CA1178195A - Apparatus and method of hydraulically mining unconsolidated mineral formations - Google Patents
Apparatus and method of hydraulically mining unconsolidated mineral formationsInfo
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- CA1178195A CA1178195A CA000398020A CA398020A CA1178195A CA 1178195 A CA1178195 A CA 1178195A CA 000398020 A CA000398020 A CA 000398020A CA 398020 A CA398020 A CA 398020A CA 1178195 A CA1178195 A CA 1178195A
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Abstract
IMPROVED APPARATUS AND METHOD OF
HYDRAULICALLY MINING UNCONSOLIDATED MINERAL FORMATIONS
ABSTRACT OF THE INVENTION
An improved apparatus and method of hydraulically mining unconsolidated mineral formations, such as tar sands is disclosed wherein a portion of the formation adjacent the overburden/mineral bed interface is injected with a bonding agent to form a generally disc-shaped stabilized region which supports the overburden and prevents the same from migrating downward into the mineral bed during the mining process. A non-rotating protective sleeve telescop-ingly positioned along the length of the mining tool and drill string is additionally utilized to reduce drag forces generated in the mineral bed and prevent excessive tor-tional forces being exerted upon the mining tool during the mining process.
HYDRAULICALLY MINING UNCONSOLIDATED MINERAL FORMATIONS
ABSTRACT OF THE INVENTION
An improved apparatus and method of hydraulically mining unconsolidated mineral formations, such as tar sands is disclosed wherein a portion of the formation adjacent the overburden/mineral bed interface is injected with a bonding agent to form a generally disc-shaped stabilized region which supports the overburden and prevents the same from migrating downward into the mineral bed during the mining process. A non-rotating protective sleeve telescop-ingly positioned along the length of the mining tool and drill string is additionally utilized to reduce drag forces generated in the mineral bed and prevent excessive tor-tional forces being exerted upon the mining tool during the mining process.
Description
78~
BACKGROUND OF THE PRESENT IN~ENTION
The present invention relates generally to hydraulic mining tool apparatus and more particularly to an improved hydraulic mining tool and method of hydraulically mining unconsolidated mineral formations such as tar sands.
Recent technology has been developed which permits the recovery of subterranean mineral deposits by use of hydrau-lic mining techniques. Basically, such hydraulic mining techniques are characterized by the use of a high velocity liquid stream which is discharged directly into the sub-terranean mineral deposit to dislodge minerals from their surrounding mineral bed. The freed minerals form a resul-tant slurry with the discharged liquid stream which may be pumped by various means, upward to ground surface and sub-sequently processed by surface separation systems. As the slurry is removed from the formation, a mining cavity or void is formed in the mineral bed which dependent upon the size and type of the particular formation, may extend to 100 feet in diameter throughout the height of the mineral bed. Examples of such hydraulic mining tools are disclosed in U.S. Patent 3,951,457 issued to Redford, U.S. Patent No. 3,439,953 issued to Pfefferle, and my Canadian Patent 1,130,020 entitled Downhole PumP with Bottom Receptor.
As to date, such hydraulic mining techniques have been primarily utilized to recover minerals such as uranium, coal, or potash which typically possess sufficient consoli-dation in their natural formation state so that as the mining cavity or void is formed in the subterranean forma-tion, the surrounding mineral bed remains in its stabilized consolidated condition, thereby defining a "clean" mining cavity. Thus, in such consolidated formations, the over-burden is continuously supported by the consolidated mineral bed and the hydraulic mining tool may be freely rotated and vertically reciprocated within the borehole and mining cavity throughout the mining process. However, in the hydraulic mining of unconsolidated mineral formations such as tar sands,unique mining problems exist which to a great ~ ?
extent has rendered the existing hydraulic mining tool technology commercially infeasible.
In contrast to the above mentioned consolidated mineral formations, unconsolidated formations such as tar sands, typically are non-uniform in composition and often fail to possess the necessary degree of stabilization to maintain a "clean" mining cavity during the hydraulic mining opera-tion. This failure of the ~mconsolidated formations and in particular tar sand formations, is due to the individual sand grains of the formation being stabilized primarily by the compressive forces generated by the weight of the over-burden, with the cementation forces existing between individual sand grains being extremely small in magnitude.
As the subjacent portions of the tar sand mineral bed are removed during the hydraulic mining process, the overburden compressive force balance within the mineral formation is disturbed which, due to only minimal cementation forces existing between the individual sand grain, often results in a "cave-in" or "compaction situation" whereby the sur-rounding mineral bed catastrophically falls in and aroundthe drill string and into the mining cavlty.
When hydraulically mining in relatively shallow unconsolidated formations, the occurrence of such a com-paction situation within the mineral bed often permits the overburden to migrate downward into the borehole and mining cavity, wherein it mixes with the mined mineral slurry and is subsequently transported upward to ground surface during the mining process. As will be recognized, the mining of the non-mineral bearing overburden reduces the overall efficiency of the mining process and if substantial, renders the cost effectiveness of the hydraulic mining process commercially infeasible. Further, in those instances where the downward migration of the overburden is acute, a ~eneral subsidance of the overburden may be experienced whereby the overburden fails to support the necessary surface mining equipment.
Alternatively when mining in deep unconsolidated mineral formations (i.e., greater than 500 feet below ground surface), individual sand grains located proximal the borehole often 3 17B1~5 dislodged from the mineral bed by frictional drag forces exerted by the rotating mining tool and drill string.
Through prolonged duration, these frictional drag forces often disturb the fragile cementation forces existing between sand grains and result in the entire surrounding mineral bed falling in and compacting around the mining tool. Due to the depth in which the mining operation is occuring, substantial pressure is applied along the entire length of the drill string which generates substantial torque on the mining tool during rotation. Such high tortional forces have heretofore required the intermittent shut down of the drilling operation or,in extreme instances, have caused a complete structural failure or twist off of the mining tool within the formation. Such intermittent discontinuance of the mining operation significantly de-creases overall operating efficiency while a twist-off condition typically results in the mining tool being irretrievably lost within the mineral formation.
Thus, there exists a substantial need in the art for an improved hydraulic mining methodand apparatus specific-ally adapted for use in unconsolidated mineral formations which prevents downward migration oE the overburden, reduces frictional drag forces exerted on the mineral bed, and prevents extremely high tortional forces being generated on the mining tool during the hydraulic mining operation.
