Patent Application
20090218876
The present invention relates generally to a method of fluid containment and control for in-situ mining, particularly to a method of uranium mining.
Mining involves recovering a target material, such as a mineral or metal, from an ore-body. The ore-body is contained within a below ground mining zone. Conventional mining involves removing the ore-body from the mining zone, transporting the removed ore-body to an above ground location, and recovering the target material by an above ground process.
In-situ mining involves leaving the ore-body in the ground. The target material is recovered from the mining zone by a fluid that dissolves and/or solubilizes the target material to form a pregnant solution containing the target material. The pregnant solution is pumped to an above ground location where the target material is recovered. It is important that the in-situ fluid mining process minimize co-mingling of the in-situ fluid and/or pregnant solution with water resources adjacent to the in-situ mining wellfield.
These and other needs are addressed by the subject invention. The Inventors have developed a method for substantially isolating and containing an in-situ fluid within a mining zone and isolating the fluid from adjacent groundwater resources.
One aspect of the present invention is a method for mining comprising:
Another aspect of is a mining method, comprising:
Yet another aspect of the present invention is method for mining a uranium-containing mineral, comprising:
The mining zone is positioned below ground between the upper and lower non-mining zones and adjacent to the one or more non-mining zones. In one embodiment, at least one of the one or more non-mining zones contains an aquifer. In one configuration, one or more aquifers are contained within the more or more non-mining zones.
The mining zone contains a target material. The target material can include, without limitation, at least one of a target mineral, a target chemical composition and a target metal. In a preferred embodiment, the target material is selected from the group consisting essentially of uranium, uranium-containing compositions, soda ash, soda ash-containing compositions, pot ash, pot ash-containing compositions, precious metals, precious-metal containing compositions, noble metals, noble-metal-containing compositions, gaseous substances, heavy metals, heavy metal-containing compositions, and combinations thereof. The precious metals comprise, without limitation: platinum, gold, silver, osmium, iridium, ruthenium, rhodium, and palladium. The noble metals comprise, without limitation: copper, nickel, manganese, molybdenum and transition metals of groups 4-11 of the standard periodic table. The heavy metals comprise, without limitation: cadmium, selenium, vanadium, lead, bismuth, thallium, indium and other metals of groups 12-15 of the standard periodic table.
The mining zone, the barrier-forming zone, and the one or more non-mining zones have porosity and permeability. As used herein, effective porosity (referred to hereafter as porosity) is a ratio of the volume of interconnected openings, voids and/or pores in the respective zone to the total volume of the respective zone. As used herein permeability is a measure of the ease with which a fluid flows through the volume openings, voids and/or pores of the respective zone. It can be appreciated that the porosity and permeability of the mining, barrier-forming, and the one or more non-mining zones can differ.
The barrier forming means comprises, without limitation, contacting a barrier-forming substance with a barrier-forming zone to decrease the mobility ratio and/or the permeability in at least some of the barrier-forming zone. The decreased mobility ratio and/or reduced permeability forms the barrier zone by blocking and/or impeding flow through in at least some of the plurality of the volume openings, voids, and/or pores within the barrier zone. The decreased mobility ratio and/or permeability substantially blocks and/or impedes fluid flow within the barrier zone.
In one embodiment, the barrier zone is positioned adjacent to the mining zone. In a preferred embodiment, the barrier zone is at least one of: (a) substantially positioned between the upper and lower non-mining zones and (b) between the one or more non-mining zones and the mining zone. In a preferred embodiment, the barrier zone is substantially positioned between the upper and lower non-mining zones and substantially encircles the mining zone. In a more preferred embodiment, the barrier zone is positioned between the mining zone and the one or more aquifers.
The means for forming a barrier zone further comprises, without limitation, contacting the barrier-forming substance with one of at least a portion of a barrier-forming zone. The barrier-forming zone comprises at least a portion of one or more of: a) the mining zone, b) the one or more to the non-mining zones, and c) combinations thereof. Stated another way, the barrier-forming zone is positioned adjacent to and/or between the mining zone and the one or more non-mining zones. In one configuration, the barrier-forming zone comprises at least some of one or more of the mining zone and/or the one or more non-mining zones.
