Abstract: A method of treating a subterranean formation which has undergone an in situ leaching operation which utilized an ammonium carbonate and/or bicarbonate lixiviant. In such a leach operation, ammonium ions will absorb into the clay in the formation and will present a threat of contamination to any ground waters that may be present in the formation. The present method involves flushing the formation with a strong, alkaline solution, e.g., sodium or calcium hydroxide, to convert the ammonium ions to ammonia which is easily carried from the formation by the alkaline solution. The alkaline solution is modified by adding a monovalent metal salt, e.g., sodium chloride, which prevents the clay from swelling which decreases the permeability of the formation. After substantially all of the ammonium ions are removed, the formation is then flushed with water to remove any alkaline solution which may remain in the formation.

Abstract: An improved method of solution well mining is provided which, among other advantages, enhances the injectivity of the wells and eliminates the need for underreaming and the use of well screens. In solution well mining, a leaching solution is pumped into an injection well so as to flow through a mineralized zone to a plurality of production wells, the solution which contains the mineral to be recovered being pumped out of the production wells. The invention provides for using a high pressure water jet to perforate the cemented casings of the well so as to, inter alia, enhance injectivity and provide sand control. The perforations are arranged in a preselected nonuniform pattern in the production well, with the density being the greatest at the bottom of the zone, so as to promote uniform flow of the solution.

Abstract: An underground carbonaceous deposit containing other mineral values is burned in situ. The underground hot zone is cooled down to temperature below the boiling point of a leaching solution. The leaching solution is percolated through the residial ash, with the pregnant solution recovered for separation of the mineral values in surface facilities.

Abstract: The present invention relates to a method for the restoring of an underground reservoir subsequent to the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to the introduction of a sulfate reducing bacteria into a subterranean formation to decrease the total dissolved solids level of the reservoir present therein.

Abstract: The present invention relates to an improved method for the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to an improved method which enhances significantly the recovery of a mineral via solution mining with an injection and production well from a subterranean formation which contains the mineral in a zone of low permeability having a zone of higher permeability both above and below it. The improvement comprises locating an injection well in one zone of high permeability and a production well in the other zone of high permeability.

Abstract: In a process for recovering liquid and gaseous products from an in situ oil shale retort containing a fragmented permeable mass of particles containing oil shale, a heated zone is established in an upper portion of the fragmented mass. For a period of normal retorting operation, an oxygen containing gas is introduced to the fragmented mass on the trailing side of the heated zone at a sufficient rate for advancing the heated zone downwardly through the fragmented mass and liquid products and a relatively lean off gas containing gaseous products are withdrawn from the bottom of the retort. Thereafter, for a period of post-retorting operation, the introduction of gas to the fragmented mass is reduced to a rate such that a relatively rich off gas is withdrawn from the retort. The rich withdrawn off gas preferably has a heating value of at least about 75 BTU/SCF.

Abstract: Carbon dioxide is admixed with water to form a carbonic acid solution for use as a leaching solution for extraction of uranium by solution mining. An oxidizing agent is also present in the solution.

Abstract: A method of controlling calcite in an in situ leaching operation by retarding the growth of calcite crystals in the lixiviant only for the resident time that the lixiviant is in a critical area of the leach circuit and then allowing the calcite to precipitate from the lixiviant in a noncritical area. A chemical inhibitor, e.g., sodium hexametaphosphate, is added to the lixiviant as the lixiviant enters a critical area, e.g., from the bottom of a production well to surface processing equipment. The inhibitor is added to the lixiviant in an amount sufficient only to retard calcite precipitation while the lixiviant moves through a critical area but not to seriously impede calcite precipitation after the lixiviant exits the critical area.

Abstract: There is disclosed an improved system method for in situ extraction of mineral values from subterranean deposits of ores of the oxide; carbonate; sulphide, or other type ores which contain sought-for metal values and which evolve gas when reacted with suitable chemicals in solution and/or gaseous form. The invention is particularly applicable to in situ mining of the previously found types of copper, nickel, manganese, etc. oxide, carbonate, and sulphide ores and the like; and especially features conservation of energy which otherwise would be wasted.

Abstract: The present invention relates to an improved method for the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to an improved method which enhances significantly the recovery of a mineral from a subterranean formation via solution mining. The improvement comprises injecting oxidant into said formation via a production well simultaneously with the injection of solvent and oxident into said formation via an injection well for a finite period of time and subsequently returning the system to its initial operating mode.

Abstract: In a process for the recovery of resources from underground geological structures, the process is improved by fracturing the walls of the underground structure and large boulders or rocks by inducing thermal gradients in the deposits. Determination of the thermal gradients which will produce the desired fracturing pattern in each specific deposit involves subjecting a core sample to a controlled heating program. When the heating program has been established from tests on the core sample, it is then applied to the underground formation.

