U.S. patent number RE29,021 [Application Number 05/595,506] was granted by the patent office on 1976-11-02 for underground mining system.
This patent grant is currently assigned to Marcona Corporation. Invention is credited to William R. Archibald, John J. Gilbert.
United States Patent |
RE29,021 |
Archibald , et al. |
November 2, 1976 |
Underground mining system
Abstract
Hydraulic underground mining system adapted to operate through a
small diameter well bore and into a subterranean body and including
a mining capsule carried on the lower end of an elongate support
structure. The mining capsule includes a liquid jet nozzle at its
upper end for forming a laterally directed jet stream to impact
material in the ore body and to pulp the same into a slurry. An
orifice having a grate for preventing entry of excessively large
material is positioned below the jet so that freshly pulped slurry
flows into the orifice, the latter being connected to an elongate
positive displacement pump mounted below the orifice. Suitable
hydraulic power means are provided for operating the pump and for
progressively moving the jet stream .[. .]. .Iadd.through
.Iaddend.at least a portion of an arc. Fixed liquid jets are also
provided at the pump inlet for flushing and priming and to the
lowermost portion of the capsule and to facilitate movement of the
apparatus in the well bore.
Inventors: |
Archibald; William R. (Tiburon,
CA), Gilbert; John J. (San Francisco, CA) |
Assignee: |
Marcona Corporation (San
Francisco, CA)
|
Family
ID: |
26984320 |
Appl.
No.: |
05/595,506 |
Filed: |
July 14, 1975 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
324168 |
Jan 16, 1973 |
03797590 |
Mar 19, 1974 |
|
|
Current U.S.
Class: |
175/213; 175/424;
299/64; 175/67; 299/17 |
Current CPC
Class: |
E21B
7/18 (20130101); E21B 21/00 (20130101); E21B
43/29 (20130101) |
Current International
Class: |
E21B
43/00 (20060101); E21B 43/29 (20060101); E21B
7/18 (20060101); E21B 21/00 (20060101); E21C
045/00 () |
Field of
Search: |
;299/17,18,64
;175/67,213,217,422 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Purser; Ernest R.
Attorney, Agent or Firm: Flehr, Hohbach, Test, Albritton
& Herbert
Claims
We claim:
1. Hydraulic mining apparatus for operating through a well bore
drilled into a subterranean body to be mined, comprising an
elongate support structure, means for suspending said support
structure in said well bore, a mining capsule carried on the lower
end of said support structure, said mining capsule comprising means
at its upper end for hydraulically mining said ore body including
jet means for developing a laterally directed liquid jet stream to
impact material in said body and pulp the same into a slurry, means
for moving said jet means back and forth through at least a partial
arc, means forming a discharge orifice positioned below said jet
and including grate means for preventing excessively large chunks
of material from entering said orifice, means forming an elongate
positive displacement pump positioned below said orifice and
connected thereto so that pulped slurry flows through said grate
and orifice and into pump under gravity, hydraulic power means for
driving said pump, piping means for connecting said hydraulic power
means to the ground level end of said apparatus, and a slurry
discharge line connected to the outlet end of said pump, said
discharge piping extending upwardly to the ground level end of said
apparatus and through said support structure.
2. Hydraulic mining apparatus as in claim 1 in which said positive
displacement pump is of a linear type including means for forming a
succession of cavities linearly arranged and progressively moveable
in either direction of said pump whereby said pump may be reversed
or operated in a positive sense to provide for flushing and
start-up pumping.
3. Apparatus as in claim 2 further including a flushing jet
connected to the inlet end of said pump for flooding the same
during start-up and for controlling the liquid content of slurry
during operation.
4. Hydraulic mining apparatus as in claim 1 further including a
cylindrical shroud extending the length of said apparatus and
serving to stabilize the well bore in which said apparatus is
positioned.
5. Hydraulic mining apparatus as in claim 1 in which said pump and
the .[.motor.]. .Iadd.power .Iaddend.means for operating said pump
and for moving said jet means are located in the lowermost portion
of said capsule and beneath said orifice.