SUMMARY OF THE PRESENT INVENTION
The present invention comprises an improved apparatus and method of hydraulically mining which specifically addresses and alleviates the above referenced deficiencies associated in the hydraulic mining of unconsolidated mineral formations. More particularly, the present inven-tion comprises the formation of a consolidated, stabilized region or zone adjacent the overburden/mineral bed inter-face which extends radially outward into the formation in a generally disc-shaped configuration. In the preEerred ~17~195 embodiment, this stabilized zone is formed by injecting a suitable liquid bonding agent radially outward in the formation which after a sufficient curing period, bonds the individual overburden particles together to yield a consolidated, stabilized region. By such a procedure, the stabilized region forms in effect a rigid platform which artificially increases the cementation forces existing between the individual formation particles thereby increas-ing the support of the overburden and preventing the down-ward migration of the same during the mining operation.
In addition, the present invention contemplates theuse of a non-rotating protective sleeve which is telescop-ingly positioned along the length of the drill-string extending from ground surface to a location adjacent the mining tool. By use of the non-rotating protective sleeve, the mineral bed in the area adjacent the length of the borehole is substantially isolated from rictional drag forces caused by the rotation of the drill string and, hence, the cementitious forces existing between the individual sand ~0 grains o the ~ormations are not disturbed. As such, the possibility of a "faLl-in" or "cornpaction situation" within the formation is substantially reduced.
In addition to the reduced drag-force benefits made possible by its use, the protective sleeve forms a protective shroud surrounding the length of the drill-string which upon confronting a fall-in condition, shields the major length of the drill-string from direct interaction with the compressive forces exerted by the mineral formation.
Hence, even upon encountering a fall in condition during the mining of deep mineral formations the tortional forces exerted upon the mining tool are maintained at a minimum value. In addition, the protective sleeve permits the rapid withdrawal of the mining tool from the formation and if necessary may be sacrificed and left within the formation while recovering the mining tool and drill-string.
Further, the present invention discloses a novel method of hydraulically mining an entire mineral bearing area or oil field wherein multiple boreholes are formed in ~ ~ 7~ 9 S
the formation at laterally spaced intervals with the spent tailings from the currently mined borehole being returned into the previously mined borehole cavity. As such, environmental pollution considerations are reduced and the surface configuration and habitation of the entire oil field drilling site is maintained substantially in it's natural state.
DESCRIPTION OF DRAWINGS
These as well as other features of the present inven-tions will become more apparent upon reference to the drawings wherein;
~5 Figure 1 is a cross-sectional view taken through a mineral formation depicting the overburden and mineral bed and illustrating the initial step of drilling a borehole from ground surface to a depth adjacent the interface between the overburden and mineral bed;
Figure 2 is an enlarged cross sectional view taken about the in~erface between the overburden and mineral bed oE Figure 1 and depicting the manner in which the stabi-lized consolidated region is formed in the formation;
Figure 3 is a cross-sectional view of the mineral formation depicting the subsequent step of extending the borehole downward into the mineral bed and the insertion of the protective sleeve within the borehole;
Figure 4 isan enlarged cross-sectional view of the mineral bed depicting the relative orientation of the mining tool and drill string with the protective sleeve;
Figure 5A is a schematic representation depicting the position of the hydraulic mining tool and protective sleeve at the initiation of the actual hydraulic mining process;
Figure 5B is a schematic representation of the mineral bed depicting the initial formation of the mining cavity cavity within the formation;
Figure 5C is a schematic representation of the mineral bed depicting the configuration of the mining cavity after a prolonged mining operation;
B1~5 Figure 5D is a schematic representation of the mineral bed illustrating the manner in which the mining tool and protective sleeve may be reciprocated vertically upward within the mineral bed to begin the formation of an addi-tional mining cavity;
Figure 6 is a cross-sectional view depicting the method of forming multiple boreholes within the mineral formation which are laterallly spaced from one another and illustrating the manner in which the tailings Erom the currently mined borehole are returned to fill the mining cavity of a previously mined borehole.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
_ Referring tc Figure 1, there is shown a mineral for mation 10 composed generally of an overburden 12 and mineral bed 14 which by way of example comprises a unconsolidated tar sand formation. Preparatory to the actual hydraulic mining operation, the ini~ial step in the method of the present invention is a formation of a borehole 16 which initiates ad~acent ground surface 18 and preferably extends a short distance beyond the interface 20 between the over-burden 12 and mineral bed 14. The borehole 18 may be formed by any conventional method but by way of preferred embodiment is produced by use of an auger sized to yield an effective borehole diameter of approximately 20 inches.
Subsequent to the formation of the borehole 16, a tubular drill casing 22 having a maximum outside diameter slightly less than the diameter of the borehole 18 is inserted within the borehole 18 extending from ground surface 18 to a position adjacent the lower end of the borehole 16. The casing 22 is preferably formed of metal or cement and is maintained stationary within the formation 10 by conventional means such as casing shoes (not shown). As will be recog-nized, due to the casing 22 extending throughout the length of the overburden 12~once installed, fall-in of the over-burden 12 into the borehole 16 is substanially eliminated.
1:1L78~9S
Subsequent to the implacement of the casing 22, the ne~t manipulate step of the present învention is the for-mation of an artificially stabilized or consolidated zone adjacent the interface 20 between the overburden 12 and mineral bed 14 which serves to provide subjacent support for the overburden 12 during the mining process. Refer-ring to Figure 2, the detailed structure and procedure utilized to produce this stabilized region may be described.
As shown, the casing 22 adjacent its lowermost end is pro-vided with a plurality of apertures 30 which extendradially outward through the cylindrical wall of the casing 22. The apertures 30 may be formed in the casing 22 either during manufacture of the casing and, hence, prior to insertion of the casing 22 within the borehole 18 or subse-quently after the casing is set in the Eormation 10 by useof conventional gun-perforation or jet-perforation tech-niques. As best shown in Figure 2, the plural apertures 30 are preferably located at a distance spaced from the lowermost end of the drill.casing 22 and positioned so as to be in the general plane of or slightly above the over-burden/mineral bed interface 20.