Abstract: The present invention relates to an improved method for the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to an improved method which enhances significantly the recovery of the mineral from a subterranean formation via solution mining. The improvement comprises switching a well which initially functions as a producer to an injector and vice versa after oxidant breakthrough has occurred at a production well.

Abstract: A method of in situ solution mining is disclosed in which a primary leaching process employing an array of 5-spot leaching patterns of production and injection wells is converted to a different pattern by converting to injection wells all the production wells in alternate rows.

Abstract: A downhole recirculator for injecting two-phase lixiviant from a tubing string into a leaching interval of an in situ mine field injection hole, and for circulating the injected lixiviant within the leaching interval. The recirculator includes a core device which is adapted to be readily inserted or removed from its operating position in a fixture defining the upper limit of the leaching interval. The core device includes an induction valve arrangement whereby a primary flow of two-phase lixiviant supplied from the minefield surface by way of the tubing string induces a secondary flow of lixiviant from regions of the injection hole near the top of the leaching interval. The primary flow two-phase lixiviant is combined with the secondary flow lixiviant and injected to a region near the bottom of the leaching interval to establish a circulatory motion of lixiviant within the leaching interval.

Abstract: A method of treating a subterranean formation which has undergone an in situ leaching operation which utilized an ammonium carbonate and/or bicarbonate lixiviant. In such a leach operation, ammonium ions will absorb onto the clay in the formation and will present a threat of contamination to any ground waters that may be present in the formation. The present method involves flushing the formation with a strong, basic solution, e.g., sodium or calcium hydroxide, to convert the ammonium ions to ammonia which is easily carried from the formation by the basic solution. After substantially all of the ammonium ions are removed, the formation is then flushed with water to remove any basic solution which may remain in the formation.

Abstract: In a leaching process to recover a selected element or mineral from a gangue, an AC current is applied to the mixture to accelerate the rate at which chemical reactions occur. If the treated material is located in a subsurface earth formation, the AC current may further generate gases in situ to assist in moving and circulating the leaching solution in the formation and to bring the dissolved mineral value to the surface through a borehole or the like. This acceleration of the chemical reactions can shorten the effective leaching time from weeks or months to a matter of hours or days, thereby greatly affecting the rate of recovery of the mineral value and making such leach mining economical on a commercial basis.

Abstract: The present invention relates to a process for the solution mining of uranium from a subterranean formation. More specifically, the invention relates to the injection of an alkaline leach solution undersaturated in carbonates into a subterranean formation for the mining of uranium.

Abstract: A process for the in-situ recovery of hydrocarbon, carbon monoxide, and hydrogen values and associated minerals from subsurface oil shale deposits is provided by forming a gas-tight retort chamber and injecting it with a hot, pressurized gas followed by a solvent extraction and finally a combustion of the hydrocarbon residue. In order to conduct the process, the shale formation must be beneath a gas impermeable geological structure which will form a gas-tight chamber upon leaching of the water soluble minerals.

Abstract: In the in-situ leaching of valuable minerals such as uranium, a leaching solution is injected into the mineral-bearing formation, permitted to remain in contact with the formation to effect the solubilization of desirable mineral values therefrom, and then withdrawn either from the original injection well or a nearby production well. Presently, upon removal from the production well, the mineral bearing solution is filtered aboveground prior to chemical extraction of the valuable minerals. A serious problem has arisen in that highly radioactive radium ions have been found to accumulate, both in the circulating leach solution and in various aboveground equipment resulting in serious waste disposal problems. The instant method utilizes a sand pack containing barium salts, which ion exchange with the radium ions so that the latter are prevented from reaching the surface.

Abstract: A process is disclosed for in-situ mining of copper from a subterranean ore body characterized, at least in part, by the presence of a sulfidic ore and by natural, microscopic fracture openings. The process comprises forcing a stable, two-phase lixiviant comprising an aqueous phase, a multiplicity of gaseous, oxygen-containing bubbles having a size sufficient to pass through the natural fracture openings in the ore body, and a surfactant for enhancing the formation of the bubbles and for minimizing bubble coalescence through the ore body to leach copper.The aqueous and gaseous phases of the lixiviant are mixed at the surface and injected into the leaching interval through an injection hole, or preferably, are mixed in a subterranean sparger within the hole above the leaching interval. The pregnant liquor is recovered through one or more production holes and, after the copper is recovered, the lixiviant may be reconstituted and recirculated.