In one embodiment, at least some of the plurality of volume openings, voids, and/or pores have a pore fluid have a viscosity. In another embodiment, at least some of the plurality of volume openings, voids, and/or pores have the barrier-forming substance therein, the barrier-forming substance has a viscosity.
One embodiment of the present invention is a method of controlling the viscosity within the plurality of volume openings, voids, and/or pores within the barrier zone with the barrier-forming substance. The controlled viscosity within the plurality of volume openings, voids, and/or pores is sufficient to substantially block and/or impede fluid flow into and/or out of at least most of the plurality of volume openings, voids, and/or pores within barrier zone.
In a preferred embodiment, the barrier-forming substance comprises a chilled fluid. The chilled fluid is selected from the group consisting of liquid substances, gaseous substances, and combinations thereof. The chilled fluid comprises a fluid having a temperature less than the barrier-forming zone initial ambient temperature. In one embodiment, the chilled fluid comprises a fluid having a temperature less than the initial ambient temperature of the barrier-forming zone. In an even more preferred embodiment, the chilled fluid comprises one of chilled water, chilled air, and a mixture thereof. Contacting the chilled fluid with the barrier-forming zone decreases the temperature in the barrier-forming zone. Not wanting to be bound by theory, the decreased temperature increases the viscosity within at least most of a plurality of the volume openings, voids, and/or pores within the barrier-forming zone. In another embodiment, the decreased temperature partially and/or completely blocks at least some, if not most, of a plurality of volume opening apertures, void apertures, and/or pore apertures within the barrier-forming zone. The increased viscosity and/or blockage of the volume openings, voids, and/or pores form the barrier zone. The increased viscosity and/or blockage of the plurality of volume openings, voids, and pores within the barrier zone substantially impedes fluid flow between the mining zone and the one or more non-mining zones.
In one embodiment, the chilled fluid is formed by a chilling means. The chilling means comprises, without limitation, any method known within the art for lowering the temperature of the barrier-forming substance. Non-limiting examples of chilling means comprise: refrigerating the barrier-forming substance, subjecting the barrier-forming substance to a heat exchange operation, subjecting the barrier-forming substance to a thermal exchange process, and combinations thereof. The chilling means is conducted at one of ground level, below ground level, and ground and below ground levels.
Mining means comprises, without limitation, methods for extracting the target material from a mining zone. More preferred mining means comprise extracting the target material from the mining zone with an extraction fluid.
In a preferred embodiment, the mining means comprises an in-situ mining process comprising contacting the extraction fluid with the target material and/or a target material-containing composition. The contacting of the extraction fluid with the target material and/or a target material-containing composition is conducted within the mining zone. The contacting of the extraction fluid with the target material and/or target material-containing composition forms a pregnant solution containing the target material dissolved and/or solubilized in the extraction fluid.
The mining zone is at least permeable to the extraction fluid. That is, the extraction fluid is substantially able to flow through the mining zone. Preferably, the mining zone porosity and permeability is at least sufficient that the extraction fluid flows within the mining zone.
In a more preferred embodiment, the in-situ mining means comprises a lixiviant. Within the present invention, lixiviant means a fluid substance and/or a substance contained within a fluid to selectively extract the target material from the mining zone. The lixiviant extracts the target material from the mining zone by a leaching process. In a preferred embodiment, the lixiviant dissolves and/or solubilizes the target material to form a pregnant and/or concentrated solution containing the target material. In a more preferred embodiment, the lixiviant is an aqueous solution. In another preferred embodiment, the target material is recovered from the pregnant solution by further processing.
In a more preferred embodiment, the mining means comprises a lixiviant to extract uranium from the mining zone. The lixiviant comprises one of an acid or an alkaline solution. In one configuration, the lixiviant further comprises a complexing agent and/or an oxidant. Non-limiting examples of the oxidant are hydrogen peroxide, peroxides, and superoxides. More preferred oxidants comprise peroxides and hydrogen peroxide. More preferred acid solutions comprise mineral acid solutions. An even more preferred acid solution comprises sulfuric acid and solutions comprising sulfuric acid. Preferred alkaline solutions comprise sodium bicarbonate, ammonia bicarbonate, and combinations thereof.
