Abstract: The present invention relates to a method for restoring to environmentally acceptable levels the soluble contaminants in a subterranean formation that has been subjected to oxidative leaching. The contaminants are defined as those ionic species that when subjected to calcium ions form precipitates which are insoluble in the formation fluids. In accordance with the present invention, soluble calcium values are introduced into the formation. The level of contaminants is monitored and when such reaches the desired level, the introduction of soluble calcium values is stopped. The introduction of calcium values may be achieved in several ways one of which is to inject into the formation an aqueous solution containing therein solubilized calcium values. Another method of introducing calcium values into a formation, is to inject into the formation an aqueous solution containing carbon dioxide to solubilize calcium values, such as calcium carbonates, found in the formation.

Abstract: Solution mining method particularly adapted for recovery of potash and the like from multiple beds of relatively thin, inclined strata at substantial depths. Dissolution of each ore strata overlain by an insoluble and impermeable strata takes place through a single borehole in sequential order beginning with the deepest ore strata. Water is injected down a borehole at a predetermined rate and, being much less dense than present brine, flows in an updip direction along the top of the cavity to the forward mining face remote from the drill hole. Loaded, heavy brine flows downdip along the bottom of the cavity to an outflow pipe communicating with the bottom of the cavity.

Abstract: A method, and apparatus to practice the method, to complete multiple (triple) branch wells using separate drill and casing templates. Principally this invention finds its greatest utility in the in situ leach mining of deep lying ore bodies. Initially, a generally vertical main hole is drilled in the earth and cased. The particular casing used has an internal indexing dog and specific areas which act as windows from which some of the branch wells are to be drilled. To form the individual branch wells, each window is sequentially drilled out by a drilling assembly which is oriented by a movable drilling template. The template is fixed with respect to the casing for each branch drilling by engaging the indexing dog. After each window and branch well is drilled, the drilling assembly and drilling template are retrieved to the surface and repositioned with respect to each other to provide for the next branch drilling.

Abstract: A process is described for minimizing accumulation of undesirable polythionates on an ion exchange resin used to recover uranium values from a leachate from an in situ mining operation by adding sulfite, either as a sulfite salt or as SO.sub.2, directly to the leachate or to the eluant.

Abstract: A direct precipitation method based on the insolubility of uranyl phosphate in carbonate containing solutions at pH 6-6.5 and its insolubility at pH 8 is described. The method eliminates the use of ion exchange columns for removing uranium values from uranium leachates and can be readily applied to an integrated field operation.

Abstract: A method and the necessary equipment to form horizontal cased and perforated drainholes for an underground, in situ leach mining operation. After a vertical hole has been formed and cased in the earth, horizontal drainholes are to be drilled from below its casing. The depth and thickness of the ore body which is to be recovered is determined. Following this, the proper whipstock orientation is computed and the horizontal drainhole is whipstocked and drilled from above the ore bed into it. A flexible casing, such as Coflexip pipe, is used to case the drainholes. Perforations or slots are provided for in these casings before they are put in the earth. A special retrievable cement plug, basket, and one-way valve are used to control and direct the flow of cement to the volume between the outside of the juncture at the casings.

Abstract: A method for recovering alkali values from subterranean deposits of trona ore associated with sodium chloride by contacting the trona with an aqueous mining solution containing sodium hydroxide and subsequently utilizing the alkali values contained in the resultant salt- and sodium carbonate-containing solution. The alkali values are preferably crystallized as substantially salt-free sodium carbonate monohydrate, which is dried to recover soda ash. The mother liquor containing all of the salt is then treated to prepare a dilute sodium hydroxide solution, which may be employed as aqueous mining solution in a cyclic method to recover additional alkali values from trona.

Abstract: This invention is a comminution process for treating coal with a drying gas to form fractures which weaken the structure of the coal and make it easier to disintegrate mechanically, chemically or by fluid force. Another aspect of this invention is a process for treating an underground formation of coal with a dry gas for a time sufficient to form cracks and fractures in a portion of the formation in order to increase the permeability of the coal formation to the flow of fluids therethrough. Processes for in-situ combustion of the coal formation are therefore more efficient since the coal formation is more permeable to the flow of gas therethrough.