A mechanical packer 32 (indicated by the phantomlines in Figure 2) is inserted downward from ground surface 18 through the length of the casing 22 and rigidly positioned at the lower~ost end of the casing 32. Such mechanical packers are well-known in the art, and with reference to this particular application, is utilized to completely close off or block the lowermost end of the casing 22 at ~ an area vertically below the plural apertures 30. With the packer 32 implaced within the casing 22, a suitable bonding agent may be pumped under pressure, downward from ground surface 18 through the interior oE the casing 22 wherein it is directed through the apertures 30 and urged radially outward into the formation 10 (as indicated by the arrows in Figure 2). By controlling injection pressure as well as the volume of the bonding agent introduced into the formation, the bonding agent may be squeezed radially outward into the formation forming a disc-shaped region 40 ~L~L'i'8~9S
substantially co-axial about the borehole 16. A variety of bonding agents may be utilized for this purpose, and are characterized by remaining substantially pliable or fluid during the initial injection process to sufficiently migrate radially outward into the formation and subsequently cure or harden to bond the injected formation into a substantially regid consolidated region. Examples of such bonding agents are catalyst activated silica jells such as "SAND FIX", a registered trademark of the Halliburton Company for a multi-10 step organic chemical resin process, or "SAND SET", aregistered trademark of the Halliburton Company for a pre-mixed plastic compound which hardens to form a strong perMeable consolidation.
In the preferred embodiment, the effective diameter of 15 the artificially consolidated region 40 (and, thus, the amount of bonding agent injected into the formation 10), may be predetermined to insure thal: sufficient support will be yielded for the overburden 12 in an amount proportional to the amount of mineral bèd 14 desired to be mined in the 20 actual hydraulic mining process. ~owever, for the majority oE hydraulic mining applica~ions, Lt is anticipated that the effective diameter of the consolidated zone 40 will range from approximately 10 to 60 Eeet, thereby preventing any downward migration or subsidence of the overburden 12 25 into the mineral b2d 14.
Subsequent to the formation of the consolidated region 40, the mechanical packer 32 is removed from the interior of the drill casing 22 and a conventional drilling apparatus such as an auger (not shown) is lowered downward within the 30 casing 22 and utilized to extend or drill the borehole 16 deeper into the mineral formation 14. As best shown in Figure 3, the borehole 16 is preferably extended to the total depth desired to be mined in the mineral bed 14, typically ranging from 300 to 5,000 feet below ground surface.
35 Of course, the actual distance of the borehole will be dependent upon the height of the particular mineral bed 14.
With the borehole 16 extended to total depth within the mineral bed, a protective sleeve or shroud 42 is inserted _9_ 1~7~ 5 downward from ground surface 18 into the formation 10. The sleeve 42 is preferably formed of plural, tubular steel pipe sections which are connected in an end for end orien-tation. The ouside diameter of the pipe sleeve is sized slightly less than the inside diameter of the drill casing 22 while the inside diameter is slightly greater than the outside diameter of the mining tool 50 (shown in Figure 4).
As shown, the sleeve 42 extends throughout the entire of length of ~he casing 22 and substantially throughout the length of the borehole 16, terminating at a vertical distance spaced from the lower end of the borehole 16. The upper end of the sleeve 42 is preferably connected to a suitable lifting and/or lowering mechanism such as a hydraulic jack (not shown) which prevents the sleeve 42 from rotating in the ormation and permits the sleeve 42 to be selectively reciprocated axially throughout thevlength of the borehole 16.
With the consolidated region 42 formed adjacent the overburden/mineral bed interface 20 and the protective sleeve 42 positioned within the mi.neral bed 14, the hydraulic mining tool 50 (shown in Figure 4) may be inserted from ground surface 18 downward through the protective sleeve 42 to be disposed within the mineral bed 14, at a vertical elevation below the end of the protective sleeve 42. As is well knownin theart~e hydraulic mining tool is mounted at its uppermost end to a drill string 52 which includes internal conduits and piping (not shown) extending from ground surface 18 to the mining tool 50. In operation, the drill-string 52 and mining tool 50 is rotated by con-ventional means located above ground surface 18 and a high velocity liquid, such as water, is channeled downward through the internal conduits of the drill strin~ and dis-charged radiàlly outward through one or more venturi jets 54 formed on the mining tool 50 to dislodge the sand particles from the mineral bed 14. The dislodged sand par-icles form an aqueous slurry with the liquid discharge, which may be raised upward to ground surface by way of a pump disposed within the interior of the mining tool 50. A more detailed description of the operation of such hydraulic mining tools is disclosed in U.S. Patent No. 3,951,457 issued to Redford ~ 4 ~
:~ ) 'I~L7~3~L95 and my Canadian patent application 355,024, now Patent 1,130,200 entitled Downhole Pump with sOttOm Receptor.
In Figures 5A through 5D, the particular mining processes occuring as well as the benefits made possible by the method of the present invention may be recognized. As shown in Figure 5A, the mining tool 50 is initially positioned to extend to the total depth of the borehole 16 and is disposed directly within the mineral bed 14. It is an important 10 feature of the present invention that the lower end of the protective sleeve 42 is maintained at a height vertically above the venturi cutting jets 54 of the mining tool 50 which height corresponds to the particular height of the mineral bed 14 desired to be initially mined.
Positioned in such a manner, the hydraulic mining process is initiated with the mining tool 50 being rotated and the hydraulic mining fluid being discharged radially through the venturi jets 54 and into the formation 14 in the manner previou~ly described. During the initial period of the 20 mining process, the sand particle~; o the mineral bed 16 located in the vicinity of the mining tool 50 are dislodged and subsequently transported in a slurry mixture upward to ground surface 18, whereby a substantially conical shaped void or mining cavity 70 is formed within the mineral bed 14 25 (as illustrated in Fugure 5B). As the mining process continues the volume of the mining cavity 70 increases with the surrounding mineral bed 14 falling downward from the side surfaces of the cavity toward the bottom of the cavity (as depicted by the phantom lines in Figure 5C). This fall-in condition 30 within the mining cavity 70 is enhanced by the frictional drag forces exerted on the surrounding mineral bed 14 by the rotating mining tool 50 which disturb the relatively weak crementitious forces of the mineral bed 14. However, due to the non-rotating protective sleeve 42 forming a shroud over 35 the major portion of the drill string 52 of the mining tool 50, these frictional drag forces are exerted only in the particular area of the mineral bed in which the mining tool 50 extends beyond the sleeve 42 (i.e. the area desired to be mined within the mineral bed) and not through the entire 40 formation. As s~ch~ by axially positioning the protective 11~71~ 5 shroud 42 at a height above the mining tool 50, a controlled fall-in or compaction situation can be provided during the mining process. This controlled fall-in situation signifi-cantly prevents the catastrophic compaction heretofore experienced in the hydraulic mining of unconsolidated mineral formations.
Further, due to the protecti~e sleeve 42 extending along the major length of the drill string 52, in those instances when a complete compaction or fall-in situation 10 occurs, the pressure and, hence, the torque exerted on the mining tool apparatus is only exerted on the portion of the mining tool 50 and drill-string 52 extending beyond the end of the protective sleeve 42 and not along the entire length of the drill-string 52 as heretofore associated in the art.