Abstract: This invention pertains to a method for in-situ mining of copper values from ore formations and, more particularly, this invention pertains to oxidative in-situ mining of copper wherein, for example, an oxygen-acid, a ferric iron-acid or a nitrate-acid lixiviant is being employed for recovering copper values. Further, this invention pertains to the recovery of copper from a deposit in which the ratio of pyrite to chalcopyrite is low. Still further, this invention pertains to a combination of acid-preinjection, monitoring, acid adjustment and additional monitoring or tell-tale ion monitoring for acid supply increase or decrease in the ore formation as steps in a combination for rendering highly controllable the acid preinjection process, thus providing further improvements to in-situ mining processes.

Abstract: This invention is a process for treating an underground formation of coal by contacting the coal with a basic aqueous solution for a time sufficient to disintegrate at least a portion of the coal formation. Subsequently, at least some of the disintegrated material is removed to create permeability in the coal formation. The coal is then treated with a heat carrying fluid to recover energy values from the coal. Another aspect of this invention is a process for slurry mining coal which comprises contacting the coal with the basic aqueous solution for a time sufficient to disintegrate the coal and form a slurry, then conveying said slurry to a receiving terminal.

Abstract: The present invention relates to an improved method for the solution mining of a mineral from a subterranean formation. More specifically, the invention relates to an improved method which enhances significantly the recovery of a mineral from a subterranean formation via solution mining utilizing an injection and production well. The improvement comprises positioning an injection well in the reduced zone and a production well in the oxidized zone of a formation.

Abstract: In producing shale oil from a relatively permeable leached zone within a subterranean oil shale deposit, hot aqueous fluid is flowed between wells along paths which are vertically varied. An initial flow between near-bottom injection and production locations within the leached zone is varied by steps inclusive of producing fluid from a near-top location and injecting fluid into the initial production location.

Abstract: This invention relates to the production of combustible gases from coal in situ, in which one or more passages are established between the surface of the ground and an underground coal deposit. The coal is set afire and the fire is sustained by injection of an oxidizer for a period of time. Oxidizer injection is terminated, followed by injection of steam for a period of time into the hot coal bed. Produced gases are captured at the surface. Products of combustion from the burn cycle are saved at the surface, reconstituted by the addition of oxygen, then reinjected for subsequent burn cycles until the sulfur dioxide content is sufficiently high to warrant recovery in surface facilities. Condensible gases are cooled in surface facilities with liquids captured apart from noncondensible gases.

Abstract: A method for rubblizing an oil shale deposit that has been formed in alternate horizontal layers of rich and lean shale, including the steps of driving a horizontal tunnel along the lower edge of a rich shale layer of the deposit, sublevel caving by fan drilling and blasting of both rich and lean overlying shale layers at the distal end of the tunnel to rubblize the layers, removing a substantial amount of the accessible rubblized rich shale to permit the overlying rubblized lean shale to drop to tunnel floor level to form a column of lean shale, performing additional sublevel caving of rich and lean shale towards the proximate end of the tunnel, removal of a substantial amount of the additionally rubblized rich shale to allow the overlying rubblized lean shale to drop to tunnel floor level to form another column of rubblized lean shale, similarly performing additional steps of sublevel caving and removal of rich rubble to form additional columns of lean shale rubble in the rich shale rubble in the tunnel, an

Abstract: Disclosed is a method of preferentially solution mining potassium chloride from a stratified subterranean deposit of potassium chloride and sodium chloride where a plurality of strata are present in a single common solution mining cavity. According to an embodiment of the disclosed method, a first aqueous working solution is established in a lower zone of the cavity in contact with lower strata. Thereafter, a second aqueous working solution is established in contact with a higher zone intended to be preferentially mined. The second aqueous working solution is maintained at a lower specific gravity than the first aqueous working solution. Effluent is withdrawn from the second aqueous working solution near the lower boundary thereof and an extracting solution is added to the cavity at a rate sufficient to maintain the second aqueous working solution less dense than the subjacent solution, i.e., the first aqueous working solution.

Abstract: Producing a fracture network in deep rock, e.g., in an ore body, by detonating explosive charges sequentially in separate cavities therein, the detonations producing a cluster of overlapping fracture zones and each detonation occurring after liquid has entered the fracture zones produced by previous adjacent detonations. High permeability is maintained in an explosively fractured segment of rock by flushing the fractured rock with liquid, i.e., by sweeping liquid through the fracture zones with high-pressure gas, between sequential detonations therein so as to entrain and remove fines therefrom. Ore bodies prepared by the blast/flush process with the blasting carried out in substantially vertical, optionally chambered, drilled shot holes can be leached in situ via a number of holes previously used as injection holes in the flushing procedure and a number of holes which are preserved upper portions of the shot holes used in the detonation process.