In one embodiment, the barrier zone substantially maintains the mining means within the mining zone. In a preferred embodiment, the means for forming the barrier zone is substantially maintained during the means for mining. In a more preferred embodiment, the barrier zone substantially maintains the in-situ mining process within the mining zone during the in-situ mining process. In another preferred embodiment, the barrier zone maintains at least one of the lixiviant and pregnant solution within the mining zone. In yet another preferred embodiment, the barrier zone substantially inhibits fluid exchange between at least one of the one or more aquifers and the mining zone.
In one embodiment, at the conclusion of the mining operation, the barrier zone is removed. The barrier removal means comprises, without limitation, a warming means. The warming means comprises, without limitation, one of: ceasing the injection of the chilled fluid; ceasing the injection of the barrier-forming substance; injecting a second substance; and a combination thereof. In one embodiment, the second substance comprises a fluid having a temperature equal to or greater than the chilled fluid, preferably, at least equal to the ambient temperature of the mining zone. The barrier zone removal means substantially restores the mobility ratio of fluid within and/or the permeability of the barrier-forming zone to conditions similar to those that existed prior to the formation of the barrier zone.
In another embodiment, the barrier-forming substance comprises, without limitation: gelling agents; moisture activated, polymerizable substances; viscosity modifiers; polyelectrolytes; polymeric substances; cooling agents; or combinations thereof.
Another embodiment of the present invention is a method of creating a difference in mobility between one or more in-situ mining fluids and a surrounding fluid barrier zone. In one embodiment, the difference in mobility creates a focused mining zone. In another embodiment, the difference in mobility creates a focused area for mining zone restoration. In yet another embodiment, the difference in mobility minimizes and/or substantially eliminates commingling of the mining means with the groundwater resources adjacent to the mining zone. In still yet another embodiment, groundwater resources adjacent to the mining zone are substantially, if not completely, isolated from the in-situ mining process.
Another aspect of the present invention is a method for limiting environmental impact during and/or after the means for mining. Another aspect is a method for substantially restoring at least most of the original environmental conditions to the barrier zone.
Other embodiments of the present invention include: a decreased use of groundwater resources within the barrier zone; a decreased use of ground resources that otherwise would have been drawn into the mining zone from outside the barrier zone during in-situ mining: a more focused drawdown of the in-situ mining zone; and/or a more complete and through environmental restoration of the mining zone.
These and other advantages will be apparent from the disclosure of the invention contained herein.
As used herein, “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.
In step 109, a barrier zone 106 is formed adjacent to a mining zone 108, the mining zone 108 having a target material. The mining zone 108 is positioned between upper 111 and lower 112 non-mining zones. Adjacent to the mining zone 108 are positioned one or more non-mining zones 107. In one embodiment, the one or more non-mining zones 107 contain one or more aquifers 110.
The barrier zone 106 is form by a barrier forming means. The barrier forming means comprises, without limitation, contacting a barrier-forming substance with a barrier-forming zone 119. In one embodiment, the barrier-forming means comprises, without limitation, the contacting of the barrier-forming substance with the barrier-forming zone 119 by injecting the barrier-forming substance into the barrier-forming zone 119. The barrier-forming substance is injected by a plurality of barrier zone wells 104. Preferably, the barrier zone wells 104 surround well field 102.
The barrier-forming zone 119 comprises at least one of a portion of one or more of: (a) the mining zone 108; (b) the one or more to the non-mining zones 107; and (c) combinations thereof. Stated another way, the barrier-forming zone 119 can comprise at least some of one or more of the mining zone 108 and/or the one or more non-mining zones.
In a preferred embodiment, the barrier-forming zone 119 is substantially positioned between the upper 111 and the lower 112 non-mining zones and adjacent to the mining zone 108. In a more preferred embodiment, the barrier-forming zone 119 is positioned between: (a) the mining zone 108 and the one or more non-mining zones 107 and (b) the upper 111 and the lower 112 non-mining zones.