15 Thus, even upon con~ronting a complete fall-in situation during the rnining operation, the maximum torque exerted on the mining tool 50 is maintained at a minimum which reduces, if not completely eliminates, the possibility of twist-off of the mining tool 50 during the minin~ operation.
Once the initial conical shaped mining cavity 70 is mined to a maximum volume, the mining t? 50 is raised vertically upward to an elevation above the initial cavity 70 as depicted in Figure 5D. As the mining ~ool 50 is raised vertically upward, the protective sleeve 42 is similarly 25 raised to a position above the mining tool 50 to define a second area within the mineral bed 14 which is desired to be mined. The hydraulic mining process may then again be initiated causing the formation of a second conical shaped mining cavity 70A in the mineral bed 14 which, as depicted 30 in Figure 5D, is spaced vertically above the initial cavity 70. As will be recognized, this process may be continued throughout the elevation of the mineral bed 14 thereby forming consecutive mining cavities 70, 70A, 70B, etc., within the mineral bed which are generally co-axial with 35 the borehole 16.
As the consecutive mining cavities 70, 70A, etc., are formed in the mineral bed 14 and progress upward toward the interface 20 between the overhurden 12 and mineral bed 14 !
the artificially consolidated region 40 (shown in Figure 6), S
serves to provide a platform-like structure which supports the overburden 12 and prevents any downward sifting of the overburden 12 into the borehole and mining cavity 70. As such, the overburden is maintained in its initial state or condition with only the mineral bed 14 being mined during the hydraulic mining process which further prevents any downward subsidance of the overburden 12. Once the entire depth of the mineral bed 14 is mined in such a manner, the minlng tool 50 and drill-string 52 may be removed from the borehole 16 in a relatively simple procedure with the protective shroud 42 bearing the major compressive forces of the overburden 12. Subsequently, the protective sleeve 42 may be additionally removed from the formation or alter-natively left therein and sacrificed within the formation.
By use of the process of the present invention, it will be recognized that the entire mineral formation 10 may be initially provided witha plurality of boreholes 16A, 16B, and 16C as shown in Figure 6. As a hydraulic mining process is conducted in one of plural boreholes 16C, the mined material transported upward to ground surface may be separated by conventional means and the non-~mineral bearing drill tailings i.e. (sand particles) may be returned directly into a previously mined borehole 16B. This process may be continued for each of the previously mined boreholes 16A
such that the tailings removed from the mineral bcd 16 are continously returned back to the subterranean formation.
As such, the minority of any adverse environmental considera-tion caused by the dril tailing are eliminated by use of the -present invention.
In summary, the present invention comprises a substan-tial improvement in the art of hydraulic mining which is specifically adpated for economical recovery of unconsolidated mineral formations which eliminates the downward sifting of overburden into the mining cavity, prevents substantial torque being exerted on the tool, and provides a controlled rate of recovery of the mineral formation.
BACKGROUND OF THE PRESENT IN~ENTION
The present invention relates generally to hydraulic mining tool apparatus and more particularly to an improved hydraulic mining tool and method of hydraulically mining unconsolidated mineral formations such as tar sands.
Recent technology has been developed which permits the recovery of subterranean mineral deposits by use of hydrau-lic mining techniques. Basically, such hydraulic mining techniques are characterized by the use of a high velocity liquid stream which is discharged directly into the sub-terranean mineral deposit to dislodge minerals from their surrounding mineral bed. The freed minerals form a resul-tant slurry with the discharged liquid stream which may be pumped by various means, upward to ground surface and sub-sequently processed by surface separation systems. As the slurry is removed from the formation, a mining cavity or void is formed in the mineral bed which dependent upon the size and type of the particular formation, may extend to 100 feet in diameter throughout the height of the mineral bed. Examples of such hydraulic mining tools are disclosed in U.S. Patent 3,951,457 issued to Redford, U.S. Patent No. 3,439,953 issued to Pfefferle, and my Canadian Patent 1,130,020 entitled Downhole PumP with Bottom Receptor.
As to date, such hydraulic mining techniques have been primarily utilized to recover minerals such as uranium, coal, or potash which typically possess sufficient consoli-dation in their natural formation state so that as the mining cavity or void is formed in the subterranean forma-tion, the surrounding mineral bed remains in its stabilized consolidated condition, thereby defining a "clean" mining cavity. Thus, in such consolidated formations, the over-burden is continuously supported by the consolidated mineral bed and the hydraulic mining tool may be freely rotated and vertically reciprocated within the borehole and mining cavity throughout the mining process. However, in the hydraulic mining of unconsolidated mineral formations such as tar sands,unique mining problems exist which to a great ~ ?
extent has rendered the existing hydraulic mining tool technology commercially infeasible.
In contrast to the above mentioned consolidated mineral formations, unconsolidated formations such as tar sands, typically are non-uniform in composition and often fail to possess the necessary degree of stabilization to maintain a "clean" mining cavity during the hydraulic mining opera-tion. This failure of the ~mconsolidated formations and in particular tar sand formations, is due to the individual sand grains of the formation being stabilized primarily by the compressive forces generated by the weight of the over-burden, with the cementation forces existing between individual sand grains being extremely small in magnitude.
As the subjacent portions of the tar sand mineral bed are removed during the hydraulic mining process, the overburden compressive force balance within the mineral formation is disturbed which, due to only minimal cementation forces existing between the individual sand grain, often results in a "cave-in" or "compaction situation" whereby the sur-rounding mineral bed catastrophically falls in and aroundthe drill string and into the mining cavlty.
When hydraulically mining in relatively shallow unconsolidated formations, the occurrence of such a com-paction situation within the mineral bed often permits the overburden to migrate downward into the borehole and mining cavity, wherein it mixes with the mined mineral slurry and is subsequently transported upward to ground surface during the mining process. As will be recognized, the mining of the non-mineral bearing overburden reduces the overall efficiency of the mining process and if substantial, renders the cost effectiveness of the hydraulic mining process commercially infeasible. Further, in those instances where the downward migration of the overburden is acute, a ~eneral subsidance of the overburden may be experienced whereby the overburden fails to support the necessary surface mining equipment.
Alternatively when mining in deep unconsolidated mineral formations (i.e., greater than 500 feet below ground surface), individual sand grains located proximal the borehole often 3 17B1~5 dislodged from the mineral bed by frictional drag forces exerted by the rotating mining tool and drill string.