Abstract: A multiple branch well for use with in situ leach mining of deep lying ore bodies. The branch wells may be formed by a method disclosed in a related invention. Each well may have two branches one of which is a producer well and one an injector well. Internally of the main casing from which the two branch casings extend are--from the lower end up--a packer unit, a tubing hanger, and a wireline retrievable hydraulically generated pump. The packer and tubing hanger serve their conventional function of, respectively, blocking the flow of leach fluids and holding the branch tubular casing in place within the main casing. The hydraulic pump joins the tubular casings to maintain a constant ratio of produced fluid to injected fluid. This pump is operated by a pressurized fluid source. Since it is retrievable and hydraulically operated, the pump can be brought to the surface for any repairs or maintenance and it requires less surface plumbing with no down hole electrical power.

Abstract: A permeable region adjacent a well bore used in an acidic in situ leaching system can be repaired by introducing a non-acidic liquid for displacing acidic leach liquid from the permeable region, introducing into the well bore a basic composition including a polymeric material that gels under acidic conditions, and applying sufficient pressure to the well bore to displace at least a portion of the basic composition and polymeric material from the well bore into the permeable region adjacent the well bore. Liquid flow in the well bore is then discontinued for a sufficient time for acid remaining in the subterranean formation adjacent the well bore to contact such polymeric material and cause gelation of the polymeric material in the permeable region. The introduction of acidic leach liquid can then continue.

Abstract: There is provided a process for recovery of metal values from an ore body containing sulfide minerals. The ore body is fractured for increasing its permeability. The fractured ore body is then roasted in situ to increase the permeability and porosity of ore body to liquid leach solutions. The roasted sulfide minerals in the ore body are thereafter contacted with a leach solution to extract metal values therefrom and the extracted metal values are recovered.

Abstract: A method is disclosed for restoring to environmentally acceptable levels the soluble molybdenum values in a subterranean formation which has been subjected to in situ oxidative leaching by passing through the leached formation an aqueous restoration fluid containing ferrous ion.

Abstract: A method is disclosed for restoring to environmentally acceptable levels the ammonia content in a subterranean formation which has been previously subjected to in situ oxidative leaching employing an ammonium leach solution by flushing the formation with carbonic acid.

Abstract: Underground coal is mined by sinking a hole into the coal, passing a coal solvent to the coal, and recovering a coal solution and/or dispersion products from the resulting solution or suspension.

Abstract: Method and apparatus for introducing finely divided gas bubbles into a lixiviant used for in-situ mining of minerals containing metal values, such as copper values. The lixiviant is supplied to a plurality of porous tubes formed of sintered powdered metal while a gas is supplied under pressure about the tubes to cause the gas to penetrate into the interior of the tubes in the form of fine bubbles which are wiped from the interior of the tubes by the lixiviant passing therethrough.The method and apparatus can be advantageously employed in situations where it is desirable to perform in-situ mining with an oxidizing lixiviant. In these cases oxygen is supplied under pressure about the tubes.

Abstract: Method and apparatus for mixing a gaseous oxidant (e.g., oxygen) and a lixiviant (e.g., an aqueous carbonate solution) at a downhole location in a well before the oxygen-saturated lixiviant is injected into a formation to be leached. The invention involves establishing a mixing zone in the well by positioning an orifice plate in the well at the downhole location. Lixiviant as it is flowed down the well passes through a restrictive opening in the plate causing a substantial increase in the flow velocity of the lixiviant. At the same time, gaseous oxidant is supplied to a point adjacent the opening in the plate and due to the increased velocity of the lixiviant flowing through the orifice, the oxidant is trapped to form a gas pocket below the orifice. Lixiviant flows through the gas pocket and becomes saturated with the gaseous oxidant.

Abstract: The present invention relates to in-situ leaching of uranium, particularly employing an acidic leach liquor containing an oxidant, and especially in respect of ores containing significant amounts of transition metals that act as catalysts for peroxidant decomposition. When hydrogen peroxide is used as oxidant under such conditions it decomposes leading to the formation of gas bubbles and exacerbation of ore-blinding, and a reduction in the efficiency of extraction of uranium.The present invention employs peroxymonosulphuric acid as oxidant and thereby ameliorates the problems aforesaid. Preferably, additionally, sulphuric acid is present in the leach liquor and in many preferred embodiments the peroxymonosulphuric acid concentration is from 0.001 to 0.03 moles/liter and the sulphuric acid from 0.025 to 0.075 moles/liter.