6. Hydraulic mining apparatus as in claim 1 including a flushing
jet positioned at the lowermost end of said apparatus and directed
downwardly therefrom for facilitating movement of said apparatus in
said well bore. .Iadd. 7. Mining apparatus for operating through a
subterranean bore extending from the exterior surface of the ground
and into a subterranean body of friable material to be mined,
comprising support means, a mining assembly carried by the support
means within the bore and in the region of the body, the mining
assembly being a compact structural unit dimensioned with respect
to the dimensions of the bore to enable the same to be transported
into the bore to a desired position within the body, the assembly
unit including jet means for discharging a liquid jet stream into
the body to impact the material in the body and pulp the same into
a slurry, means for moving the jet means through at least a partial
arc whereby a cavity is progressively formed in the body from which
the slurry flows toward the assembly unit, the assembly unit having
an opening located below the zone of operation of the jet means and
disposed to receive the slurry flow, a grate disposed in the
opening for preventing excessively large chunks of material from
entering said opening, an elongated mechanical pump forming a part
of the assembly unit and having an inlet at one end of the same and
a discharge outlet at the other end, the inlet being connected to
receive slurry flowing through the opening and the grate, the pump
being in general alignment with the bore, means for driving the
pump, means including piping connected to the outlet of the pump
and extending through the bore from one end of the unit to the
ground surface for the discharge of slurry, and means including
piping extending through the bore from the ground surface for
delivering liquid under pressure to the jet means. .Iaddend. .Iadd.
8. Mining apparatus as in claim 7 in which the bore extends
downwardly and the assembly is an elongated unit that includes the
jet means, the grate, and the pump, and means for supplying driving
power to the pump from the surface of the well. .Iaddend. .Iadd. 9.
Mining apparatus for operating through a well bore extending down
into a subterranean body of friable material to be mined,
comprising a support means, a mining assembly carried by said
support means within the well bore, the mining assembly being a
compact structural unit dimensioned with respect to the dimensions
of the bore to enable the same to be transposed into the bore to a
desired position within the body, said mining assembly unit
comprising means for hydraulically mining said ore body including
jet means for developing a laterally directed liquid jet stream to
impact material in said body and pulp the same into a slurry, means
for moving said jet means through at least a partial arc whereby a
cavity is progressively formed in the body from which the slurry
flows toward the assembly unit, means forming a slurry receiving
opening positioned below the zone of operation of the jet means and
including grate means for preventing excessivley large chunks of
material from entering said opening, an elongated mechanically
driven pump forming a part of the assembly unit and having an inlet
at one end of the same and a discharge outlet at the other end, the
inlet being connected to the opening so that pumped slurry flows
through said grate and opening and into the intake at the lower end
of said pump, the pump being in general alignment with the bore,
means for supplying driving power to the pump from the upper ground
surface, a slurry discharge line connected to the outlet of the
pump, said discharge line extending upwardly through the bore to
the ground level, and means including piping extending through the
bore from the ground surface for deliverying liquid under pressure
to the jet means. .Iaddend. .Iadd. 10. Mining apparatus as in claim
9 in which the assembly is in the form of an elongated unit which
includes the jet means, the slurry receiving opening and grate
means, and the pump, all disposed along the length of the unit.
.Iaddend.
Description
BACKGROUND OF THE INVENTION
This invention relates to underground mining. More particularly
this invention relates to a hydraulic underground mining system in
which mining at significant depths is accomplished by means such
that a hydraulic mining fluid is introduced as a jet within a
subterranean ore body to form a slurry in which form the ore is
removed and brought to the surface.
Subterranean mining of ore bodies by hydraulic mining through well
bores has been known, as for example, as set forth in the patent to
Aston U.S. Pat. No. 2,518,591. Such mining takes place by
slurrification of material in a subterranean mineral deposit and
removal of the slurrified material. In the past, jet pumps have
been used to lift the slurry out of the mining area. However, the
use of jet pumps limits the lift height to .[.valves.].
.Iadd.values .Iaddend.which are inadequate for many ore bodies. In
addition, jet pumps tend to require large quantities of motive
water which results in a very dilute slurry having too low a solids
content. This results in consumption of excessive energy and
water.
