Softwall mining method and device

Abstract
A softwall mining method and device. Each of a plurality of mining devices comprise a supporting portion, an earth moving portion and a coupling mechanism for advancing the earth moving portion into a mining face, and for advancing the supporting portion toward the earth moving portion. Supporting portions of the devices are locked together to anchor movement of the earth moving portions, and earth moving portions of the devices are separately locked together to anchor the movement of the supporting portions.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention pertains in general to the field of mining and, in particular, to a novel device and method for mining slurryable, shallow mineral deposits with or without earthy overburden in a longwall fashion.




2. Description of the Prior Art




Surface mining is and has historically been employed to recover stratified minerals under overburden to economic depths. Underground mining is traditionally employed when overburden depths exceed those economically removable by surface mining or when major surface disturbance is unacceptable.




Prior inventions have been patented for longwall mining of reserves using trenched entry where overburden is sufficiently competent to bridge over longwall shearing and conveying equipment and where floor strata are competent to withstand mining stresses. (See Simpson, U.S. Pat. No. 4,017,122.) Simpson does not accommodate soft, plastic, fluid, loose, unstable, clayey, sandy, dirt, soil, or similar (earthy) ground conditions often encountered in mining shallow ore deposits. Earthy conditions can allow the mine roof to fall ahead of shield supports or allow the floor to heave up behind the face conveyor ahead of the shield pontoons. This creates safety hazards, dilution of ores, and expensive control installation.




For surface mining and windrow reclaim, it has long been known to sluice the mining face or the mined earth to form a slurry for transport. A sluicing pit is created adjacent a mining pit mined with a dragline or other surface excavator. The excavator drops excavated earth into the sluicing pit. A water canon is provided at the sluicing pit to create a slurry, which is pumped away. As the excavator excavates, however, it moves farther away from the sluicing pit, increasing the time required to move the excavated earth to the pit, or requiring periodic reconstruction of the pit.




Some ores, such as phosphate bearing clay, are accompanied by a high degree of moisture. Traditional sluicing methods adds a significant amount of additional moisture, such that the solids content of the resulting slurry may be only 20 to 30%. Moving so much water is expensive. Moreover, in surface mining of such ores, the water tends to fill the mining pit making it difficult to retrieve the ore with excavating apparatus, such as the dragline.




Some ores, such as phosphate bearing clay, are contained within a horizontal plane that does not follow the inclination of the surrounding geologic strata. Prior art methods have not provided a convenient means for maintaining a horizontal mining plane.




BRIEF SUMMARY OF THE INVENTION




The idea of adapting longwall mining equipment and methods to recover ore from slurryable deposits with earthy overburden is novel. The term “softwall” is a new term applicable to this type of mining.




In particular, the subject invention is directed at phosphate matrix mining. A plurality of elongated, substantially parallel, main trenches extend the full length of area to be mined. The trenches are nominally 1,000 feet apart. Heading trenches substantially perpendicular to the main panel trenches are excavated for placement and removal of the mining equipment. The trenches are formed by excavating the overburden materials to the top surface of the mineral bed. The mineral bed in the trench is separately excavated and beneficially recovered. Trench side wall slopes are as steep as is geologically reasonable and safe to minimize excavation.




Forming a header trench leaves an exposed longwall. The softwall mining equipment is installed in the header trench. The phosphate is then mined, for example, by slurrying the ore as the mining equipment moves in a direction generally parallel to the main panel trenches. The slurried ore flows into the main panel trenches where it is removed to the surface for processing.




The softwall mining equipment includes an outer shell to support the overburden stresses. Forward motion is created by extending a cutting head into the ore reserve and retracting said head in such a manner as to pull the outer shell forward.




Unsupported overburden behind the outer shell is encouraged to fill the cavity. Where backfilling is used, materials are injected through the outer shell. Operation of the softwall equipment and backfilling is performed automatically from controls in the trench or on the surface.




When softwall mining equipment has traveled a predetermined distance to the next header trench, the equipment is removed and placed in another header trench for mining additional ore. Trenches not scheduled for further use would be reclaimed.




Alternatively, the equipment can be repositioned at the exit header and again advanced in the opposite direction to mine the next lower level of the ore seam.




Another alternative would be to utilize several sets of softwall mining equipment in a seam thicker than one set of equipment can mine. The uppermost level would be mined first. Adjacent lower levels would be mined with predetermined horizontal separation distances between sets of equipment.




Yet another alternative, where ore can be slumped, is to position the softwall mining equipment at or near the bottom of the ore seam. With or without forward injection of fluids into the ore seam, the slurried ore would slump into the softwall mining equipment and move into the main panel trenches.




Instead of using parallel main panel trenches and a common header trench, a single main trench can be used with a header constructed in a “T” manner. One set of softwall mining equipment would be placed in each header branch of the “T” with slurried ore feed to the trunk main panel trench.




The equipment can also operate in a spiral fashion following main panel trenches constructed to curl in a continuous pattern through the ore reserve.




In another aspect of the invention, individual softwall mining devices may be locked together to provide for advancing portions of the devices into the mining face without requiring the rear support typically provided by overburden for, e.g., surface mining and windrow reclaim.




In yet another aspect of the invention, selected softwall mining devices employed for, e.g., surface mining or windrow reclaim may be provided with a water canon or other water nozzle for preliminarily wetting the mining face or excavated earth.




