# US 8,740,310 B2 · Mining method for co-extraction of non-combustible ore and mine methane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,740,310 B2 - Document ID: US8740310B2 - Status: Granted - Kind: B2 - Application number: 12/487,802 - Filed: 2009-06-19 - Published: 2009-12-24 - Granted: 2014-06-03 - Earliest claimed: 2008-06-20 - Assignees: Solvay Chemicals, Inc. - Applicants: Larry Refsdal; Ronald O. Hughes; Bryan M. Mortimer; Richard A. Hodgson; Joseph A. Vendetti - Inventors: Larry Refsdal; Ronald O. Hughes; Bryan M. Mortimer; Richard A. Hodgson; Joseph A. Vendetti - Web page: https://patentgrep.com/patent/US8740310B2 ## CPC - E21B 43/006: {Production of coal-bed methane (E21B43/243 takes precedence)} - E21C 41/22: for ores, e.g. mining placers - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - E21C: MINING OR QUARRYING ## Abstract A method for co-extracting non-combustible ore (e.g., trona) and methane from an underground formation comprising at least one methane-bearing layer and a non-combustible ore bed having a rock roof, comprising: providing a well having a downhole end positioned above the ore bed roof; mining an ore region from an initial cavity and removing the mined ore, thereby creating a subsequent cavity; advancing the mining step to another ore region from the subsequent cavity; allowing the roof of the initial cavity to cave so as to create a gob; repeating the mining, advancing and caving steps, the caving being effective in generating fluid communication between the gob and the well downhole end and in fracturing the methane-bearing layer so as to release methane into the gob; and recovering a gob gas comprising released methane through the well to the surface. ## Claims ### Claim 1 A mining method for co-producing non-combustible ore and methane from an underground formation, said underground formation comprising at least one methane-bearing layer and an ore bed to be mined comprising non-combustible ore and having a roof above which rock material is present, the method comprising: drilling a least one well from the earth's surface towards the ore bed, said well having a downhole end positioned above the ore bed roof, said downhole end of the well not being in contact with the ore bed to be mined; providing at least an initial cavity into the formation, the initial cavity giving access to an initial working face of the ore bed to be mined; mining an ore region from the initial working face and removing the mined ore, thereby creating a subsequent mined-out cavity with a new subsequent working face; advancing the mining step to another ore region from the subsequent working face; allowing the roof of the initial cavity to cave so as to create a gob containing at least rock rubbles; repeating the mining, advancing and caving steps, in a manner effective to cause fracture of the methane-bearing layer and release of mine methane into the gob, and to further establish fluid communication between the gob and the downhole end of the well; recovering a gob gas comprising between 25% and 98% methane through the well to the surface; and combusting at least a portion of said recovered gob gas comprising said methane in a flare or in a surface refinery where the mined ore is processed. ### Claim 2 (depends on 1) The method according to claim 1 wherein the downhole end of the well is situated at least 3 meters above the roof of the ore bed. ### Claim 3 (depends on 1) The method according to claim 1 wherein the at least one well is a vertical well, and wherein the downhole end of the vertical well comprises a slotted casing. ### Claim 4 (depends on 3) The method according to claim 3 wherein the slotted casing in the well downhole end has a length of between 30 and 100 meters. ### Claim 5 (depends on 1) The method according to claim 1 wherein any cavity which provides a working face to be mined is provided with roof supports, and wherein the supports are incrementally advanced into any subsequent mined-out cavity. ### Claim 6 (depends on 1) The method according to claim 1 wherein the mining step comprises long-wall mining. ### Claim 7 (depends on 6) The method according to claim 6 wherein the initial cavity is an initial horizontal mined-out cavity, wherein two substantially parallel passages are created into the underground formation, connected by the initial horizontal mined-out cavity, thereby defining an ore panel having the length of the parallel passages, the initial working face of the initial horizontal mined-out cavity extending from one parallel passage to the other, and wherein two wells are drilled offset from the axial centerline of the ore panel from a surface location located between the two parallel passages. ### Claim 8 (depends on 7) The method according to claim 7 wherein the two wells are separated from each other by a distance comprised between one third and two thirds of the length of the passages. ### Claim 9 (depends on 1) The