Abstract: A packer assembly and its method of use are provided, the packer assembly being carried on a first conduit for use in wells exposed to corrosive injection fluids, the well being encased by a second conduit having a locking recess defined therein, such as by having first and second conduit members, the conduit members being interengaged by coupling whereby the locking recess is defined by the coupling element and between the conduit members. The assembly comprises a body member communicating to the first conduit and having a slotted configuration thereon. An inwardly flexible, outwardly urged collet assembly is exterior of the body, with control means on the collet assembly being carryable within the slotted configuration. Means on said body define a pocket for selective receipt of the collet assembly for locking the collet assembly relative to the locking recess.

Abstract: Methods for increasing the permeability of a subterranean igneous rock formation penetrated by at least one well where a hydraulic fluid is injected into the formation at a pressure sufficient to cause diffusion into the natural fractures thereof and thus increase the cross-sectional area thereof, maintaining the pressure and injecting a second fluid which results, by the use thereof, in substantially maintaining the increased cross-sectional area after the pressure is reduced.

Abstract: A process for the in-situ mining of subterranean uranium ore deposits comprising pretreating the deposits by the steps of injecting an aqueous inorganic chloride solution therein to substantially saturate the deposits and injecting an aqueous alkaline lixiviant solution therein to flush the chloride solution from the deposits. Thereafter, the pretreated deposits may be solution mined in conventional fashion such as by injecting an oxidant-containing aqueous alkaline lixiviant therein and recovering uranium-containing lixiviant solution. The inorganic chloride solution is preferably potassium chloride and the preferred lixiviants are potassium carbonate, sodium carbonate and ammonium carbonate.

Abstract: Process for the in-situ leaching of uranium from a subterranean ore deposit comprising introducing into the deposit an aqueous lixiviant formulated from a dilute sulfuric acid solution which also contains carbon dioxide. The lixiviant has a pH within the range of 1.0-2.5. The lixiviant may also contain an alkali metal sulfate such as sodium sulfate. The process is particularly applicable to subterranean deposits containing uranium associated with carbonaceous material.

Abstract: Method and apparatus for mixing a gaseous oxidant (e.g., oxygen) and a lixiviant (e.g., an aqueous carbonate solution) at a downhole location before the oxygen-saturated lixiviant is injected into a formation to be leached. The invention involves establishing a mixing zone in the well by positioning a mixing means, comprising a housing, in the well at the downhole location. Lixiviant is flowed down the well and through a restrictive opening in the housing to substantially increase the flow velocity of the lixiviant. At the same time, gaseous oxidant is fed to the housing and is trapped therein by the increased velocity of the lixiviant and by packing material in said housing. The lixiviant flows through the trapped oxidant which, in turn, dissolves into the lixiviant to saturate same. Additional packing material is provided in the housing to remove undissolved oxidant from the saturated lixiviant before it is injected into a formation to be leached.

Abstract: Process for the in-situ leaching of uranium from a subterranean ore deposit employing a lixiviant containing an oxidizing agent, sulfuric acid, and carbon dioxide. Prior to the injection of the lixiviant, an aqueous solution of sulfuric acid and oxidizing agent is injected into the deposit in an amount of at least 1 pore volume. The initially injected acid solution is substantially free of carbon dioxide. The process is particularly applicable to subterranean deposits containing uranium associated with carbonaceous material.

Abstract: The instant disclosure relates to a method of tracing the flow of a solution for extracting values from an ore, wherein such extraction leaves behind an extracted ore, which method comprises(a) providing a material in said solution which will interact with said extracted ore to form a product, and(b) detecting said product.The instant invention is especially useful for the extraction of copper values from copper oxide ores such as chrysocolla, neotocite, malacite and cuprite. Preferably, the extraction solution is an acidic solution comprising sulfuric acid and said material is a fluorescent surface-active dye which forms an adsorption product with the porous gel-like aluminosilicate network which remains after extracting the copper values from the above ores. A sample of said extracted ore is obtained by drilling and such sample is irradiated with ultra-violet light, e.g. at a wavelength of from about 220 to about 400 nm, depending on the particular dye to detect such adsorption product.