Besides the objects and advantages described above, the softwall mining device of the present invention is also believed:




a. to provide a more economical means of mining slurryable ores;




b. to provide a means of removing ores by longwall methods where earthy overburden is present and where it is not;




c. to provide a means of longwall mining without use of panel development and outbye roof support;




d. to provide an alternative means of mining sticky clay ore; and




e. to provide a means of mining material varying from solid to liquid phases without special concern for the phase.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

shows an isometric view of a softwall mining device according to the invention.





FIG. 2

shows a plan or top view of the softwall mining device of the invention.





FIG. 3

shows an end view of the softwall mining device of

FIGS. 1 and 2

.





FIG. 4

shows an end view of the cutting head of the face sluicing chamber.





FIG. 4A

shows a more detailed view of the top portion of the cutting head seen in FIG.


4


.





FIG. 4B

shows a more detailed view of the bottom portion of the cutting head seen in FIG.


4


.





FIG. 4C

shows an en d view of the cutting head of a face sluicing chamber including an auger to promote removal of mined material.





FIG. 5

shows a plurality of softwall mining devices according to the invention connected with a tensioning cable.





FIGS. 6

,


7


, and


8


show cooperative action of a plurality of softwall mining devices working together.





FIG. 9

shows employment of the softwall mining device of the invention in an ore body thicker than the device height.





FIG. 10

shows the use of a plurality of the softwall mining devices of the invention with two parallel main trenches and a perpendicular header trench.





FIG. 11

shows a plurality of softwall mining devices used in an alternative “T” trench configuration.





FIG. 12

shows a locking mechanism according to the present invention.





FIG. 13

shows an isometric view of the softwall mining device of

FIG. 1

, showing the locking mechanism of FIG.


12


.





FIG. 14

shows an alternative locking mechanism according to the present invention.





FIG. 15

shows a linear array of mining devices


10


for illustrating an exemplary mode of operating locking mechanisms according to the present invention.





FIG. 16

shows a channel swab according to the present invention.





FIG. 17

shows an exploded view of a softwall mining device


10


according to the present invention.





FIG. 18

shows a pictorial view of a prior art dragline and sluicing operation for windrow reclaim.





FIG. 19

shows a pictorial view of a dragline and sluicing operation for windrow reclaim according to the present invention.





FIG. 20

shows a pictorial view of an array of longwall mining devices wherein selected devices have a water canon mounted thereon according to the present invention.











DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION




A typical embodiment of the softwall mining equipment of the invention is illustrated in

FIGS. 1 through 4

.

FIG. 1

is an isometric schematic view of a softwall mining device


10


according to the invention. The device


10


consists of a face sluicing chamber


20


partially enclosed within a rear and rear bearing support or shell


22


. The function of the device


10


is to remove ore matrix away from the ore face. This is accomplished by the forward extension of the face sluicing chamber


20


from within the rear bearing support


22


through the actuation of an extension ram


24


. Forward movement is enhanced by the action of a plurality of cutting edge injection nozzles


35


mounted on the face sluicing chamber


20


, as also seen in detail in FIG.


4


A. Elongated slots


41


are provided to movably join the tongue and grooved edges of the face sluicing chamber


20


together with other softwall mining devices.




Rigidly mounted on the rear bearing support


22


, extension guides


26


provide directional thrust control for the device's forward movement. A plurality of rigidly mounted support braces


30


provide vertical strength to the face sluicing chamber


20


. A retractable and extendable rotating ram or guide


38


, pivotally mounted to both the face sluicing chamber


20


and the extension and support assembly


28


, provides vertical movement control. A plurality of rear injectors


31


extend through the rear bearing support


22


to apply fluids into the collapsed overburden.





FIG. 2

shows the softwall mining device


10


in plan view. The extension and retraction of the face sluicing chamber


20


from the rear bearing support


22


is provided by the extension ram


24


attached fixedly to the rear bearing support


22


and pivotally to the extension and support assembly


28


. The extension and support assembly


28


is attached slidingly to both extension guides


26


by means of a plurality of extension and support guide bearing assemblies


25


and directly to the inclined rotating ram


38


.




A plurality of pressurized water supply lines and electrical controls


21


(

FIG. 3

) and water injection control units


34


are attached to face sluicing chamber


20


to provide control of injection fluid pressure and volume. A plurality of pressurized, preferably angularly mounted, injection nozzles


32


fed from each water injection control unit


34


is mounted on the face sluicing chamber


20


to supply fluid injection within the enclosure of the face sluicing chamber


20


.





FIG. 3

is a schematic representation of the cross section of the mining equipment


10


.




The leading edge of a rear bearing support


22


is typically beveled to reduce forward resistance. The inclined rotating guide


38


is fixedly connected to the rear portion of the face sluicing chamber


20


. A rigid support post


37


is rigidly mounted to the floor and roof of the rear bearing support


22


for strengthening the device. A softwall system control line alignment hole


33


is provided in the extension guides


28


. Overlapping side covers


27


are rigidly connected to the rear bearing support


22


to reduce the likelihood of foreign materials entering the device when used in combination with other softwall mining devices.