method according to claim 1 wherein at least a portion of the recovered gob gas comprising released methane is directed to the surface refinery where the mined ore is processed, so that at least a portion of said recovered gob gas comprising released methane is used as an energy source in the ore processing refinery. ### Claim 10 (depends on 1) The method according to claim 1 wherein at least one methane-bearing layer is positioned above the non-combustible ore bed. ### Claim 11 (depends on 1) The method according to claim 1 wherein at least one methane-bearing layer is positioned below the non-combustible ore bed. ### Claim 12 (depends on 1) The method according to claim 1 wherein the non-combustible ore comprises trona. ### Claim 13 (depends on 12) The method according to claim 12 wherein the mined trona is calcined in a calciner fueled by at least a portion of the recovered gob gas comprising released methane. ### Claim 14 (depends on 1) A method for reducing the green house effect during mining of a non-combustible ore with co-production of mine methane from an underground formation, said method comprising carrying out the mining method according to claim 1, wherein said underground formation comprising at least one methane-bearing layer and a non-combustible ore bed comprising trona, and wherein at least a portion of the mine methane is recovered from the gob via the well and combusted. ### Claim 15 (depends on 1) The method according to claim 1 wherein a tubular casing is placed in an upper part of the well after its drilling to ensure smooth flow of the gob gas, wherein the downhole end of the well comprises a slotted casing, and wherein the slotted casing of the well downhole end is moveable, is not fixed to the casing of the well upper part, and is positioned free-standing at the bottom of the well to allow relative movement of the slotted casing with respect to the well upper part. ### Claim 16 (depends on 1) The method according to claim 1 wherein the downhole part of the well passes through an overlying methane-bearing layer. ### Claim 17 (depends on 1) The method according to claim 1 wherein the downhole end of the well is positioned at an intermediate depth between an overlying methane-bearing layer and the roof of the ore bed being mined. ### Claim 18 (depends on 1) The method according to claim 1 wherein the gob gas flow is facilitated by a pump or exhauster, and wherein the gob gas flow output from the well is at least about 200,000 ft3/day. ### Claim 19 (depends on 18) The method according to claim 18 wherein at least a portion of the recovered gob gas comprising released methane is directed to a surface refinery where the mined ore is processed, so that at least a portion of said recovered gob gas comprising released methane is used as an energy source in the ore processing refinery. ### Claim 20 (depends on 1) The method according to claim 1 wherein the gob gas flow is facilitated by a methane-powered engine vacuum pump or exhauster, and wherein a methane-powered engine coupled to the vacuum pump or exhauster is powered by at least a portion of the released methane. ### Claim 21 A mining method for co-producing non-combustible ore and methane from an underground formation, said underground formation comprising at least one methane-bearing layer and an ore bed to be mined comprising non-combustible ore and having a roof above which rock material is present, the method comprising: drilling a least one well from the earth's surface towards the ore bed, said well having a downhole end positioned above the ore bed roof, said downhole end of the well not being in contact with the ore bed to be mined; providing at least an initial cavity into the formation, the initial cavity giving access to an initial working face of the ore bed to be mined; solution mining an ore region from the initial working face, said solution mining step comprising: injecting a solvent into the initial cavity to expose the initial working face in a manner effective to dissolve a desired mineral solute from the exposed ore, and to form a liquor comprising dissolved desired mineral solute, said dissolution being effective in forming a subsequent mined-out cavity and in advancing the initial working face to a subsequent working face, repeating the solvent injection and dissolution in a manner effective to enlarge the subsequent mined-out cavity by dissolving more of the desired mineral solute from the subsequent working face of the solvent-exposed ore, and removing the mined ore by flowing the liquor to the surface; allowing the caving of overburden ore and rock nibbles into the initial and subsequent mined-out cavities to form a gob and to fracture the at least one methane-bearing layer to release methane into the gob, and to further establish fluid communication between the gob and the downhole end of the well; and recovering a gob gas comprising released methane through the well to the surface.