The barrier-forming zone 119 has porosity and permeability. That is, the barrier-forming 119 zone comprises a plurality of volume openings, voids, and/or pores. The plurality of the volume openings, voids, and/or pores have a permeability. In one embodiment, at least some, if not most, of the plurality of the volume openings, voids, and/or pores contain a pore fluid having a viscosity and a surface tension. In another embodiment, at least some of the plurality of the volume openings, voids, and/or pores have at least some of the barrier-forming substance therein, the barrier-forming substance having a viscosity and surface tension.
The barrier-forming means comprises, but is not limited to, a barrier-forming substance capable of decreasing the permeability of the barrier-forming zone 119. In one embodiment, the barrier-forming substance decreases the permeability within the barrier-forming zone 119 by blocking and/or impeding fluid flow into at least a portion of the plurality the volume openings, voids, and/or pores within the barrier-forming zone 119. In another embodiment, the barrier-forming substance increases the surface tension of the fluid within at least some, if not most, of the plurality of the volume openings, voids, and pores within the barrier forming zone 119. While not wanting to be bound by any theory, the surface tension and/or viscosity is increased within at least some of the plurality of the plurality of the volume openings, voids, and/or pores by one or more of the barrier-forming means comprising, but not limited to: (a) introducing a viscosity modifying chemical substance (such as a polymer or polyelectrolyte) into the barrier-forming zone 119; (b) causing a solid and/or a precipitate to form (such as precipitating agent) within the barrier-forming zone 119; (c) decreasing the temperature within the barrier-forming zone 119; and (d) combinations thereof.
In one embodiment, the barrier-forming means decreases the permeability within the barrier zone 106 to substantially block and/or impede fluid flow within the barrier zone 106. That is, at least one of the viscosity and/or surface tension within at least some of the plurality of volume openings, voids and/or pores within the barrier zone 106 is sufficiently increased to impede fluid flow within the barrier zone 106. In another embodiment, a sufficient number of the plurality of the volume opening apertures, void apertures and/or pore apertures within the barrier zone 106 are sufficiently blocked to impede fluid flow within the barrier zone 106. Stated another way, the barrier zone 106 is substantially formed by the decreased permeability of at least most of the plurality of the volume openings, voids, and/or pores. Stated another way, an effective level of the permeability is decreased to block and/or impede fluid flow within the barrier zone 106.
In a preferred embodiment, the barrier-forming substance comprises a chilled fluid. The chilled fluid is selected from the group consisting of liquids, gases, and mixtures thereof. In a preferred embodiment, the chilled fluid comprises chilled water. Preferably the barrier-forming substance is chilled to a temperature less than the barrier-forming zone 119 initial ambient temperature. The initial ambient temperature of the barrier-forming zone 119 is the temperature of barrier-forming zone 119 prior to the barrier-forming substance contacting the barrier-forming zone 119. The contacting chilled fluid with the barrier-forming zone 119 decreases the temperature of the barrier-forming zone 119. While not wanting to be bound by theory, the decreased barrier-forming zone 119 temperatures increase the viscosity and/or surface tension to the fluid within the plurality of volume openings, voids, and/or pores and/or voids. In one embodiment, the decreased temperature can partially and/or completely block at least some of the plurality of volume opening apertures, void apertures and/or pore apertures within the barrier-forming zone 119. Stated another way, barrier zone 106 is formed by at least one of the increased viscosity, the increased surface tension and/or blocked apertures within the barrier-forming zone 119.
In one embodiment, the chilling means can be provided by lowering the barrier-forming substance temperature prior to the contacting of the barrier-forming substance with the barrier-forming zone 119. The barrier-forming substance temperature is lowered at one of ground level, below ground level, and both above and below ground level. While not wanting to be limited by example, in one embodiment, the barrier-forming substance temperature is lowered at ground level prior to being injected by one or more of the plurality of barrier zone wells 104. In another embodiment, the barrier-forming substance temperature is lowered below ground level after being injected. In yet another embodiment, the barrier-forming substance temperature is first lowered above ground and then further lowered below ground. In yet another embodiment, the thermal energy byproduct of the below ground chilling means is transported to the surface for exhausting. Optionally, the exhausted thermal energy is captured and used in above ground operations. In one optional embodiment, the thermal energy byproduct is used as a barrier zone removal means.