FIG. 4

shows a more detailed side view of the face sluicing chamber


20


, with enlarged details shown in

FIGS. 4A and 4B

. Pressurized injection fluid is delivered to the plurality of water injection control units


34


through the series of pressurized water supply lines and electrical controls


21


. The water injection control units


34


are mounted on the outside surface of the face sluicing chamber


20


and distribute pressurized injection fluids to the respective pressurized injection nozzles


32


inside the face sluicing chamber


20


. A plurality of nozzles


32


is mounted inside the face sluicing chamber


20


to inject fluids into the ore to break ore from its insitu condition and create a slurry. The face sluicing chamber


20


is preferably machined with a channel inner plate water conduit


42


(

FIG. 4A

) to provide a conduit for injection fluids to travel from the water injection control units


34


to a penetrating edge orifice


40


, where the fluids are injected through multiple cutting-edge injection nozzles


35


. The cutting-edge injection nozzles


35


are mounted rigidly on the leading edge of the face sluicing chamber


20


to inject fluids into the ore matrix to aid in penetration. A face sluicing chamber seal


39


(

FIG. 4B

) provides a seat to prevent external materials from entering the enclosure of the rear bearing support


22


.




The invention is based on the idea of removing the soft ore released at the face by slurrying it with pressurized water, but conventional conveying equipment, such as augers and chain conveyors, could be used as well either to evacuate or promote removal of slurried ore from the sluicing chamber.

FIG. 4C

illustrates such an auger


43


in combination with spray nozzles in the interior of the sluicing chamber


20


.





FIG. 5

shows in perspective view a plurality of softwall mining devices


10


connected with a softwall system control line


29


through the softwall system control line alignment holes


33


. The softwall system control line


29


is secured with a constant tensioning device


64


flexibly attached to the most upstream device in the slurry flow. Adjoining devices


10


are provided with overlapping seals


23


and


36


to minimize leakage of foreign materials into the devices.





FIGS. 6 through 8

refer to the operation of the softwall mining devices


10


of the invention. There are a number of ways the devices of the invention can be operated. The following illustrations are not meant to be exhaustive but rather to illustrate only some of the possible ways and sequences in which they can be used to recover ore slurry material.





FIG. 6

is a schematic representation in plan view of the first step in the operation of the softwall mining devices


10


. The devices are assembled along an ore matrix mining face


56


with full retraction of the face sluicing chambers


20


in preparation for an extension push into the ore matrix mining face


56


against a subsided earthy overburden


54


. Surface compaction equipment


44


could be used on the surface for additional overburden compaction.





FIG. 7

is a schematic representation in plan view of a possible second step in the operation of the devices


10


showing an advance sequence of the face sluicing chamber


20


(illustrated by numerals


61


) against the uniform alignment of adjacent rear bearing supports


22


bearing against the subsided earthy overburden


54


. Prior to advancing into the mining face, the interior portions of the aligned chambers


22


form an open channel through which slurried material can flow. As each chamber is pushed against the mining face with its pressurized injection nozzles


32


operating at fall flow, a portion of the channel is left open for communication with the adjacent chambers, so that the mined ore can flow downstream.




As a result of the extension of the face sluicing chambers


20


into the soft ore matrix, the top leading edges of the chambers penetrate into the ore body and support the overburden, which otherwise would fall in. This support relieves the ore contained within the chambers from the vertical ground pressure at the face. Under these conditions, the forward thrust of the sluicing chambers in combination with the fluidizing action of the pressurized injection fluid produces a volumetric displacement of the soft material in the chambers through the open channel in the downstream chambers and toward the open main trenches. This volumetric displacement and the hydraulic head produced by the injection nozzles enable the slurried ore to flow toward the main trenches even under unfavorable dip conditions of the ore seam. Nevertheless, as would be obvious to one skilled in the art, mining along a down dip is preferred to provide drainage of natural or mining waste water.




Thus, the forward thrust of the sluicing chambers of the invention, utilized in a judiciously selected sequence, produces a pumping action that enables the removal of the ore from the mining face. This approach constitutes a novel concept in mining and is particularly advantageous because it requires the kind of soft, wet and unstable ore conditions that normally render a seam unrecoverable by conventional means.





FIG. 8

is a schematic representation showing a third step in the operation of the softwall mining devices


10


in plan view. In this step, the support units of the rear bearing supports


22


are advanced (i.e., retracted toward the sluicing chambers) in a sequence illustrated, for example, by numerals


63


to show the direction of mining advance, thereby causing subsidence of the earthy overburden


54


behind the devices


10


.




The three steps of the mining cycle illustrated above are repeated to provide uninterrupted mining and flow of ore from the mining face. These steps may be repeated either in the same direction or alternatively in opposite directions, if open main trenches are provided at both ends of the face. If necessary in order to create an open channel at the face, all chambers may need to be retracted a short distance from the face before a new push cycle is begun. For very long mining faces, the cycling of the steps will preferably occur in batches among groups of devices feeding multiple main entries at various points along the mining face such that all three steps are substantially contemporaneous at different positions along the face to secure its uniform advancement.





FIG. 9

shows a multiple lift mining sequence


68


with a softwall mining device


10


or a set of devices in an ore body thicker than the device's height. The same device


10


or set of devices can be used to first mine the top layer of the ore seam and then relocated to mine additional lower layers as desired, the thickness of each layer being substantially equal to the height of the mining device. Alternatively, multiple devices or sets of devices may be arranged as seen in

FIG. 9

to sequentially mine each layer downward from the top of the seam. This alternative could be carried out in alternative fashion by operating all sets of mining devices at the same time maintaining the relative position illustrated in the figure. Subsidence of the original overburden surface


50


will occur in stair-step fashion possibly producing a subsided surface


52


as the ore matrix


57


is removed.