Abstract: A well for the solution mining of salt from an underground salt formation, comprising a borehole (12) extending from the earth's surface downwards into the formation, a casing (10) that is cemented in said borehole down to the upper level of said formation and separate conduct means provided within said casing and extending through the borehole downwardly beyond said casing, respectively for introducing leaching water into the salt formation and for withdrawing pregnant leach liquor from said formation, which conduct means have adjustable effective lengths, said conduct means each comprising a tubing string (13, 14), the two strings extending parallel through said casing and at least one of said strings carrying a tailpipe (18, 19) of smaller diameter, which tailpipe is axially telescopic in said string, can extend downwardly beyond said string and carries a liner assembly (20, 21, 22, 23) at its upper part that can engage the inner wall of said string at any desired location above the bottom end of the strin

Abstract: Process for treating a well penetrating a subterranean formation which is productive of sour gas in order to alleviate sulfur deposition. An alkyl naphthalene base sulfur solvent is circulated into the well and recovered from the well in admixture with the produced gas. The injected solvent comprises an alkyl naphthalene mixture containing C.sub.1 -C.sub.4 alkyl naphthalenes in an amount within the range of 70-90 weight percent and higher-boiling naphthalenes in an amount within the range of 5-15 weight percent. The sulfur solvent contains no more than a 10 weight percent of naphthalene and has an initial boiling point of at least 230.degree. C., a flash point greater than 101.degree. C., and a freezing point of less than 0.degree. C. The solvent mixture may be dissolved in a carrier oil for introduction into the well.

Abstract: In the solution mining of uranium ores using an aqueous ammonium carbonate leaching solution containing hydrogen peroxide and/or molecular oxygen as oxidant, permeability of the ore formation during the leaching operation is maintained or improved by including a small amount of alkali metal silicate dissolved in the leaching solution. The silicate also improves the stability of the oxidant in many instances.

Abstract: Disclosed is a hollow, elongated heap leaching device for use in above-ground leaching of metal bearing ores. The device has an annular cross-section, an inlet opening near its upper end, a restriction or closure at or near its lower end and narrow slits in its walls above the restriction or closure. The cross-sectional area at its lower end must be sufficiently large to allow it to unsupportedly rest vertically on a leach pad or layer of ore while ore is piled against it.

Abstract: A method for concentrating and recovering uranium material from a solution containing uranium, comprises passing the solution through at least one semipermeable membrane system capable of concentrating uranium, to provide a uranium rich product.

Abstract: Process for the in-situ leaching of uranium employing an alkaline lixiviant and an alkali metal or alkaline earth metal hypochlorite as an oxidizing agent. The use of the hypochlorite oxidant results in significantly higher uranium recoveries and leaching rates than those attained by the use of conventional oxidants. The invention is particularly suitable for use in subterranean deposits in which the uranium mineral is associated with carbonaceous material which retards access to the uranium by the lixiviant.

Abstract: A method for controlling calcium, e.g. calcite, build-up in the leach solution of a uranium and/or related values recovery operation wherein the leach solution is flowed through a value bearing ore to dissolve the desired values. A soluble fluoride, e.g. sodium fluoride, is added to the leach solution after it has passed through the ore to thereby precipitate calcium fluoride from the leach solution and lower the calcium content of the leach solution. The soluble fluoride may be added to the leach solution before the leach solution passes through the process equipment which is used to remove the values from the leach solution or the soluble fluoride may be added after the leach solution passes through the process equipment. If added before, it is preferable to also add a carbonate/bicarbonate solution along with the soluble fluoride to prevent coprecipitation of uranyl/desired value fluoride or to redissolve coprecipitated fluoride back into the leach solution.

Abstract: A process is provided for restoring an ore deposit after uranium solution mining using ammonium carbonate leaching solutions has ceased. The process involves flushing the deposit with an aqueous solution of a potassium salt during which potassium ions exchange with ammonium ions remaining in the deposit. The ammonium-containing flushing solution is withdrawn from the deposit for disposal.