Through prolonged duration, these frictional drag forces often disturb the fragile cementation forces existing between sand grains and result in the entire surrounding mineral bed falling in and compacting around the mining tool. Due to the depth in which the mining operation is occuring, substantial pressure is applied along the entire length of the drill string which generates substantial torque on the mining tool during rotation. Such high tortional forces have heretofore required the intermittent shut down of the drilling operation or,in extreme instances, have caused a complete structural failure or twist off of the mining tool within the formation. Such intermittent discontinuance of the mining operation significantly de-creases overall operating efficiency while a twist-off condition typically results in the mining tool being irretrievably lost within the mineral formation.
Thus, there exists a substantial need in the art for an improved hydraulic mining methodand apparatus specific-ally adapted for use in unconsolidated mineral formations which prevents downward migration oE the overburden, reduces frictional drag forces exerted on the mineral bed, and prevents extremely high tortional forces being generated on the mining tool during the hydraulic mining operation.
SUMMARY OF THE PRESENT INVENTION
The present invention comprises an improved apparatus and method of hydraulically mining which specifically addresses and alleviates the above referenced deficiencies associated in the hydraulic mining of unconsolidated mineral formations. More particularly, the present inven-tion comprises the formation of a consolidated, stabilized region or zone adjacent the overburden/mineral bed inter-face which extends radially outward into the formation in a generally disc-shaped configuration. In the preEerred ~17~195 embodiment, this stabilized zone is formed by injecting a suitable liquid bonding agent radially outward in the formation which after a sufficient curing period, bonds the individual overburden particles together to yield a consolidated, stabilized region. By such a procedure, the stabilized region forms in effect a rigid platform which artificially increases the cementation forces existing between the individual formation particles thereby increas-ing the support of the overburden and preventing the down-ward migration of the same during the mining operation.
In addition, the present invention contemplates theuse of a non-rotating protective sleeve which is telescop-ingly positioned along the length of the drill-string extending from ground surface to a location adjacent the mining tool. By use of the non-rotating protective sleeve, the mineral bed in the area adjacent the length of the borehole is substantially isolated from rictional drag forces caused by the rotation of the drill string and, hence, the cementitious forces existing between the individual sand ~0 grains o the ~ormations are not disturbed. As such, the possibility of a "faLl-in" or "cornpaction situation" within the formation is substantially reduced.
In addition to the reduced drag-force benefits made possible by its use, the protective sleeve forms a protective shroud surrounding the length of the drill-string which upon confronting a fall-in condition, shields the major length of the drill-string from direct interaction with the compressive forces exerted by the mineral formation.
Hence, even upon encountering a fall in condition during the mining of deep mineral formations the tortional forces exerted upon the mining tool are maintained at a minimum value. In addition, the protective sleeve permits the rapid withdrawal of the mining tool from the formation and if necessary may be sacrificed and left within the formation while recovering the mining tool and drill-string.
Further, the present invention discloses a novel method of hydraulically mining an entire mineral bearing area or oil field wherein multiple boreholes are formed in ~ ~ 7~ 9 S
the formation at laterally spaced intervals with the spent tailings from the currently mined borehole being returned into the previously mined borehole cavity. As such, environmental pollution considerations are reduced and the surface configuration and habitation of the entire oil field drilling site is maintained substantially in it's natural state.
DESCRIPTION OF DRAWINGS
These as well as other features of the present inven-tions will become more apparent upon reference to the drawings wherein;
~5 Figure 1 is a cross-sectional view taken through a mineral formation depicting the overburden and mineral bed and illustrating the initial step of drilling a borehole from ground surface to a depth adjacent the interface between the overburden and mineral bed;
Figure 2 is an enlarged cross sectional view taken about the in~erface between the overburden and mineral bed oE Figure 1 and depicting the manner in which the stabi-lized consolidated region is formed in the formation;
Figure 3 is a cross-sectional view of the mineral formation depicting the subsequent step of extending the borehole downward into the mineral bed and the insertion of the protective sleeve within the borehole;
Figure 4 isan enlarged cross-sectional view of the mineral bed depicting the relative orientation of the mining tool and drill string with the protective sleeve;
Figure 5A is a schematic representation depicting the position of the hydraulic mining tool and protective sleeve at the initiation of the actual hydraulic mining process;
Figure 5B is a schematic representation of the mineral bed depicting the initial formation of the mining cavity cavity within the formation;
Figure 5C is a schematic representation of the mineral bed depicting the configuration of the mining cavity after a prolonged mining operation;
B1~5 Figure 5D is a schematic representation of the mineral bed illustrating the manner in which the mining tool and protective sleeve may be reciprocated vertically upward within the mineral bed to begin the formation of an addi-tional mining cavity;
Figure 6 is a cross-sectional view depicting the method of forming multiple boreholes within the mineral formation which are laterallly spaced from one another and illustrating the manner in which the tailings Erom the currently mined borehole are returned to fill the mining cavity of a previously mined borehole.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
_ Referring tc Figure 1, there is shown a mineral for mation 10 composed generally of an overburden 12 and mineral bed 14 which by way of example comprises a unconsolidated tar sand formation. Preparatory to the actual hydraulic mining operation, the ini~ial step in the method of the present invention is a formation of a borehole 16 which initiates ad~acent ground surface 18 and preferably extends a short distance beyond the interface 20 between the over-burden 12 and mineral bed 14. The borehole 18 may be formed by any conventional method but by way of preferred embodiment is produced by use of an auger sized to yield an effective borehole diameter of approximately 20 inches.
Subsequent to the formation of the borehole 16, a tubular drill casing 22 having a maximum outside diameter slightly less than the diameter of the borehole 18 is inserted within the borehole 18 extending from ground surface 18 to a position adjacent the lower end of the borehole 16. The casing 22 is preferably formed of metal or cement and is maintained stationary within the formation 10 by conventional means such as casing shoes (not shown). As will be recog-nized, due to the casing 22 extending throughout the length of the overburden 12~once installed, fall-in of the over-burden 12 into the borehole 16 is substanially eliminated.
1:1L78~9S
Subsequent to the implacement of the casing 22, the ne~t manipulate step of the present învention is the for-mation of an artificially stabilized or consolidated zone adjacent the interface 20 between the overburden 12 and mineral bed 14 which serves to provide subjacent support for the overburden 12 during the mining process. Refer-ring to Figure 2, the detailed structure and procedure utilized to produce this stabilized region may be described.
