to discuss the assumptions and methods used in the reserve estimation process. Our engineering team provided historical information to CGA for our properties, such as oil & gas production, well test data, and realized commodity prices. Our engineering team also provided ownership interest information with respect to our properties. Our internal petroleum engineer, primarily responsible for overseeing the petroleum reserves preparation, has over 20 years of engineering and operations experience in the oil & gas sector and a Bachelor of Science in Petroleum Engineering. ​ The preparation of our proved reserve estimates are completed in accordance with our internal control procedures. These procedures, which are intended to ensure reliability of reserve estimations, include the following: 75 Table of Contents ​ ● review and verification of historical data, which is based on actual production as reported by the Operators; ● verification of property ownership by our land department; ● review of all our reported proved reserves semi-annually including the review of all significant reserve changes and proved undeveloped reserves additions by our internal petroleum engineer; ● internally prepared reserve estimates compared to reserves audit by CGA; ● review of changes in reserves semi-annually by our internal petroleum engineer and by senior management; and ● no employee ' s compensation is tied to the amount of reserves booked. ​ CGA, an independent third-party petroleum engineering firm, does not own an interest in any of our properties and is not employed on a contingent basis. When compared on a well-by-well basis, some of our estimates are greater and some are less than the CGA estimates. CGA is satisfied with our methods and procedures used to prepare the December 31, 2023 reserve estimates and future revenue, and noted nothing of an unusual nature that would cause CGA to take exception with the estimates, in the aggregate, prepared by us. CGA's audit report with the respect to our proved reserve estimates as of December 31, 2023 is included as an exhibit to this Annual Report on Form 10-K. ​ CGA was founded in 1961 and performs consulting petroleum engineering services under Texas Board of Professional Engineers Registration No. F-693. Within CGA, the technical person primarily responsible for auditing the estimates meets or exceed the education, training, and experience requirements set forth in the Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information promulgated by the Society of Petroleum Engineers and is proficient in judiciously applying industry-standard practices to engineering and geoscience evaluations as well as applying SEC and other industry reserves definitions and guidelines. ​ Acreage Concentration ​ Our mineral interests, which include both proved reserves discussed above and unproved reserves, are primarily located in three basins, which are also our areas of focus for future operator development. These include the Permian (Delaware and Midland), Anadarko (SCOOP/STACK) and Williston (Bakken) Basins. Below is a chart reflecting our gross, net mineral and net royalty acreage associated with our mineral interests in each of our primary basins as of December 31, 2023. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Developed Acreage ​ Undeveloped Acreage ​ Gross Net Mineral Net Royalty Gross Net Mineral Net Royalty Basin ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Permian Basin ​ ​ 378,510 ​ ​ 11,114 ​ ​ 14,894 ​ ​ 517,804 ​ ​ 15,204 ​ ​ 20,350 ​ Anadarko Basin ​ ​ 179,993 ​ ​ 6,489 ​ ​ 9,199 ​ ​ 295,884 ​ ​ 10,667 ​ ​ 15,112 ​ Williston Basin ​ ​ 153,772 ​ ​ 2,541 ​ ​ 3,363 ​ ​ 84,118 ​ ​ 1,390 ​ ​ 1,849 ​ Other ​ ​ 28,174 ​ ​ 1,027 ​ ​ 1,296 ​ ​ 37,363 ​ ​ 1,362 ​ ​ 1,682 ​ Total ​ ​ 740,449 ​ ​ 21,171 ​ ​ 28,752 ​ ​ 935,169 ​ ​ 28,623 ​ ​ 38,993 ​ ​ 76 Table of Contents Oil & Gas Production Prices and Production Costs ​ For the year ended December 31, 2023, 45.5% of our production and 79.4% of our oil & gas revenues were related to oil production and sales, respectively. The following table sets forth information regarding production of oil & gas including our equity investment in AllDale III and certain price and cost information for each of the periods indicated: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2023 ​ 2022* ​ 2021* Production: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Oil (MBbls) ​ ​ 1,462 ​ ​ 1,104 ​ ​ 929 ​ Natural gas (MMcf) ​ ​ 6,161 ​ ​ 5,226 ​ ​ 3,881 ​ Natural gas liquids (MBbls) ​ ​ 726 ​ ​ 541 ​ ​ 402 ​ BOE (MBbls) ​ ​ 3,215 ​ ​ 2,516 ​ ​ 1,978 ​ Average Realized Prices: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Oil (per Bbl) ​ $ 77.40 ​ $ 94.76 ​ $ 66.19 ​ Natural gas (per Mcf) ​ $ 2.03 ​ $ 6.29 ​ $ 3.86 ​ Natural gas liquids (per Bbl) ​ $ 23.15 ​ $ 38.53 ​ $ 28.58 ​ BOE (MBbls) ​ $ 44.32 ​ $ 62.94 ​ $ 44.47 ​ Unit cost per BOE: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Production and ad valorem taxes ​ $ 4.37 ​ $ 5.61 ​ $ 4.54 ​ * Recast to reflect the JC Resources Acquisition as if we, rather than JC Resources, acquired the mineral interests in 2019. Please see "Item 8. Financial Statement and Supplemental Data—Note 1 – Organization and Presentation and Note 3 – Acquisitions" for more information. ​ Productive Wells ​ As of December 31, 2023, 10,795 gross productive horizontal wells and 5,769 gross productive vertical wells were located on the acreage in which we have a mineral interest. Of our productive horizontal wells, 992 are considered natural gas wells, while the remaining 9,803 primarily produce oil. Productive wells consist of producing wells and wells capable of production, including natural gas wells awaiting pipeline connections to commence deliveries and oil wells awaiting connection to production facilities. We do not own any material working interests in any wells. Accordingly, we do not own any net wells. ​ Drilling Results ​ As a holder of mineral interests, we generally are not provided with information as to whether any wells drilled on the acreage associated with our mineral interests are classified as exploratory or as developmental wells. We are not aware of any dry holes drilled on the acreage associated with our mineral interests during the relevant period. ​ ​