Abstract: In a process for the solution mining of a uranium ore formation using an aqueous alkaline carbonate leaching solution containing hydrogen peroxide as oxidant, the solution is passed through the ore formation in the presence of an alkylidene-1,1-diphosphonic acid. Such an acid has been found to be unique in its capability for stabilizing the peroxide against decomposition in the presence of the uranium ore.

Abstract: Salts from a salt deposit including magnesium and potassium salts are mined by a solution process in a cavity at the lower end of a borehole. A solvent liquid (water) is injected into the cavity at a level that is periodically raised whereby super imposed slices or cuts of the part of the deposit around the borehole are consecutively dissolved. Brine is recovered from a low level in the cavity. The injection rate of the solvent liquid and the recovery rate of the brine are controlled such that the vertical distribution of the potassium content of the brine in the cavity shows a maximum within the uppermost slice or cut.

Abstract: An improved method of restoring a subterranean clay-containing formation having ammonium ions absorbed on the clay, wherein the formation is flushed with a halogenated restoration fluid having a halogen therein which reacts with the ammonium ion in the formation to decompose the ammonium ions is disclosed. The barren ammonia-containing restoration fluid, after it passes through the formation, is withdrawn, reconstituted and recycled as fresh restoration fluid back into the formation. The barren fluid is treated with an appropriate base to raise the pH to a highly alkaline level, the treated highly alkaline barren fluid is passed through an airstripping tower to strip substantially all the ammonia from the fluid, chlorine gas is added to the fluid from which the ammonia has been stripped, while controlling the amount of chlorine to produce a reconstituted restoration fluid of a predetermined pH level. Finally, the reconstituted restoration fluid is recycled back into the formation.

Abstract: A relatively nonvolatile, high molecular weight sulfur solvent produced by activating a dialkyl disulfide oil by the addition of a relatively high molecular weight predominantly aliphatic amine (e.g., a N-alkyl-1,3-propane diamine) and optionally further increasing the molecular weight by the addition of elemental sulfur. Such a sulfur solvent is particularly useful in sustaining a liquid phase at bottomhole conditions for high temperature, high pressure sour gas.

Abstract: A method for enhancing recovery of sodium carbonate from sodium carbonate solutions which contain sodium chloride. Anhydrous sodium carbonate is recovered in good yields from aqueous sodium carbonate solutions containing sodium chloride by evaporative crystallization at superatmospheric pressure and at a temperature of at least about 120.degree. C.

Abstract: Alkali values are recovered in a cyclic method from mechanically mined trona ore or from trona deposits by a solution mining technique utilizing a solvent comprising an aqueous solution of sodium sulfide. The ore is solubilized as sodium carbonate which is precipitated as sodium sesquicarbonate and/or sodium bicarbonate by treating the solution with hydrogen sulfide and the precipitated salt separated from the mother liquor. In the process, sodium sulfide and hydrogen sulfide become converted into sodium hydrosulfide which is contained in the mother liquor. Heat treatment of the mother liquor converts the sodium hydrosulfide into sodium sulfide thereby regenerating a solution of sodium sulfide which is recycled to the trona ore and into hydrogen sulfide which is evolved and recycled to the sodium carbonate solution.

Abstract: Disclosed is a method of solution mining the mineral content of a subterranean cavity containing a rubble pile positioned on the floor thereof and the subterranean cavity communicating with the surface by at least two boreholes, by drilling a liner through a cased borehole into the rubble pile, disconnecting the drill string from the liner, withdrawing the drill string from the borehole, introducing into the borehole a sealing meant to seal the annular space between the liner and the casing, introducing a solvent into the cavity and withdrawing from the cavity a solution enriched in the mineral contained in the rubble.

Abstract: A method for recovering alkali value from sodium bicarbonate-containing ore by utilizing an aqueous solvent containing ammonia. The aqueous ammonia solvent is contacted with the ore to solubilize the sodium bicarbonate-containing ore. The alkali values in the resulting solution are crystallized, preferably as sodium carbonate monohydrate or as sodium sesquicarbonate, which may be processed to recover soda ash. Aqueous ammonia solvent is preferably regenerated from the mother liquor remaining after recovery of the solids, the ammonia solvent then being employed in a cyclic method to recover additional alkali values from the ore.