The temperature of the barrier-forming substance can be lowered by any chilling means known within the art. While not wanting to be limited by example, the chilling means comprises, but is not limited to, one or more of lowering the temperature of the barrier-forming substance by one or more of: a refrigeration process; heat exchange operation; a thermal exchange process; a thermal exchange process with a composition of matter having a lower temperature; and a combination thereof.
In one embodiment the barrier-forming substance physical properties inherently comprise the chilling means. For example, a barrier-forming substance having a boiling point below the ambient temperature of barrier-forming zone 119 inherently contains a chilling means due to the physical property of its boiling point. Non-limiting examples of barrier-forming substances having boiling points below ambient temperature of at least most barrier-forming zones 119 are liquefied gases, such as, but not limited to, nitrogen, air, methane, ethane, and helium.
In another embodiment of the present invention, the barrier-forming substance comprises one or more of: gelling agents, moisture activated, polymerizable substances, viscosity modifiers, polyelectrolytes, polymeric substances, cooling agents, and mixtures thereof. It can be appreciate that, the plurality of barrier zone wells 104 are spaced throughout the perimeter of the fluid barrier zone 106. In one aspect, the one or more groundwater aquifers 110 are substantially, if not mostly, isolated from the in-situ mining fluids of the well field 102.
A means for mining is conducted in step 121. The mining means comprises, without limitation, extracting and recovering a target material. Preferably, the mining means comprises, but is not limited to, one of: (a) excavating and transporting at least a portion of mining zone 108 to a ground level location for recovery of the target material and (b) conducting an in-situ mining process to recover the target material.
In a preferred embodiment, the in-situ mining process comprises an extraction fluid for extracting the target material. The extraction fluid is one of a liquid, a gas, or a combination thereof. Preferably, the extraction fluid is a lixiviant. The target material comprises one or more of: target chemical compositions, target metals, target metal alloys, target metal-containing minerals, and combinations thereof. In a preferred embodiment, the target material is selected from the group consisting of uranium, uranium-containing materials, soda ash, soda ash-containing materials, pot ash, pot ash-containing materials, precious metals, precious metal-containing materials, noble metals, noble metal-containing materials, gaseous substances, heavy metals, heavy metal-containing materials, and combinations thereof. The precious metals comprise, without limitation, platinum, gold, silver, osmium, iridium, ruthenium, rhodium, and palladium. The noble metals comprise, without limitation, copper, nickel, manganese, molybdenum and transition metals of groups 4-11 of the standard periodic table. The heavy metals comprise, with limitation, cadmium, selenium, vanadium, lead bismuth, thallium, indium and other metals of groups 12-15 of the standard periodic table.
In a preferred embodiment, the target material is uranium and the lixiviant comprises an acid or alkaline solution. In another embodiment, lixiviant further comprises at least one of a complexing agent and an oxidant. Non-limiting examples of the oxidant are hydrogen peroxide, peroxides, and superoxides. Preferred oxidants comprise peroxides and hydrogen peroxide. In a preferred embodiment the acid solution comprises one of: a mineral acid, a mixture of mineral acids, a solution having one or more mineral acids. A more preferred acid solution comprises sulfuric acid, fluids containing sulfuric acid, and aqueous solutions thereof. In a preferred embodiment the alkaline solution comprises one of sodium bicarbonate, ammonia bicarbonate, and combinations thereof. In a more preferred embodiment, the lixiviant comprises an aqueous solution.
In a preferred embodiment, the in-situ mining process comprises contacting the lixiviant with the target material within the mining zone 108. That is, the mining zone 108 has sufficient permeability for the lixiviant to flow through the mining zone 108.