Pressure lift systems have also been proposed, as for example, in
the U.S. Pat. No. 3,439,953 to Pfefferle. In such systems, a well
bore casing is sealed to the surrounding ground and sufficient
pressure is then applied in the subterranean deposit, i.e.,
internally of the ore body to expel slurrified contents through a
conduit to the surface. Such a pressure system is relatively
expensive to operate due to weight and power required to make up
for seepage loss caused by the porosity of the region surrounding
the mined area and also due to the difficulty of maintaining a
casing seal under pressures adequate to drive the slurrified
material to the surface. Such systems are also subject to casing
failure or to failure of the seal. Where the casing or seal has
failed, mining through that bore usually becomes impractical and if
the overburden subsides upon loss of pressure the entire rig may be
unrecoverable. In addition, most prior art systems have required
large well bores, often in excess of 2 feet. The cost of drilling
large well bores is often too high to permit economic recovery of
even shallow ore deposits. There is therefore, a need for a new and
improved subterranean mining method and apparatus.
SUMMARY OF THE INVENTION AND OBJECTS
In general, it is an object of the present invention to provide a
new and improved hydraulic underground mining system which will
overcome the above limitations and disadvantages. It is a further
general object of the invention to provide an underground mining
system of the above character capable of efficient mining and
removal of the mined material as a high solids content slurry in
which the water utilized in the mining operation is also used as
the suspending liquid for the slurry.
A further object of the invention is to provide an underground
mining system of the above character capable of operation through a
small diameter well bore at depths significantly greater than one
hundred feet.
A further object of the invention is to provide a hydraulic
underground mining system of the above character in which there is
no requirement for a seal between the well bore casing and the
lateral supporting earth.
A further object of the invention is to provide an underground
mining system of the above character which eliminates the use of
pressure for slurry removal and which has inherently high
efficiency and economy of operation.
A further object of the invention is to provide a particularly
novel underground mining apparatus.
The foregoing objects are achieved by providing an underground
mining system adapted to operate through a well bore drilled into a
subterranean body to be mined. The well bore is small in diameter
and is drilled completely through the portion of the body to be
mined and a further substantial distance below it to provide for
insertion of the mining apparatus as will be described. The mining
apparatus includes an elongate support structure having a diameter
slightly smaller than the well bore and including a mining capsule
carried at its lower end. The upper end is suspended in a suitable
manner at the ground level as by being carried on a truck mounted
drill rig or on a support flange. The mining capsule includes means
at its upper end for hydraulically mining into the ore body
including jet means for developing a laterally directed liquid jet
stream to impact material in the body and pulp the same into a
slurry. Below the jet means a discharge sump is formed including a
grate for preventing excessively large chunks of material from
entering the sump. Means is also provided for moving the jet back
and forth through at least a partial arc so that the jet
progressively impinges upon material to pulp the same. The material
thereafter flows backwardly toward the jet and into the discharge
sump. An elongate positive displacement pump is positioned in the
sump and has an inlet connected thereto so that pulp slurry flows
through the grate and into the pump under gravity. Hydraulic power
means drive the pump and suitable piping is provided for supplying
hydraulic motive power to a pump motor and to the means for moving
the jet nozzle. Additional piping is provided for supplying liquid
under high pressure to the jet nozzle and for serving as a slurry
discharge line.
These and other objects and features of the invention will become
apparent from the following description thereof when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 is a cross-sectional view partly broken away and partly in
schematic form of an underground mining system constructed in
accordance with the present invention.
FIGS. 2A and 2B are isometric views of the mining capsule portion
of the mining system of FIG. 1.
FIGS. 3A, 3B, 3C and 3D are enlarged elevational views of the
mining capsule of FIGS. 2.
FIG. 4 is a cross-sectional view taken along lines 4--4 of FIG.
3B.
FIG. 5 is a cross-sectional view taken along lines 5--5 of FIG.
3B.
FIG. 6 is a cross-sectional view taken along lines 6--6 of FIG.
3C.
FIG. 7 is a cross-sectional view taken along lines 7--7 of FIG.
3D.
FIG. 8 is a cross-sectional view taken along lines 8--8 of FIG.
3D.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is adapted to be operated from a relatively
conventional drilling rig 10 having a suitable hoist 12. Such a rig
is typically truck mounted and is adapted to move from place to
place over a subterranean ore body. As shown, a well bore 14 is
drilled through the ore body 16 and down into the formations
beneath the same to provide space for the mining apparatus 18 of
the present invention. After drilling, the well bore may be lined
if desired down to the depth of the upper portion ore body. In many
situations the sufficient lateral stability exists after drilling
that lining of the hole will not be necessary, suitable capping
being sufficient.