As shown, the casing 22 adjacent its lowermost end is pro-vided with a plurality of apertures 30 which extendradially outward through the cylindrical wall of the casing 22. The apertures 30 may be formed in the casing 22 either during manufacture of the casing and, hence, prior to insertion of the casing 22 within the borehole 18 or subse-quently after the casing is set in the Eormation 10 by useof conventional gun-perforation or jet-perforation tech-niques. As best shown in Figure 2, the plural apertures 30 are preferably located at a distance spaced from the lowermost end of the drill.casing 22 and positioned so as to be in the general plane of or slightly above the over-burden/mineral bed interface 20.
A mechanical packer 32 (indicated by the phantomlines in Figure 2) is inserted downward from ground surface 18 through the length of the casing 22 and rigidly positioned at the lower~ost end of the casing 32. Such mechanical packers are well-known in the art, and with reference to this particular application, is utilized to completely close off or block the lowermost end of the casing 22 at ~ an area vertically below the plural apertures 30. With the packer 32 implaced within the casing 22, a suitable bonding agent may be pumped under pressure, downward from ground surface 18 through the interior oE the casing 22 wherein it is directed through the apertures 30 and urged radially outward into the formation 10 (as indicated by the arrows in Figure 2). By controlling injection pressure as well as the volume of the bonding agent introduced into the formation, the bonding agent may be squeezed radially outward into the formation forming a disc-shaped region 40 ~L~L'i'8~9S
substantially co-axial about the borehole 16. A variety of bonding agents may be utilized for this purpose, and are characterized by remaining substantially pliable or fluid during the initial injection process to sufficiently migrate radially outward into the formation and subsequently cure or harden to bond the injected formation into a substantially regid consolidated region. Examples of such bonding agents are catalyst activated silica jells such as "SAND FIX", a registered trademark of the Halliburton Company for a multi-10 step organic chemical resin process, or "SAND SET", aregistered trademark of the Halliburton Company for a pre-mixed plastic compound which hardens to form a strong perMeable consolidation.
In the preferred embodiment, the effective diameter of 15 the artificially consolidated region 40 (and, thus, the amount of bonding agent injected into the formation 10), may be predetermined to insure thal: sufficient support will be yielded for the overburden 12 in an amount proportional to the amount of mineral bèd 14 desired to be mined in the 20 actual hydraulic mining process. ~owever, for the majority oE hydraulic mining applica~ions, Lt is anticipated that the effective diameter of the consolidated zone 40 will range from approximately 10 to 60 Eeet, thereby preventing any downward migration or subsidence of the overburden 12 25 into the mineral b2d 14.
Subsequent to the formation of the consolidated region 40, the mechanical packer 32 is removed from the interior of the drill casing 22 and a conventional drilling apparatus such as an auger (not shown) is lowered downward within the 30 casing 22 and utilized to extend or drill the borehole 16 deeper into the mineral formation 14. As best shown in Figure 3, the borehole 16 is preferably extended to the total depth desired to be mined in the mineral bed 14, typically ranging from 300 to 5,000 feet below ground surface.
35 Of course, the actual distance of the borehole will be dependent upon the height of the particular mineral bed 14.
With the borehole 16 extended to total depth within the mineral bed, a protective sleeve or shroud 42 is inserted _9_ 1~7~ 5 downward from ground surface 18 into the formation 10. The sleeve 42 is preferably formed of plural, tubular steel pipe sections which are connected in an end for end orien-tation. The ouside diameter of the pipe sleeve is sized slightly less than the inside diameter of the drill casing 22 while the inside diameter is slightly greater than the outside diameter of the mining tool 50 (shown in Figure 4).
As shown, the sleeve 42 extends throughout the entire of length of ~he casing 22 and substantially throughout the length of the borehole 16, terminating at a vertical distance spaced from the lower end of the borehole 16. The upper end of the sleeve 42 is preferably connected to a suitable lifting and/or lowering mechanism such as a hydraulic jack (not shown) which prevents the sleeve 42 from rotating in the ormation and permits the sleeve 42 to be selectively reciprocated axially throughout thevlength of the borehole 16.
With the consolidated region 42 formed adjacent the overburden/mineral bed interface 20 and the protective sleeve 42 positioned within the mi.neral bed 14, the hydraulic mining tool 50 (shown in Figure 4) may be inserted from ground surface 18 downward through the protective sleeve 42 to be disposed within the mineral bed 14, at a vertical elevation below the end of the protective sleeve 42. As is well knownin theart~e hydraulic mining tool is mounted at its uppermost end to a drill string 52 which includes internal conduits and piping (not shown) extending from ground surface 18 to the mining tool 50. In operation, the drill-string 52 and mining tool 50 is rotated by con-ventional means located above ground surface 18 and a high velocity liquid, such as water, is channeled downward through the internal conduits of the drill strin~ and dis-charged radiàlly outward through one or more venturi jets 54 formed on the mining tool 50 to dislodge the sand particles from the mineral bed 14. The dislodged sand par-icles form an aqueous slurry with the liquid discharge, which may be raised upward to ground surface by way of a pump disposed within the interior of the mining tool 50. A more detailed description of the operation of such hydraulic mining tools is disclosed in U.S. Patent No. 3,951,457 issued to Redford ~ 4 ~
:~ ) 'I~L7~3~L95 and my Canadian patent application 355,024, now Patent 1,130,200 entitled Downhole Pump with sOttOm Receptor.
In Figures 5A through 5D, the particular mining processes occuring as well as the benefits made possible by the method of the present invention may be recognized. As shown in Figure 5A, the mining tool 50 is initially positioned to extend to the total depth of the borehole 16 and is disposed directly within the mineral bed 14. It is an important 10 feature of the present invention that the lower end of the protective sleeve 42 is maintained at a height vertically above the venturi cutting jets 54 of the mining tool 50 which height corresponds to the particular height of the mineral bed 14 desired to be initially mined.