The contacting of the lixiviant with mining material dissolves and/or solubilizes the target material to form a pregnant and/or concentrated solution containing the target material. In a preferred embodiment, the lixiviant dissolves and/or solubilizes the uranium and/or the uranium-contacting substances to form a uranium-containing pregnant solution. The pregnant solution is removed from the mining zone 108 and transported to ground level by one or more extraction wells 113.
In step 127, the target material is recovered from the pregnant solution by further ground level processing. While not wanting to limited by example, the pregnant solution is further processed to recover at least the target material by one or more of: ion-exchange, precipitation, electro-winning, cementation, membrane separation, and combinations thereof. It can be appreciated that, one or more other materials of commercial value can be recovered during and/or after the further processing to recover the target material form the pregnant solution.
In step 123, the barrier zone 106 is substantially maintained during the in-situ mining process of step 121. The barrier zone 106 is substantially maintained during the in-situ mining process by substantially maintaining the barrier zone forming means during the mining means. In a preferred embodiment, the barrier zone is maintained during the in-situ mining process.
In step 129, the barrier zone 106 is removed by the means for removing the barrier zone. The means for removing the barrier zone can include, without any limitation, restoring the permeability of the barrier zone 106 to a level substantially about equal to the permeability of the barrier zone 106 prior to barrier forming means. That is, the permeability of the barrier zone 106 is substantially returned to about its permeability prior to the formation of the barrier zone. The warming means comprises, without limitation, one of: ceasing the injection of the chilled fluid; ceasing the injection of the barrier-forming substance; contacting a second fluid with the barrier zone; and a combination thereof.
In one embodiment, the second substance comprises a warming fluid having a temperature equal to or greater than the chilled fluid. Preferably, the temperature of substance is at least equal to the ambient temperature of mining zone. The contacting of the warming fluid with the barrier zone substantially returns the permeability of the barrier zone and/or barrier-forming zone to about it permeability prior to the formation of the barrier zone.
While not wanting to be bound by any theory, one or more of the ceasing of the injection of the chilled fluid and the contacting of the warming fluid with the barrier zone substantially returns the barrier zone to substantially about at least its ambient temperature. The returning of the barrier zone to about at least its ambient temperature substantially returns the permeability of the barrier zone and/or the barrier forming zone to about its permeability prior to the formation of the barrier zone.
The ceasing the injection the barrier formation substance and/or the contacting of the second substance with the barrier zone removes the barrier zone by a chemical and/or physical process. The chemical and/or physical process substantially reverses the barrier formation process. While not wanting to be limited by any theory, the cessation of injecting the barrier formation substance and/or contacting of the second substance substantially reverses by a chemical and/or physical process the decreased permeability caused by one or more of: the gelling agent; moisture, activated polymerizable substance; viscosity modifier; polyelectrolyte; and polymeric substance.
Another embodiment is a method substantially limiting the environmental impact on fluid barrier zone 106. One aspect is a method of restoring the fluid barrier zone 106 to at least most of its environmental conditions.
Yet another embodiment of the present invention, is a decrease consumptive use of groundwater resources, compared to in-situ mining operations of the prior art.
Still yet another embodiment is increased drawdown of an in-situ mining well field 102, compared to the in-situ operations of the prior art.
In still yet another embodiment is a more focused drawdown of an in-situ mining filed 102, compared to the mining operations of the prior art.
Another embodiment is a more complete and through restoration the well field area 102.
Another embodiment is the in-situ mining recovery of soda ash and potash.
The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.
The following is a listing of components referenced within the detailed description section of the specification:
100 barrier zone design
101 injection well
102 well field
104 barrier zone well
106 barrier zone
107 non-mining zone
108 mining zone
110 aquifer
111 upper non-mining zone
112 lower non-mining zone
113 extraction well
115 process
119 forming a barrier zone
121 conducting an-situ mining process
123 maintaining the barrier zone
127 recovering target value
129 removing the barrier zone
The present application claims the benefit of U.S. Provisional Application Ser. No. 61/032,824 filed Feb. 29, 2008, which is entitled “Method of Achieving Hydraulic control for In-situ Mining Through Temperature-Controlled Mobility Ratio Alterations” which is incorporated herein by this reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61032824 | Feb 2008 | US |
