摘要:
A method for in situ solution mining of a mineral from an underground evaporite stratum using a set of wells in fluid communication with at least one mineral cavity with some wells operated in solvent injection mode and other wells operated in brine production mode and optionally with some inactive wells, comprising switching the operation mode of one or more wells. The evaporite mineral preferably comprises trona. The at least one cavity is preferably formed by lithological displacement of the evaporite stratum at a weak interface with an underlying insoluble stratum by application of a lifting hydraulic pressure. The extracted brine can be processed to make valuable products such as soda ash and/or any derivatives thereof, rock salt, or potash. This method can provide more uniform dissolution of mineral in the cavity, can minimize flow channeling, can minimize sodium bicarbonate blinding for solution mining of incongruent trona ore, and/or may avoid uneven deposit of insolubles.
摘要:
Methods for sealing undesirable transverse fractures enlarged and/or created during lithological displacement of an underground water-soluble evaporite stratum by hydraulic pressure greater than overburden pressure at an evaporite/non-evaporite strata interface, comprising injecting and maintaining a sealing agent into these undesirable fractures to form a solidified matter in situ and ultimately seal them, while forming a main free surface at the interface suitable for initiating solution mining of the evaporite stratum. The solidified matter may be crystallized, precipitated, compacted, agglomerated, cross-linked, coagulated, water-swollen, and/or cemented matter, or may include a wall-building matter with the mineral on fracture faces. The sealing agent may comprise at least one component of the mineral and/or the non-evaporite. The evaporite stratum is preferably a trona stratum overlying an oil shale stratum. The sealing agent may comprise dissolved and/or solid trona, trona tailings particles, and/or water-swelling particles.
摘要:
A lithological displacement of an underground evaporite mineral stratum from an underlying non-evaporite stratum comprising the application of a lifting hydraulic pressure of a fluid at a weak interface between the strata, resulting in lifting the overburden above the interface, separating the evaporite stratum from the underlying non-evaporite stratum and thus forming a mineral free-surface. The lifting hydraulic pressure is greater than the overburden pressure. The formed mineral free-surface is accessible for dissolution by a solvent. The fluid used for lifting may comprise a solvent suitable to dissolve the mineral. The evaporite mineral stratum preferably comprises trona, nahcolite, wegscheiderite, or combinations thereof.
摘要:
Batch initiation and/or exploitation phases of in situ solution mining of a mineral from an underground evaporite mineral stratum. The initiation phase may comprise a lifting step which employs a lithological displacement (lifting) of this stratum from an underlying non-evaporite stratum with application at the strata interface of a lifting hydraulic pressure greater than overburden pressure by a solvent suitable to dissolve the mineral; a soaking step for dissolution of mineral upon contact with stationary solvent, and a brine extraction step. The method may further comprise one or more exploitation phases carried out after the initiation phase. The exploitation phase may comprise a partial filing or filling step with the same solvent or different solvent than during lifting, another soaking step, and another brine extraction step. The lifting, cavity partial filing/filling, and brine extraction steps are being discontinuous. The evaporite mineral stratum preferably comprises trona.
摘要:
A method for in situ solution mining of a mineral from an underground evaporite stratum using a set of wells in fluid communication with at least one mineral cavity with some wells operated in solvent injection mode and other wells operated in brine production mode and optionally with some inactive wells, comprising switching the operation mode of one or more wells. The evaporite mineral preferably comprises trona. The at least one cavity may be formed by directionally drilled uncased boreholes or by lithological displacement of the evaporite stratum at a weak interface with an underlying insoluble stratum by application of a lifting hydraulic pressure to create an interfacial gap. The extracted brine can be processed to make valuable products such as soda ash and/or any derivatives thereof. This method can provide more uniform dissolution of mineral in the cavity, minimize flow channeling, minimize sodium bicarbonate blinding for solution mining of incongruent trona ore, and/or may avoid uneven deposit of insolubles.
摘要:
A method for in situ solution mining of trona in which an aqueous solvent dissolves trona and forms a brine, which comprises: applying a hydraulic pressure greater than the overburden pressure at an interface between trona roof and overburden to lithologically displace the overburden from the trona roof and form a gap; flowing a liquid settable and/or sealing composition into such interface gap and allowing such composition to solidify inside such gap to form a water-impermeable and optionally gas-impermeable barrier inside. This technique should limit contamination from the overburden; should seal or plug fractures transversing the trona roof; should prevent water infiltration from overburden; and/or should minimize gas migration into the overburden from the cavity. The lithological displacement whereby the interface gap is formed may be carried out at the same time as the composition is flowed inside the gap being formed.
摘要:
A method for in situ solution mining of a mineral from an underground evaporite stratum using a set of wells in fluid communication with at least one mineral cavity with some wells operated in solvent injection mode and other wells operated in brine production mode and optionally with some inactive wells, comprising switching the operation mode of one or more wells. The evaporite mineral preferably comprises trona. The at least one cavity may be formed by directionally drilled uncased boreholes or by lithological displacement of the evaporite stratum at a weak interface with an underlying insoluble stratum by application of a lifting hydraulic pressure to create an interfacial gap. The extracted brine can be processed to make valuable products such as soda ash and/or any derivatives thereof. This method can provide more uniform dissolution of mineral in the cavity, minimize flow channeling, minimize sodium bicarbonate blinding for solution mining of incongruent trona ore, and/or may avoid uneven deposit of insolubles.