Positioned in such a manner, the hydraulic mining process is initiated with the mining tool 50 being rotated and the hydraulic mining fluid being discharged radially through the venturi jets 54 and into the formation 14 in the manner previou~ly described. During the initial period of the 20 mining process, the sand particle~; o the mineral bed 16 located in the vicinity of the mining tool 50 are dislodged and subsequently transported in a slurry mixture upward to ground surface 18, whereby a substantially conical shaped void or mining cavity 70 is formed within the mineral bed 14 25 (as illustrated in Fugure 5B). As the mining process continues the volume of the mining cavity 70 increases with the surrounding mineral bed 14 falling downward from the side surfaces of the cavity toward the bottom of the cavity (as depicted by the phantom lines in Figure 5C). This fall-in condition 30 within the mining cavity 70 is enhanced by the frictional drag forces exerted on the surrounding mineral bed 14 by the rotating mining tool 50 which disturb the relatively weak crementitious forces of the mineral bed 14. However, due to the non-rotating protective sleeve 42 forming a shroud over 35 the major portion of the drill string 52 of the mining tool 50, these frictional drag forces are exerted only in the particular area of the mineral bed in which the mining tool 50 extends beyond the sleeve 42 (i.e. the area desired to be mined within the mineral bed) and not through the entire 40 formation. As s~ch~ by axially positioning the protective 11~71~ 5 shroud 42 at a height above the mining tool 50, a controlled fall-in or compaction situation can be provided during the mining process. This controlled fall-in situation signifi-cantly prevents the catastrophic compaction heretofore experienced in the hydraulic mining of unconsolidated mineral formations.
Further, due to the protecti~e sleeve 42 extending along the major length of the drill string 52, in those instances when a complete compaction or fall-in situation 10 occurs, the pressure and, hence, the torque exerted on the mining tool apparatus is only exerted on the portion of the mining tool 50 and drill-string 52 extending beyond the end of the protective sleeve 42 and not along the entire length of the drill-string 52 as heretofore associated in the art.
15 Thus, even upon con~ronting a complete fall-in situation during the rnining operation, the maximum torque exerted on the mining tool 50 is maintained at a minimum which reduces, if not completely eliminates, the possibility of twist-off of the mining tool 50 during the minin~ operation.
Once the initial conical shaped mining cavity 70 is mined to a maximum volume, the mining t? 50 is raised vertically upward to an elevation above the initial cavity 70 as depicted in Figure 5D. As the mining ~ool 50 is raised vertically upward, the protective sleeve 42 is similarly 25 raised to a position above the mining tool 50 to define a second area within the mineral bed 14 which is desired to be mined. The hydraulic mining process may then again be initiated causing the formation of a second conical shaped mining cavity 70A in the mineral bed 14 which, as depicted 30 in Figure 5D, is spaced vertically above the initial cavity 70. As will be recognized, this process may be continued throughout the elevation of the mineral bed 14 thereby forming consecutive mining cavities 70, 70A, 70B, etc., within the mineral bed which are generally co-axial with 35 the borehole 16.
As the consecutive mining cavities 70, 70A, etc., are formed in the mineral bed 14 and progress upward toward the interface 20 between the overhurden 12 and mineral bed 14 !
the artificially consolidated region 40 (shown in Figure 6), S
serves to provide a platform-like structure which supports the overburden 12 and prevents any downward sifting of the overburden 12 into the borehole and mining cavity 70. As such, the overburden is maintained in its initial state or condition with only the mineral bed 14 being mined during the hydraulic mining process which further prevents any downward subsidance of the overburden 12. Once the entire depth of the mineral bed 14 is mined in such a manner, the minlng tool 50 and drill-string 52 may be removed from the borehole 16 in a relatively simple procedure with the protective shroud 42 bearing the major compressive forces of the overburden 12. Subsequently, the protective sleeve 42 may be additionally removed from the formation or alter-natively left therein and sacrificed within the formation.
By use of the process of the present invention, it will be recognized that the entire mineral formation 10 may be initially provided witha plurality of boreholes 16A, 16B, and 16C as shown in Figure 6. As a hydraulic mining process is conducted in one of plural boreholes 16C, the mined material transported upward to ground surface may be separated by conventional means and the non-~mineral bearing drill tailings i.e. (sand particles) may be returned directly into a previously mined borehole 16B. This process may be continued for each of the previously mined boreholes 16A
such that the tailings removed from the mineral bcd 16 are continously returned back to the subterranean formation.
As such, the minority of any adverse environmental considera-tion caused by the dril tailing are eliminated by use of the -present invention.
In summary, the present invention comprises a substan-tial improvement in the art of hydraulic mining which is specifically adpated for economical recovery of unconsolidated mineral formations which eliminates the downward sifting of overburden into the mining cavity, prevents substantial torque being exerted on the tool, and provides a controlled rate of recovery of the mineral formation.
Claims (12)
1. A method of hydraulically mining a subterranean mineral deposit having an overburden and a subjacent mineral bed, comprising the steps of:
drilling a borehole from ground surface into said overburden toward said mineral bed;
artificially consolidating a region of said mineral deposit located adjacent the interface between said overburden and mineral bed and extending generally radially outward from said bore hole through a distance commensurate with the radial distance of said mineral bed desired to be mined to support the overburden to prevent migration of said overburden into said mineral bed;
inserting a mining tool within said borehole and into said mineral bed to hydraulically dislodge a portion of said mineral bed located at an elevation below said region and form a resultant mineral slurry; and transporting said resultant mineral slurry through said mining tool to said ground surface.
drilling a borehole from ground surface into said overburden toward said mineral bed;
artificially consolidating a region of said mineral deposit located adjacent the interface between said overburden and mineral bed and extending generally radially outward from said bore hole through a distance commensurate with the radial distance of said mineral bed desired to be mined to support the overburden to prevent migration of said overburden into said mineral bed;
inserting a mining tool within said borehole and into said mineral bed to hydraulically dislodge a portion of said mineral bed located at an elevation below said region and form a resultant mineral slurry; and transporting said resultant mineral slurry through said mining tool to said ground surface.
2. The method of Claim 1 wherein said consolidating step comprises:
injecting a bonding-agent axially through said borehole land and radially outward into said region to locally increase the cementation forces existing within said mineral deposit.
injecting a bonding-agent axially through said borehole land and radially outward into said region to locally increase the cementation forces existing within said mineral deposit.
3. The method of Claim 2 wherein said injecting step comprises the further step of:
forcing a viscuous bonding agent radially outward from said bore hole into said region; and allowing said viscous bonding agent to cure and artifically increase said cementation forces existing within said mineral deposit at said region.
forcing a viscuous bonding agent radially outward from said bore hole into said region; and allowing said viscous bonding agent to cure and artifically increase said cementation forces existing within said mineral deposit at said region.
4. The method of Claim 1 further comprising of:
positioning an elongate sleeve into said borehole to extend substantially throughout the length of said mining tool to shield said mining tool from compressive forces exerted by said mineral deposit.
positioning an elongate sleeve into said borehole to extend substantially throughout the length of said mining tool to shield said mining tool from compressive forces exerted by said mineral deposit.