Abstract: A method of separating and removing magnesium chloride hexahydrate from deep subterranean salt formations containing magnesium chloride hexahydrate, such as a carnallite bed or a bischofite bed, wherein one or more holes are drilled or provided through an overburden and into the bed. A solvent formed from any one of the lower saturated monohydric aliphatic alcohols having 1 to 4 carbon atoms, such as methanol, is directed downwardly in the hole and into contact with the bed, then upwardly through and out of the cased hole. Magnesium chloride hexahydrate is dissolved selectively by the solvent, but other salts, such as potassium chloride and sodium chloride, remain substantially insoluble in the solvent. The insolubles may be elevated out of the hole simultaneously with the lifting of the solvent-magnesium chloride hexahydrate solution or subsequent to such lifting.

Abstract: A solvent of coal is pumped through pipes drilled into the earth to a coal seam. The coal is digested or dispersed into the solvent and solvent recycle, and is thereafter pumped as a solution up to the surface and processed to remove the coal from the solvent. The method produces low-ash coal, stripped of all the extraneous ash, leaving the inherent ash, and stripped of all the sulfur except the organic type. The method comprises making a coal solution in situ and bringing it to the earth surface economically, without the hazards and environmental problems of conventional coal mining and without the need of coal washing facilities.

Abstract: A method of extracting metal from an underground ore body. The body is heated by electric induction to a temperature sufficient to break up the metallic ore compound and liquefy the metal. The metal flows into production wells where it is collected and transported to the surface, as by rapid solidification into powder or pellets in a pressurized gas stream. The electric induction is conveniently effected by passing alternating current through a conductor encompassing that portion of the ore body to be heated.

Abstract: Subterranean mineral deposits, such as oil shale or the like, are prepared for in-situ retorting by selectively mining out an area at the base of the deposit leaving an overlying deposit supported in a suitable manner such as by a plurality of pillars. The overlying deposit is expanded in any suitable manner into the underlying area in a fashion to create a predetermined distribution of permeability from an area of low permeability to an area of high permeability. An inlet is provided at the low permeability area and an outlet at the high permeability area. A suitable medium is introduced into the deposit at the low permeability end for extracting and forcing mineral values from the deposit toward the outlet end for recovery.

Abstract: In producing shale oil by circulating hot fluid into and out of void spaces within a subterranean oil shale, a plurality of cavities are formed around a central well, the cavities and the well are interconnected by leaching an areally extensive void space within a layer of water-soluble mineral, and hot fluid is circulated in through the cavities and out through the central well.

Abstract: A process is provided for the recovery of chemicals, such as chlorides, sulfates, carbonates and borates of such alkali metals as sodium and potassium, among others, from underground brines associated with an ore body containing said chemicals, wherein the underground brine is pumped to the surface and confined over said ore body where it is concentrated by solar evaporation and the concentrated brine returned to an underground basin adjacent said ore body and stored for later removal by pumping for the subsequent recovery of chemicals therefrom. Thus, solar evaporation is used to produce the desired concentration of brine to optimize the subsequent recovery of chemicals therefrom, thereby resulting in substantial savings in overall energy costs.

Abstract: The forming of a rubble-containing cavity within a subterranean oil shale is improved by: leaching water-soluble minerals to form an areally extensive void in or above an upper portion and an areally extensive permeable zone or void within or contiguous with a lower portion of the oil shale; displacing an explosive fluid into the lower permeable zone; and detonating the explosive.

Abstract: A method of connecting wells for the purpose of producing salt by solution mining. Two wells are drilled into the salt bed, one of which is drilled in the conventional manner, that is, essentially vertically and the other of which is drilled from a point on the surface a selected distance from the first well and is deflected in the direction towards the conventional well so that the bottom of the deflected well approaches within a selected distance of the bottom of the conventional well. After the two wells are drilled the salt is fractured by the use of a conventional high pressure liquid fracturing technique in one or the other or both of the two wells, so that a fracture for fluid flow between the two wells will hopefully be obtained. Thereafter the salt is mined by flowing fresh water down one well and withdrawing saturated salt solution from the other well, the water passing from one well to the other through the fracture zone where it dissolves the salt, creating a cavity.

Abstract: Methods of and apparatus for separating hydrocarbonaceous substances from mineral solids with which they are mixed, in situ or after they have been removed from the geological formation in which they occur. A solvent extraction technique is employed; and trichlorofluoromethane is used as, or a major constituent of, the extraction solvent.

Abstract: Mineral values are recovered in situ by generating a leaching agent in the formation containing the mineral to be recovered.