Solution mining using subterranean drilling techniques
A method of solution mining a subterranean mineral ore deposit such as trona ore in which a borehole is drilled from a subterranean mechanically-worked mineral ore mining operation to connect a mineral ore bed to be solution mined, using subterranean drilling apparatus located proximate to the mechanically-worked mineral ore mining operation. The mineral ore bed is isolated from the mechanically-worked mineral ore mining operation by passage of the drilled borehole through an impermeable layer adjacent to the mineral ore bed to be solution mined. The mineral ore bed is then solution-mined using a mining solvent introduced into the mineral ore bed to solubilize the mineral and form a mining solution, and the resulting mining solution is withdrawn from the mineral ore bed.
1. A method of solution mining a subterranean mineral ore deposit comprising connecting (i) an existing subterranean mechanically-worked mineral ore mining operation and (ii) a mineral ore bed region to be solution mined, with a borehole drilled into the mineral ore bed region to be solution mined using subterranean drilling apparatus located proximate to the existing subterranean mechanically-worked mineral ore mining operation;
isolating the mineral ore bed region to be solution mined from the existing subterranean mechanically-worked mineral ore mining operation by passage of the drilled borehole from the existing subterranean mechanically-worked mineral ore mining operation through an insoluble impermeable layer adjacent to the mineral ore bed to be solution mined and then into the mineral ore bed region having solution mineral ore values to be solution mined to form an isolated mineral ore bed region so that mining solution is prevented from flowing back into the existing subterranean mechanically-worked mineral ore mining operation;
solution mining the isolated mineral ore bed region using a mining solvent introduced into the mineral ore bed region to be solution mined to solubilize the mineral and form a mining solution, wherein the mineral ore bed to be solution mined is the same mineral ore bed being worked by the mechanically-worked mineral ore mining operation; and
withdrawing mining solution from the solution-mined mineral ore bed region.
2. The method of claim 1 wherein the subterranean mineral ore comprises a mineral solubilizable in a mining solvent selected from the group consisting of water, aqueous alkali solutions and aqueous acid solutions.
3. The method of claim 1 wherein the subterranean mineral ore to be solution mined comprises a mineral selected from the group consisting of trona, wegscheiderite, nahcolite and mixtures of these minerals.
4. The method of claim 3 wherein the mining solvent is selected from the group consisting of water and aqueous alkali solutions.
5. The method of claim 1 wherein the subterranean mineral ore to be solution mined comprises a mineral selected from the group consisting of potash, halite, uranium, copper and gold.
6. The method of claim 1 wherein the impermeable layer comprises shale.
7. The method of claim 1 wherein the drilled borehole, connecting the mineral ore bed to be solution mined and the mechanically-worked mineral ore mining operation, (i) is initiated directly into the impermeable layer proximate to the mechanically-worked mineral ore mining operation and (ii) is then directed into the mineral ore bed region to be solution mined.
8. The method of claim 1 wherein the mineral ore bed to be solution mined is located in a mineral ore bed that is different from the mineral ore bed being worked by the mechanically-worked mineral ore mining operation and, further, wherein the two mineral ore beds are separated by at least one intervening impermeable layer.
9. The method of claim 1 wherein the drilled borehole passing through the insoluble impermeable layer and connecting the mineral ore bed region to be solution mined and the mechanically-worked mineral ore mining operation is at least 50 feet in length in the portion of drilled borehole passing through the impermeable layer.
10. The method of claim 1 wherein the mineral ore bed region to be solution mined is located at least 200 feet from the drilled borehole in the existing subterranean mechanically-worked mineral ore mining operation.
11. The method of claim 1 wherein the drilled borehole is cased in at least a portion of a drilled borehole extending from the drilling initiation point.
12. The method of claim 1 wherein the drilled borehole is cased from the drilled borehole in the existing subterranean mechanically-worked mineral ore mining operation through the insoluble impermeable layer.
13. The method of claim 1 wherein the drilled borehole connecting the existing subterranean mechanically-worked mineral ore mining operation and the mineral ore region to be solution mined is updip from the existing subterranean mechanically-worked mineral ore mining operation.
14. The method of claim 1 wherein the subterranean mineral ore bed region to be solution mined is an abandoned section of a previously mechanically-worked mineral ore bed.
15. The method of claim 1 wherein injection of the mining solvent is carried out through the drilled borehole.
16. The method of claim 1 wherein withdrawal of the mining solution is carried out through the drilled borehole.
17. The method of claim 1 wherein the withdrawn mining solution is pumped to the surface for further processing.
18. The method of claim 1 wherein injection of the mining solvent is effected via the drilled borehole and recovery of the mining solution from the solution mined ore deposit is effected via a separately-drilled different borehole.
19. The method of claim 1 which further comprises injecting of the mining solvent via at least one injection well drilled from the earth's surface into the region of mineral ore deposit to be solution mined and recovering the resultant mining solution from the solution-mined ore deposit via the drilled borehole.
20. The method of claim 1 , wherein the mineral ore deposit is trona.