FIG. 10

illustrates the use of a plurality of softwall mining devices


10


with two parallel main trenches


60


and a perpendicular header trench


66


extending the fill distance of the panel width


59


. A plurality of adjacent softwall mining devices


10


progresses more or less parallel to the ore matrix mining face


56


. A closed end


58


in a face sluicing chamber


20


in the middle of the face divides the header trench


66


forcing the slurried ore to follow the flow directions


65


toward the mains


60


, where slurried ore is collected by trench-gate slurry handling equipment


62


placed at each main trench's end for transport and processing.





FIG. 11

shows the use of a plurality of softwall mining devices


10


using an alternative “T” trench configuration with two header trenches


66


feeding into a single main trench


60


excavated during the mine development phase.




In one aspect of the invention, the rear bearing supports


22


are anchored to support advancement of the face sluicing chambers


20


by the weight of the overburden. In another aspect of the invention described below, the mining devices themselves provide some or all of this anchoring function and the devices may be used, for example, in surface mining, windrow reclaim, or other circumstances in which overburden is not present. In this latter aspect, individual devices


10


may be arrayed as shown in FIG.


10


and locked together to provide a relatively large mass to support the advancement of one or more face sluicing chambers.




More particularly, the rear bearing supports


22


of such an array of the devices


10


may be locked together and the face sluicing chambers


20


of the devices


10


may be separately locked together. This provides for a half-cycle of operation of the devices


10


wherein a relatively large number of the rear bearing supports


22


may function as an anchor for advancing, into the mining face, a relatively small number of the face sluicing chambers


20


, and another half-cycle of operation wherein the face sluicing chambers are locked together to anchor the advancement toward the mining face of the rear bearing supports.





FIG. 12

shows a locking mechanism


70


according to the present invention, for locking together the face sluicing chambers


20


and the rear bearing supports


22


of adjacent devices


10




a


and


10




b


. A slidable pin


71




a


is provided on a side


72




a


of the face sluicing chamber and another similar pin


71




b


is provided on a side


73




a


of the rear bearing


20


support of one of the devices


10




a


. An adjacent device


10




b


includes complementary recesses


74




a


,


74




b


to receive the respective pins, which locks the devices


10


together. Preferably, the pin is tapered to align the devices together at the same time. Each device


10


may include pins on one side and complementary recesses on the other.





FIG. 13

shows a hydraulically powered piston and cylinder assembly


100


for actuating the pins


71




a


and


71




b


. The assembly


100


of

FIG. 13

is double-acting and also actuates pins


75




a


and


75




b


extending from the opposite sides


72




b


and


73




b


of the face sluicing chamber


20


and rear bearing support


22


, respectively. Therefore, with the cylinder assembly


100


, only half of the devices


10


include pins and the assembly


100


, while the other half of the devices include complementary recesses and are spaced therebetween. However, this convenience is not essential to the invention. For example, a single acting assembly in each of the mining devices


10


may be employed.




The cylinder assembly


100


is preferably controlled hydraulically as discussed more fully below. This provides for a number of advantages, including eliminating the need for electricity in an often wet environment.




The devices


10


are preferably tied together through the control line


29


with the aid of the tensioning device


64


(see FIG.


5


). This has been found to be important when using the piston and cylinder assembly


100


, the control line resisting the tendency for the pin


71


or


75


of one device


10




a


to push the adjacent device


10




b


away.





FIG. 14

shows an alternative locking mechanism


80


. A cam or hook


82


is pivotally mounted to one of the units


10




a


, the cam being preferably driven by a hydraulically powered and controlled arm


84


. The cam has a tooth


86


that is engageable with an aperture


88


in an adjacent device


10




b


. The cam locking mechanism has the advantage that it positively pulls the adjacent devices


10




a


and


10




b


together. Like the pin


71


and/or


75


of the aforedescribed piston and cylinder assembly, the tooth


86


is preferably tapered to provide for aligning the adjacent devices at the same time.




Locking the rear bearing supports


22


of a predetermined number of the devices


10


provides the combined weight of the locked assembly for anchoring the (forward) advancement of the face sluicing chambers


20


of a subset of these devices. The face sluicing chambers are advanced into the mining face by extending the extension ram


24


.




A minimum number of the devices


10


can be determined for anchoring the simultaneous advancement of a desired number of face sluicing chambers. For example, a minimum number “Nrb” of the devices may be calculated to provide the mass sufficient to resist, by friction and inertia, the forces applied to a single face sluicing chamber


20


as it advances into the mining face. These forces result primarily from the resistance of the mining face to advancement of the leading edges


19


of the face sluicing chamber


20


, and reaction to the flow through the nozzles


32


,


35


and to the flow of slurry through the channel that is formed by the interior of the face sluicing chamber


20


. Alternative to calculating the number of rear bearing supports that must be locked together, this number may be determined by trial and error. As will be readily appreciated, more of the rear bearing supports


22


may be locked together than is minimally required, and a number of the face sluicing chambers


20


may be advanced at the same time provided there is a corresponding increase in the number of rear bearing supports that are locked together.