As shown in FIG. 1, the mining apparatus includes an upper portion
20 serving as an elongate support structure which is made up of
several sections sufficient to obtain the desired depth so that the
mining capsule 22 carried on the lower end is positioned for
operation into the ore body.
Referring now particularly to FIGS. 2 through 8, the mining capsule
portion of the apparatus of the present invention will now be
described in detail after which the supporting connections of the
upper portion of the structure together with the ground level
associated facilities will be described.
In general the mining capsule includes in its upper section a means
forming a liquid jet nozzle 30 immediately below which is mounted a
slurry discharge opening 32 having a grate 34 thereover preventing
the entry of excessively large particles. The opening communicates
interiorly of the capsule with the inlet 36 of a slurry discharge
pump 38 constructed in elongate form and positioned below the jet
and grate so that entering slurry flows into the pump under
gravity.
The entire capsule is suitably supported in an elongate cylindrical
sleeve 40 terminating in its upper end in a transverse flange 42.
This flange positions several piping elements of the structure and
is one of several located throughout the length thereof for
vertical support and positioning purposes. A high pressure water or
hydraulic inlet pipe 44 is connected through a rotatable bearing
assembly 46 to the input of a liquid jet nozzle 30. Immediately
preceding the nozzle is a section 50 of expanded pipe diameter
containing a plurality of straightening vanes 52 to assist in
maintaining laminar flow of liquid or water through the pipe to the
nozzle. The structure of the straightening vanes and nozzle as such
are disclosed in co-pending application entitled Liquid Jet Nozzle,
Ser. No. 213,363 filed Dec. 29, 1971, and assigned to the same
assignee as the present application. The bearing 46 may be of any
suitable type provided it is capable of withstanding internal
liquid pressure. The rotatable portion of the bearing is integrally
attached to the upper or inlet end of the nozzle. The nozzle makes
a turn through 90.degree. and terminates in a discharge orifice 54
which opens laterally to thereby direct a high velocity liquid jet
stream into impact contact against the material in a portion 55 of
the adjacent body to be mined. The lower end of the nozzle is
provided with a turning lug 56 which is connected through a drive
shaft 58 to an oscillating motor located beneath a seal flange 60
defining the upper end of a motor well 62 at the lowermost end of
the mining capsule. (See particularly FIG. 2B) The shroud or casing
is provided with an opening 64 therein (see particularly FIGS. 2A
and 3B). The opening extending about an arc of about 270.degree. to
320.degree. in front of the nozzle orifice in this way, the liquid
jet nozzle is rotated through a substantial arc from one side to
another in an oscillating pattern, thereby progressively moving the
region of impact of the liquid jet stream within the body from one
location to another. As the material is pulped into slurry form, it
flows backward toward the capsule where it is removed through
opening 32.
Means is provided for forming opening 30 immediately below the
liquid jet nozzle. The opening is covered with grating 34 which
prevents excessively large chunks of material from entering, such
chunks being held out and eventually reimpacted by the liquid jet
stream and broken up. The opening serves as the inlet to an
elongate positive displacement pump 38, positioned below the
orifice and connected thereto. The upper end of the pump terminates
in a relatively large diameter slurry discharge line 72 which
extends upwardly to ground level and terminates in an outlet over a
discharge pond or vessel 74. Additional pumping facilities 76 may
be incorporated in the line to provide booster service.
The pump is preferably of the elongate progressive cavity type
commonly known as a Moyno (registered trademark) type, having a
outer resilient shell or stator 78 with an inwardly facing
helically formed surface. Within the outer shell is positioned a
rotor member 80 having an outwardly facing helically formed surface
with one fewer turns than the stator 78. Such structures are known
to be useful as pumps and are disclosed by way of example in U.S.
Pat. Nos. Re. 21,374 dated Feb. 27, 1940 to R. Moineau and
2,505,136 dated Apr. 25, 1950 also to R. Moineau, and many others.
The outer member is typically constructed of resilient material
which facilitates its use for handling any slurriable material that
can be pushed through a pipe. Such pumps are of a positive
displacement type because the rotor and the stator difference in
turns defines a cavity which is progressively moved in one
direction or another as the rotor is rotated. Such pumps are
commercially available from the Moyno Pump Division of Robbins
& Meyers, Inc., Springfield, Ohio. The pump is driven by
hydraulic motor 81 mounted in the lowermost section of the capsule
in motor compartment 62.