5. The method of Claim 4 further comprising the step of:
maintaining said elongate sleeve stationary while rotating said mining tool, to reduce frictional drag forces exerted by said rotating mining tool on said mineral deposit.
maintaining said elongate sleeve stationary while rotating said mining tool, to reduce frictional drag forces exerted by said rotating mining tool on said mineral deposit.
6. The method of claim 5 further comprising the step of:
telescoping said sleeve axially along the length of said mining tool to selectively control the size of said portion of said mineral bed desired to be mined.
telescoping said sleeve axially along the length of said mining tool to selectively control the size of said portion of said mineral bed desired to be mined.
7. A method of hydraulically mining a subterranean mineral deposit, comprising the steps of:
forming a borehole extending from ground surface into said mineral deposit;
inserting a drill string having a mining tool mounted on the lower end thereof within said borehole to hydraulically dislodge a portion of said mineral deposit desired to be mined and form a resultant slurry;
positioning an elongate sleeve substantially coaxially along the length of said drill string to shield said drill string from compressive forces exerted by said mineral deposit;
telescoping said elongate sleeve axially along the length of said drill string to an elevation substantially equal to the maximum vertical elevation of said portion of said mineral bed desired to be mined;
maintaining said elongate sleeve stationary while rotating said drill string and mining tool within said mineral bed; and transporting said resultant slurry to ground surface through said mining tool.
forming a borehole extending from ground surface into said mineral deposit;
inserting a drill string having a mining tool mounted on the lower end thereof within said borehole to hydraulically dislodge a portion of said mineral deposit desired to be mined and form a resultant slurry;
positioning an elongate sleeve substantially coaxially along the length of said drill string to shield said drill string from compressive forces exerted by said mineral deposit;
telescoping said elongate sleeve axially along the length of said drill string to an elevation substantially equal to the maximum vertical elevation of said portion of said mineral bed desired to be mined;
maintaining said elongate sleeve stationary while rotating said drill string and mining tool within said mineral bed; and transporting said resultant slurry to ground surface through said mining tool.
8. The method of Claim 7 comprising the further step of:
rotating said mining tool within said mineral bed; and maintaining said elongate sleeve stationary at said position while said mining tool is rotated.
rotating said mining tool within said mineral bed; and maintaining said elongate sleeve stationary at said position while said mining tool is rotated.
9. A method of hydraulically mining an unconsolidated subterranean mineral deposit having an overburden and a subjacent mineral bed, comprising the steps of:
forming a borehole extending from ground surface into said overburden toward said mineral bed;
artificially increasing the cementation forces existing within a localized area of said overburden to form a generally disc-shaped stabilized region extending radially outward from said borehole through a distance proportional to the size of said mineral bed desired to be mined to prevent said overburden from subsiding toward said mineral bed;
inserting a mining tool within said borehole to extend through said region and into said mineral bed to hydraulically dislodge minerals from said mineral bed desired to be mined and form a resultant slurry; and transporting said resultant mineral slurry through said mining tool to said ground surface.
forming a borehole extending from ground surface into said overburden toward said mineral bed;
artificially increasing the cementation forces existing within a localized area of said overburden to form a generally disc-shaped stabilized region extending radially outward from said borehole through a distance proportional to the size of said mineral bed desired to be mined to prevent said overburden from subsiding toward said mineral bed;
inserting a mining tool within said borehole to extend through said region and into said mineral bed to hydraulically dislodge minerals from said mineral bed desired to be mined and form a resultant slurry; and transporting said resultant mineral slurry through said mining tool to said ground surface.
10. The method of Claim 9 wherein said increasing step comprises:
injecting a time-curing bonding agent radially outward from said borehold into said localized area of said overburden to form a generally disc-shaped cementatious layer within said overburden having sufficient integrity to support said overburden without subsidence as said mineral slurry is trans-ported from said mineral bed.
injecting a time-curing bonding agent radially outward from said borehold into said localized area of said overburden to form a generally disc-shaped cementatious layer within said overburden having sufficient integrity to support said overburden without subsidence as said mineral slurry is trans-ported from said mineral bed.
11. A method of hydraulically mining a subterranean mineral deposit having an overburden and a subjacent mineral bed, comprising the steps of:
forming a bore hole extending from ground surface through the overburden into the mineral deposit;
inserting a casing in the borehole; and injecting a bonding agent through apertures in the casing wall into a region of the mineral deposit adjacent the overburden to form a generally disc-shaped stabilized region around the casing for supporting the overburden; and introducing a fluid into the casing to hydraulically mine the subterranean mineral deposit.
forming a bore hole extending from ground surface through the overburden into the mineral deposit;
inserting a casing in the borehole; and injecting a bonding agent through apertures in the casing wall into a region of the mineral deposit adjacent the overburden to form a generally disc-shaped stabilized region around the casing for supporting the overburden; and introducing a fluid into the casing to hydraulically mine the subterranean mineral deposit.
12. The method of Claim 11, further including the steps of:
placing a drilling apparatus within the casing to drill the mineral formation to extend the bore hole to a predetermined depth to be mined in the mineral deposit;
inserting a protective sleeve through the casing into the bore hole in the mineral deposit;
inserting a mining tool mounted on a drill string through the protective sleeve into the mineral deposit to hydraulically dislodge a portion of the mineral deposit located at an elevation below the stabilized region and form a mineral slurry, the protective sleeve shielding the drill string from compressive forces exerted by the mineral deposit.
placing a drilling apparatus within the casing to drill the mineral formation to extend the bore hole to a predetermined depth to be mined in the mineral deposit;
inserting a protective sleeve through the casing into the bore hole in the mineral deposit;
inserting a mining tool mounted on a drill string through the protective sleeve into the mineral deposit to hydraulically dislodge a portion of the mineral deposit located at an elevation below the stabilized region and form a mineral slurry, the protective sleeve shielding the drill string from compressive forces exerted by the mineral deposit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000398020A CA1178195A (en) | 1982-03-10 | 1982-03-10 | Apparatus and method of hydraulically mining unconsolidated mineral formations |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000398020A CA1178195A (en) | 1982-03-10 | 1982-03-10 | Apparatus and method of hydraulically mining unconsolidated mineral formations |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1178195A true CA1178195A (en) | 1984-11-20 |
Family
ID=4122261
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000398020A Expired CA1178195A (en) | 1982-03-10 | 1982-03-10 | Apparatus and method of hydraulically mining unconsolidated mineral formations |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1178195A (en) |
-
1982
- 1982-03-10 CA CA000398020A patent/CA1178195A/en not_active Expired
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