In the first half-cycle of operation of the devices


10


, the face sluicing chambers


20


of a predetermined number of devices having their rear bearing supports locked together as aforedescribed are advanced or moved forwardly, into the mining face, either one at a time or in relatively small groups (hereinafter “sequentially”). The devices


10


are typically, though not necessarily organized in a linear array such as that shown in

FIG. 10

, and the devices are typically, though not necessarily, operated in order to provide for the peristaltic pumping discussed above.




When a desired number of adjacent face sluicing chambers


20


have been advanced, the second half-cycle of operation is commenced by locking the face sluicing chambers together to provide an anchor for advancing the rear bearing supports


22


of the devices


10


.




Locking the face sluicing chambers


20


of a predetermined number of the devices


10


provides weight for anchoring the advancement of the rear bearing supports


22


of a subset of these devices. The rear bearing supports are advanced toward the face sluicing chambers by contracting the extension ram


24


.




A minimum number of the devices


10


can be determined for anchoring the simultaneous advancement of a desired number of rear bearing supports. For example, a minimum number “Nrb” of the devices may be calculated to provide the mass sufficient to resist, by friction and inertia, the forces applied to a single rear bearing support


22


as it advances toward the face sluicing chamber


20


. These forces result primarily from the resistance of the earth underneath and above the rear bearing support. Alternative to calculating the number of face sluicing chambers that must be locked together, this number may be determined by trial and error. As will be readily appreciated, more of the face sluicing chambers


20


may be locked together than is minimally required, and a number of the rear bearing supports


22


may be advanced at the same time provided there is a corresponding increase in the number of face sluicing chambers that are locked together.




In the second half-cycle of operation of the devices


10


, the rear bearing supports


22


of a predetermined number of devices having their face sluicing chambers locked together as aforedescribed are advanced toward the respective face sluicing chambers, either one at a time or in relatively small groups, i.e., sequentially. Preferably, advancement of the rear bearing supports is by retraction of the extension arm


24


; however, other mechanisms may be employed to advance the rear bearing supports without departing from the principles of the invention. The devices


10


are typically, though not necessarily, organized in a linear array such as that shown in

FIG. 10

, and the devices are typically, though not necessarily, operated in order. When a desired number of rear bearing supports


22


have been advanced, the first half-cycle described above may be repeated.




As mentioned above, the locking mechanisms are preferably operated hydraulically. Hydraulic circuits for this purpose are provided for each of the devices


10


which include a hydraulically operated portion of a locking mechanism, and these circuits are preferably plumnbed in series following the sequence in which such devices are intended to be operated. One specific example of the operation of a circuit according to this principle is given below. As will be readily appreciated by the person of ordinary skill, there are many different ways to realize a hydraulic circuit having the below described mode of operation.





FIG. 15

shows three devices


10


, i.e.,


10




a


,


10




b


and


10




c


, in a linear array. In this example, devices


10




a


and


10




b


have pins


71




a


and


71




b


for each respective face sluicing chamber and devices


10




b


and


10




c


have corresponding complementary recesses


72




b


and


72




c


. Also, devices


10




b


and


10




c


have pins


710




b


and


710




c


for each respective rear bearing support, and devices


10




a


and


10




b


have corresponding complementary recesses


720




a


and


720




b


. Accordingly, all three devices have a hydraulic circuit, and these are plumbed in series.




Prior to the first half cycle, the rear bearing supports for all of the devices are locked together by extension of the pins


710




a-c


into the recesses


720




a-b


. This provides alignment and anchoring support for the movements that follow. The face sluicing chambers


20




a-




20




c


are unlocked from one another, by retraction of the pins


71




a-b


from the recesses


72




a-b.






Commencing the first half cycle, the extension ram


24




a


of the device


10




a


extends to advance the corresponding face sluicing chamber


20




a


. When the ram


24




a


reaches full extension, a pressure or position (hereinafter “position”) activated valve


90




a


senses this condition and applies fluid to the ram


24




b


of the device


10




b


. This extends the ram


24




b


to advance the corresponding face sluicing chamber


20




b.






When the ram


24




b


reaches full extension, a position activated valve


90




b


senses this condition and applies fluid to the ram


24




c


of the device


10




c


and to the piston


71




a


. This extends the ram


24




c


to advance the corresponding face sluicing chamber


20




c


, and extends the pin


71




a


into the recess


72




b


, locking the face sluicing chambers


20




a


and


20




b


together.




When the ram


24




c


reaches full extension, a position activated valve


90




c


senses this condition and applies fluid to the pin


71




b


. This extends the pin


71




b


into the recess


72




c


, locking all of the face sluicing chambers together and completing the first half cycle of operation and providing anchoring support for the movements that follow.




Commencing the second half cycle, with the face sluicing chambers of all of the devices locked together, the valve


90




c


applies fluid to the pin


710




c


and to the ram


24




c


. The pin


710




c


retracts to unlock the rear bearing support


22




c


from the rear bearing supports


22




a


and


22




b


, and the ram


24




c


retracts to advance the rear bearing support


22




c


toward the face sluicing chamber


20




c.






When the ram


24




c


reaches full retraction, a position activated valve (preferably the valve


90




c


) applies fluid to the pin


710




b


and the ram


24




b


. The pin


710




b


retracts to unlock the rear bearing support


22




b


from the rear bearing support


22




a


, and the ram


24




b


retracts to advance the rear bearing support


22




b


toward the face sluicing chamber


20




b.