The motor is connected through a universal drive coupling 82 to the
rotor 80 of the pump, the drive coupling arrangement being shown
particularly in FIGS. 3D and 6 through 8. As particularly indicated
in FIG. 3C, the lower end of the rotor terminates in offset
relationship to the axis of the pump so that as the same is rotated
the lower end is caused to precess or wobble about the axis. The
universal drive now to be described accommodates the axial rotation
of the drive motor to the precessive movement of the pump rotor.
The drive shaft terminates at each end in a spherical, dental
element drive, the detailed construction of each of which is the
same and is shown in FIG. 8. Thus, the driving or driven shaft
terminates in a two part housing bolted together and containing
therein upper and lower thrust bearings 90, 92 having radially
facing inward thrust bearing surfaces 94, 96 lying in contact with
a ball 98 splined to the drive shaft 95. The upper and lower
bearings are disposed to bear above and below the ball surface so
that axial thrust load can be taken in either direction through the
coupling. A suitable flexible seal 100 is retained in position
between a retaining ring 102 and lock collar 104 at the shaft end
of the coupling device and terminates in a radially spaced position
between the inner thrust bearing 90 and the cap 88a of the housing.
Rotary motion is carried through the coupling by means of a
plurality of teeth 106 carried on the outer circumference of the
ball, the teeth engaging between the teeth 108 of a ring 110
carried in fixed position in the housing and surrounding the
ball.
FIGS. 6 and 7 show sectional views which locate the various
components intermediate the motor well and the pump.
Suitable hydraulic piping and connections are provided and consist
of a pair of input lines 110, 112 and output lines 114, 116 to each
of the motors.
In addition to the foregoing, a flushing nozzle jet 118 is
connected to the high pressure water source through suitable piping
120. This jet is clearly seen in FIG. 2B and is used to control the
liquid content of the slurry pumped through the pump during
operation so as to assure that it does not become an undue load on
the pump. The jet is also useful for flooding the pump during
start-up.
Preferably an additional high pressure water jet nozzle 122 is
positioned through the bottom flange 124 of the mining capsule
housing and is directed downwardly to facilitate raising and
lowering the assembly through the well bore. Suitable piping 126
connects nozzle 122 to the high pressure water supply.
For the purpose of operating the several functions of the nozzles
and motors suitable valves 128 through 134 are incorporated in the
various lines. A pump 136 connecting the high pressure water lines
to a water reservoir 138. A separate pump 140 connects the
hydraulic line to hydraulic reservoir 142. Valve 128 is arranged
for reversible operation to provide for reverse the pump.
In operation, the apparatus of the present invention is lowered
into the predrilled well bore in stages a convenient length being
about twenty feet per stage. As each stage is lowered, it is held
on to by suitable gripping means while the next stage is connected.
Upon reaching the predetermined depth for operation the entire unit
is supported in position by the drilling rig. If necessary, valve
134 and nozzle 122 may be operated to flush material upwardly from
the lower end of the well bore and thereby facilitate movement of
the assemblage downwardly. After proper positioning the valves 128
are open and hydraulic mining is commenced. As the jet nozzle is
oscillated, the jet stream cuts the material within the ore body
and causes it to be pulped into a slurry and flow backward to the
capsule where it drains into the opening 30 and delivered through
the elongate slurry pump and pumped to the surface. By operating
through a limited arc less than a full circle sufficient material
remains in the vicinity of the well bore to prevent gross
subsidence at the surface. As the material is removed, the
overburden from within the cavity formed in the region of the
removed material usually collapses once the mining radius reaches a
significant distance. As a practical matter, distances of up to
seventy-five feet can be mined from a single well bore utilizing
the apparatus of the present invention.
Using the present invention, many underground ore bodies can be
mined even though they exist at significant depths. The only
requirements are that the material to be mined be reasonably
friable, unconstituted, and unconglomerated. Sands, gravel,
phosphate ores, friable coals, and uranium ore are examples of
materials which can be mined using the present invention.
To those skilled in the art to which this invention pertains, many
modifications and adaptations thereof will suggest themselves.
Accordingly, it should be understood that the specific disclosures
and descriptions contained herein are to be taken in an
illustrative sense and that the scope of the invention is not to be
limited thereby except in accordance with the accompanying
claims.
* * * * *