Abstract: A pretreatment for use in fracturing coal seams to increase gas permeability of the seams. The pretreatment involves injecting a material capable of swelling coal into a coal seam prior to fracturing the coal seam. The pretreatment material swells the coal and closes the natural cleats therein, enhancing the effectiveness of the subsequent fracturing step.

Abstract: An improved leaching method for metal bearing ores, wherein removable, void-forming members are placed near the bottom of the ore body and removed during the leaching process, causing partial internal collapse and shifting of the ore, thus exposing additional ore surfaces to the effect of the leaching solution.

Abstract: Process for the stabilization of formation clays by the use of aluminum in the in-situ leaching of uranium or the restoration of contaminated formations. The aluminum is added to a lixiviant having a pH in the range of 6-10 or to a restoration fluid having a pH of at least 6 in an amount effective for the stabilization of clays.

Abstract: The injection of an ammonium sulfite or bisulfite solution increases the permeability of an uranium ore bed that has suffered permeability losses during the in-situ mining of uranium with an alkaline leach solution containing a peroxide or dissolved oxygen oxidant. Such an injection recovers much of the lost formation permeability, thus decreasing costs and effort required to put needed restoration solutions or further leach solutions through the ore bed. In addition, uranium contamination of the ground water normally occurring after cessation of leaching is significantly lowered by such injection.

Abstract: Magnesium values are leached from a fragmented mass containing combusted oil shale particles. Magnesium is leached selectively with respect to calcium compounds and silicates with aqueous solutions of a mixture of purgeable, acid-forming gases such as carbon dioxide with a minor proportion of sulfur dioxide. A two-stage leaching process can employ leachant with dissolved carbon dioxide and sulfur dioxide in a first stage and with a carbon dioxide containing solution in the substantial absence of sulfur dioxide in the second stage. An enriched solution containing magnesium values is withdrawn from the fragmented mass and magnesia is recovered from such enriched solution. In one embodiment a fragmented permeable mass of formation particles containing oil shale and carbonates of calcium and magnesium is formed in an in situ oil shale retort.

Abstract: The present invention relates to a method for the renovation of an aquifer subsequent to the solution mining of a mineral from the aquifer. More specifically, the invention relates to the utilization of spent ion exchange resin to remove chloride ions from the aquifer.

Abstract: Process for the in-situ leaching of uranium from a subterranean ore deposit employing a lixiviant containing a carbonate leaching agent and an oxidizing agent. The lixiviant is heated to a temperature of at least 110.degree. F. prior to injection into the subterranean ore deposit. The use of a heated lixiviant provides for a substantially greater ultimate uranium recovery than that attained through the use of a lixiviant injected at ambient temperature conditions. The process may be carried out in several stages. In the first stage, a relatively low temperature lixiviant is injected. This is followed by a second stage in which the lixiviant is heated to an elevated temperature and then injected into the deposit. The invention is particularly applicable for use in subterranean deposits which contain uranium associated with carbonaceous material.

Abstract: Subterranean coal seams are treated with ammonia to enhance methane removal and improve the mineability of coal. Residual ammonia remaining from the coal treatment is removed by contacting the coal seam with nitrifying bacteria after ammonia treatment and before mining is carried out.

Abstract: A salt cavern is leached with fresh water by cementing its surface casing in a hole to the depth of the roof of the cavern to be leached, and inserting coaxial short and long leach strings into the hole, with a petroleum liquid between the surface casing and the outer leach string to protect the roof salt from dissolution when fresh water is run down one of the leach strings and the produced brine out the other. To check the progress of cavern formation, the leach strings are removed to permit unimpeded sonar survey; but before this can be done, the pressures within the surface casing and the short and long leach strings must be neutralized, because the petroleum liquid and fresh water and brine all have different specific gravities and so exert different hydrostatic heads. Moreover, as salt dissolution continues during pressure equalization, the specific gravity of the brine changes, so that pressure equalization can take several days.

Abstract: A relatively nonvolatile, high molecular weight sulfur solvent produced by adding at least 40 parts by weight of elemental sulfur per 100 parts by weight dialkyl disulfide to an amine activated dialkyl disulfide oil. Such a sulfur solvent is particularly useful in sustaining a liquid phase at bottomhole conditions for high temperature, high pressure wells.