When the ram


24




b


reaches full retraction, a position activated valve (preferably the valve


90




b


) applies fluid to the pin


710




c


and the ram


24




a


. The pin


710




c


extends into the recess


720




b


to lock the rear bearing supports


22




b


and


22




c


together and the ram


24




a


retracts to advance the rear bearing support


22




a


toward the face sluicing chamber


20




a.






When the ram


24




a


reaches full retraction, a position activated valve (preferably the valve


90




a


) applies fluid to the pin


710




b


, which extends into the recess


720




a


to lock all of the rear bearing supports together, completing the second half cycle.




With the second half cycle completed, the first half cycle is ready to be repeated. Though a specific example of control of the devices


10


has been provided, many alternative modes of operation of the devices


10


according to the general principles of the invention are possible and will be readily apparent to those of ordinary skill in light of the example. For example, the double acting pins discussed above may be employed, and separately controlled electric or hydraulic circuits may be provided for operating the extension ram


24


and the pins.




Preferably, at the same time that the face sluicing chambers


20


are advanced by extending the corresponding extension rams


24


of the devices


10


, the hydraulic circuit provides for injecting water through the injection nozzles


32


(

FIG. 4

) of the same device


10


. As the sluicing chambers of adjacent devices are successively moved, the simultaneous injection of water provides for pumping action on the slurry that results. In that regard, the peristaltic pumping action provided by sequentially operating adjacent devices


10


may commence in the center of the array and move outwardly toward one or both sides, to decrease the pumping distance.




Returning to

FIG. 13

, a semi-cylindrical channel portion


94


is formed between the face sluicing chamber


20


of a single device


10


and a mining face


96


. An array of the devices produces a channel


99


(

FIG. 5

) that comprises the sum of the channel portions of all of the devices. In

FIG. 13

, where only one mining device is shown, the channel is defined by the channel portion


94


. The channel carries off the slurry that is produced at the mining face. The channel is preferably lined with a flexible lining, a portion of which corresponds to the device


10


in

FIG. 13

, indicated as


102


. Preferably, the lining is substantially continuous across at least a plurality of the devices and, more preferably, it is continuous across all of the devices to prevent slurry and mining fluids from entering the rear bearing supports through spaces between the adjacent devices. The lining is flexible to permit relative advancement of the face sluicing chambers


20


of adjacent devices without rupture. The lining smooths the channel during the time that adjacent face sluicing chambers in the array are displaced with respect to one another.





FIG. 16

shows a swab


101


for use in the channel


99


. The swab comprises a pair of bi-directional winches


104




a


,


104




b


driving a flexible line


106


through the channel. Attached to the line


106


is a clearing member


108


. The face sluicing chambers have a predetermined stroke, provided by the extension ram


24


. The stroke may be selected according to conditions to provide a desired pumping action and speed as will readily be appreciated by the person of ordinary skill. The swab


101


has a width “w” that is preferably about as wide as this stroke and a height “h” that is about twice this width for a face sluicing chamber having a height “h


fsc


” (see FIG.


13


). The swab is thereby adapted to bore a relatively small conduit through the channel. However, the swab


101


may have any other desired dimensions relative to the size of the channel portion


94


(

FIG. 13

) without departing from the principles of the invention.




The swab may be employed for clearing obstructions in the channel


99


and can be run forwardly or backwardly through the channel for this purpose. Use of the swab may also be coordinated with the movements of the devices


10


to provide a conduit for slurry flow in case the channel should fill with mud. For example, if a linear array of the devices


10


is arranged to advance sequentially into the mine face from left to right, the swab may be positioned to the left of the first device in the sequence and be moved from left to right in unison, lagging behing the movement of the adjacent face sluicing chamber


20


. On the next pass, the conduit formed by movement of the swab


101


ensures that slurry will be able to flow.




The swab also provides some degree of backflow resistance, to direct the flow of slurry in the preferred direction. In addition,

FIG. 17

shows a side cover


104


for use with a selected one of the devices to completely obstruct the channel at that device and prevent flow past the device in either direction.





FIG. 17

shows an exploded view of one of the devices


10


. A plate


110


is applied to one or both sides of face sluicing chamber


20


to provide structural support for supporting overburden. The plate(s)


110


may be used to replace the structural supports


30


(

FIG. 1

) and provide the advantage of leaving the channel


100


clear of structural obstruction. The supports


30


have in the past included cutting edges to permit the supports to penetrate the mining face, therefore providing for greater penetration by the face sluicing chamber. Eliminating the struts removes the need for these additional cutting edges. Therefore, the plate


110


provides that the force applied by the face sluicing chamber against the mining face is distributed over a smaller number of cutting edges


120


, increasing the cutting or penetrating pressure.




A portion


106


of a second flexible lining that covers back portions


108


of the rear bearing supports


22


protects the back portions from entry of mud and other debris into the rear bearing supports. Like the flexible lining of which the portion


102


corresponding to the mining device


10


is shown, the flexible lining of which the portion


106


is shown is sufficiently flexible to permit relative movement of adjacent mining devices without rupture.





FIG. 18

shows a pictorial view of a prior art dragline and sluicing operation for windrow reclaim. The example is illustrative of a problem that is present in surface mining generally. A dragline excavator


130


excavates a mining pit


132


. The dragline generally progresses in the direction shown by the arrow “A.” A sluicing pit


134


is provided adjacent the mining pit. As the dragline removes earth from the mining pit, it deposits the earth into the sluicing pit (in the direction of the arrow “B”). A water canon or other water delivery system


136


is provided at the sluicing pit to turn the excavated earth into a slurry so that the earth may be pumped away to a point of collection (along “C”).




One problem with this prior art method is that the sluicing pit is often a bottleneck in the flow of earth from the pit to the ultimate point of pumping of the slurry. If the pit is full, the dragline must wait to deposit more excavated earth. Another problem with the method is that the sluicing pit becomes out of reach of the dragline as the dragline travels along the direction “A” and the length “L” of the mining pit increases as a result. To solve this problem, the pit is periodically reconstructed to move with the dragline; however, this is costly and time consuming.





FIG. 19

shows a pictorial view of a dragline and sluicing operation for windrow reclaim according to the present invention. The dragline


130


moves the excavated earth (along the direction of the arrow “B”) to the side of the mining pit as the dragline travels in the direction of the arrow “A”, creating a pile


140


of excavated earth. An array


138


of softwall mining devices


10


is provided to transform the pile into slurry and to move the slurry to a slurry collection and pumping station


142


for pumping the slurry to a point of collection (along “C”). An outstanding advantage of the method is that it decouples the excavation from the creation and pumping of the slurry, so that the latter cannot slow the rate of the former. The array


138


may be operated simultaneously with operation of the dragline, or it may be operated at any other time without impacting the operation of the dragline.




A method according to the invention for windrow reclaim having been described, it should be understood that there is no intention to limit the invention to windrow reclaim. Rather, the method may be employed in any desired surface or other mining application.




Returning to

FIG. 17

, for sub-surface mining a top cover


112


(and bottom cover


114


) are included in the rear bearing support to protect the rear bearing support and to provide structural rigidity and strength. However, for surface mining, windrow reclaim and similar mining operations, at least the top cover may be eliminated or employed as a foundation for an additional water canon or water nozzle.





FIG. 20

shows selected mining devices


10


provided with a water canon or other water delivery system


136


, preferably on the rear bearing supports


22


and more particularly on or in the location of the top cover


112


, which may be omitted. The water canon may be used, for example, in the windrow reclaim operation discussed immediately above, or in other surface mining operations. While the water canon is not essential, the present inventors have recognized that the mining devices


10


provide an advantageous platform for the water canon


136


, which may be used to assist the face sluicing chambers


20


of the mining devices


10


to transform the windrow to slurry.




It should be appreciated that an outstanding advantage of the softwall mining devices


10


results from providing for controlling the amount of moisture added to excavated earth or ore for forming a slurry. The control afforded by the devices


10


when used for sub-surface mining provides for a slurry of phosphate bearing clay, for example, at 35 to 40% solids content, which represents about a 5-20% improvement over the prior art. This results from sealing the mining face with the face sluicing chambers


20


, preventing the entry of sub-surface water. For windrow reclaim, the ore is taken out of the pit where it would otherwise be mixed with water, and the water drains back into the pit, leaving the ore relatively dry. Then, the water canon may be employed to add back just the amount of water necessary to flow the ore from the site.




Various changes in the details, steps and materials that have been described may be made by those skilled in the art within the principles and scope of the invention herein illustrated and defined in the appended claims. Therefore, while the present invention has been shown and described in what is believed to be the most practical and preferred embodiments, it is recognized that departures can be made therefrom within the scope of the invention, which is therefore not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent apparatus and methods.



Claims
  • 1. A method for mining comprising the steps of providing a plurality of mining devices each comprising a supporting portion, an earth moving portion, and a coupling mechanism operably providing for increasing and decreasing the separation therebetween and thereby for advancing the earth moving portion with respect to the supporting portion into a mining face and the supporting portion toward the earth moving portion, selecting a first mining device of said plurality of mining devices for advancement, operating a locking mechanism that releasably locks the supporting portion of said first mining device to supporting portions of other of said plurality of mining devices to which the supporting portion of said first mining device was not previously locked by said mechanism to anchor said advancement, and operating the coupling mechanism of said first mining device for advancing the earth moving portion of said first mining device ahead of the respective supporting portion.
  • 2. The method of claim 1, wherein said locking mechanism comprises at least one of a locking pin and a complementary aperture adapted to receive the locking pin of an adjacent one of said plurality of mining devices, wherein the method further comprises selecting one of said plurality of mining devices that is adjacent said first mining device, and wherein said step of operating said locking mechanism includes extending the locking pin of one of said mining devices into the aperture of the selected said one of said plurality of mining devices that is adjacent said first mining device.
  • 3. The method of claim 1, wherein said locking mechanism comprises at least one of a pivotally mounted hook and a complementary aperture adapted to receive the hook of an adjacent one of said plurality of mining devices, wherein the method further comprises selecting one of said plurality of mining devices that is adjacent said first mining device, and wherein said step of operating said locking mechanism includes pivoting the hook of one of the mining devices into the aperture of the selected said one of said plurality of mining devices that is adjacent said first mining device.
  • 4. The method of claim 1, wherein said locking mechanism includes, in about half of said plurality of mining devices, a movable member and, in the about the other half of said plurality of mining devices, an aperture for receiving at least a portion of the movable member of an adjacent one of said plurality of mining devices, wherein the method further comprises selecting one of said plurality of mining devices that is adjacent said first mining device, and wherin said step of operating said locking mechanism includes inserting at least a portion of the movable member of one of the said plurality of mining devices into said at least a portion of the aperture of the selected said one of said plurality of mining devices that is adjacent said first mining device.
  • 5. The method of claim 1, further comprising selecting a second of said plurality of mining devices for advancement and sequentially operating the coupling mechanism of said second of said plurality of mining devices for advancing the earth moving portion of said second of said plurality of mining devices ahead of the respective supporting portion.
  • 6. The method of claim 5, wherein said step of selecting said second of said plurality of mining devices comprises selecting one of said plurality of mining devices that is adjacent to said first mining device.
  • 7. The method of claim 6, further comprising selecting a third of said plurality of mining devices for advancement and sequentially operating the coupling mechanism of said third of said plurality of mining devices for advancing the earth moving portion of said third of said plurality of mining devices ahead of the respective supporting portion.
  • 8. The method of claim 7, wherein said step of selecting said third of said plurality of mining devices comprises selecting one of said plurality of mining devices that is adjacent said second of said plurality of mining devices.
  • 9. The method of claim 7, wherein said step of selecting said third of said plurality of mining devices comprises selecting a remaining one of said plurality of mining devices that is adjacent said second of said plurality of mining devices.
  • 10. The method of claim 5, wherein the respective earth moving portions of said first and second of said plurality of mining devices are advanced with respect to the respective supporting portions, the method further comprising releasably locking the respective earth moving portions of said first and second of said plurality of mining devices together, selecting one of said first and second of said plurality of mining devices, unlocking the supporting portion of said selected one of said first and second of said plurality of mining devices, and operating the coupling mechanism of said selected one of said first and second of said plurality of mining devices to advance the supporting portion thereof toward the respective earth moving portion.
  • 11. The method of claim 10, further comprising unlocking the supporting portion of the other of said first and second of said plurality of mining devices, and sequentially operating the coupling mechanism of said other of said first and second of said plurality of mining devices to advance the supporting portion thereof toward the respective earth moving portion.
  • 12. A method for mining comprising the steps of providing a plurality of mining devices each comprising a supporting portion, an earth moving portion, and a coupling mechanism operably providing for increasing and decreasing the separation therebetween and thereby for advancing the earth moving portion with respect to the supporting portion into a mining face and the supporting portion toward the earth moving portion, selecting a first of said plurality of mining devices for advancement, operating a locking mechanism that releasable locks the earth moving portion of said first mining device to earth moving portions of other of said plurality of mining devices to which the earth moving portion of said first mining device was not previously locked by said mechanism to anchor said advancement, and operating the coupling mechanism of said first mining device for advancing the supporting portion of said first mining device toward the respective earth moving portion.
  • 13. The method of claim 12, further comprising selecting a second one of said plurality of mining devices for advancement and sequentially operating the coupling mechanism of said second of said plurality of mining devices for advancing the supporting portion of said second of said plurality of mining devices toward the respective earth moving portion.
  • 14. The method of claim 13, wherein said step of selecting said second of said plurality of mining devices comprises selecting one of said plurality of mining devices that is adjacent to said first of said plurality of mining devices.
  • 15. The method of claim 13, further comprising selecting a third of said plurality of mining devices for advancement and sequentially operating the coupling mechanism of said third of said plurality of mining devices for advancing the supporting portion of said third of said plurality of mining devices ahead of the respective earth moving portions.
  • 16. The method of claim 15, wherein said step of selecting said third of said plurality of mining devices comprises selecting one of said plurality of mining devices that is adjacent said second of said plurality of mining devices.
  • 17. The method of claim 15, wherein said step of selecting said third of said plurality of mining devices comprises selecting a remaining one of said plurality of mining devices that is adjacent said second of said plurality of mining devices.
  • 18. The method of claim 13, wherein the respective supporting portions of said first and second of said plurality of mining devices are advanced with respect to the respective earth moving portions, the method further comprising releasably locking the respective supporting portions of said first and second of said plurality of mining devices together, selecting one of said first and second of said plurality of mining devices, unlocking the earth moving portion of the selected one of said first and second of said plurality of mining devices, and operating the coupling mechanism of said selected one of said first and second of said plurality of mining devices to advance the earth moving portion thereof ahead of the respective supporting portion.
  • 19. The method of claim 18, further comprising unlocking the earth moving portion of the other of said first and second of said plurality of mining devices, and sequentially operating the coupling mechanism of said other of said first and second of said plurality of mining devices to advance the earth moving portion thereof ahead of the respective supporting portion.
RELATED APPLICATIONS

This application is a continuation-in-part of Ser. No. 09/287,885, filed Apr. 7, 1999, now U.S. Pat. No. 6,086,159, which is a continuation-in-part of Ser. No. 08/851,680, filed May 6, 1997, now abandoned.

US Referenced Citations (4)
Number Name Date Kind
2716025 Malloy et al. Aug 1955 A
4095845 Paurat Jun 1978 A
4217067 Lagodka et al. Aug 1980 A
6267191 Hettinger Jul 2001 B1
Continuation in Parts (2)
Number Date Country
Parent 09/287885 Apr 1999 US
Child 09/609568 US
Parent 08/851680 May 1997 US
Child 09/287885 US