Subterranean drilling and slurry mining

Subterranean slurry mining with one or more mining nozzles which, during mining, directs a high pressure jet of liquid into a granular ore matrix to reduce the ore to a slurry which is thereafter pumped to the surface by an eductor pump including a high pressure eductor nozzle. The drilling and mining apparatus includes several different types of hydraulic control systems which operates at or below system pressure and allows the apparatus to be changed between the mining and a drilling mode. During drilling, the liquid is directed through an open foot valve and drill bit into the well cavity being drilled to wash the cuttings to the surface at which time the mining and eductor nozzles are closed. During mining the control systems close the foot valve and control the opening of the mining nozzle (or nozzles) and eductor nozzle. When the control system includes one or more control conduits that extend to the surface, the system may be used to modulate the eductor nozzle, and depending upon the control system being used to selectively open or close the mining nozzle, thereby controlling the pressure or draw-down in the cavity. Self-activating control systems are disclosed and are responsive to differences between system pressure and cavity pressure when the foot valve is closed to modulate the eductor nozzle. Other self-activating control systems may be used to selectively open and close a pair of mining nozzles without modulating the eductor nozzle, or with provision for modulating the eductor nozzle.

CROSS REFERENCE TO RELATED APPLICATIONS 
My copending United States Patent Application Ser. No. 704,277 filed on 
even date herewith and assigned to the assignee of the present invention 
discloses in detail certain components of the present drilling and mining 
apparatus not described in detail herein. Accordingly, the subject matter 
of my copending application is incorporated by reference herein. 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention pertains to improvements in subterranean slurry mining and 
more particularly relates to an apparatus for drilling and mining one or 
more layers of granular ore, such as phosphate ore, without withdrawing 
the apparatus from the well cavity between the drilling and mining phases. 
2. Description of the Prior Art 
Subterranean slurry mining of phosphates or the like is broadly known in 
the art as evidenced by United States Wenneborg et al Pat. Nos. 3,730,592 
and 3,747,696 which issued on May 1, 1973 and July 24, 1973, respectively, 
and are assigned to the assignee of the present invention. The disclosures 
of both of these patents are incorporated by reference herein. 
The modified embodiment of the apparatus disclosed in Wenneborg et al 
3,747,696 is pertinent and comprises a combination slurry drilling and 
mining apparatus which may be changed between its drilling mode of 
operation and its mining mode of operation to mine several layers of ore 
without requiring that the apparatus be pulled out of the hole or well 
cavity. However, the hydraulic control system for changing the several 
valves from the drilling mode to the mining mode requires a positive 
pressure of about 2000 psig. in the prior art device which is much greater 
than the approximately 1000 psig mining pressure. The prior art hydraulic 
system thus requires additional high pressure pumping equipment, and is 
also subject to damage due to the very high control pressures and water 
hammer type forces which may be applied to the system. 
Wenneborg et al 3,730,592 discloses a method which contemplates the use of 
surface controlled pressures equal to or in excess of the drilling 
pressure for shifting the mining nozzle, the eductor nozzle, and the drill 
bit foot valve between the drilling mode and the mining mode. In addition, 
the patentee discloses the use of control pressures which lie in a range 
between the drilling pressure and a mining pressure for modulating the 
mining nozzle. Modulation of the mining nozzle is effective to control the 
cavity pressure, and also the liquid level in the mined cavity to vary the 
mining conditions for the particular strata being mined. 
United States parent and divisional Pat. Nos. 3,155,177 and 3,316,985 which 
issued to A. B. Fly on Nov. 3, 1964 and May 2, 1967, respectively, 
disclose a method and apparatus for under-reaming or slurry mining a well, 
and can also be controlled to alternately bore deeper and mine other 
strata in the well after the first boring and mining operation have been 
completed. Valves operated by electric motors located within the tool 
string convert the apparatus from a drilling operation to a mining 
operation. The amount of force that can be applied to convert the 
apparatus from the drilling operation to the mining operation is, 
accordingly, limited by the size of the electric motors that can fit 
within the tool string. 
SUMMARY OF THE INVENTION 
In accordance with the first embodiment of the present invention, the 
combined drilling and mining apparatus includes a mining nozzle, an 
eductor nozzle, and a foot valve that operates independently of each 
other. A first hydraulic control system having one or more control lines 
to the surface maintains the mining nozzle and eductor nozzle closed 
during drilling by applying drilling system pressure to the control lines. 
One of the control lines may also be connected below the foot valves. The 
foot valve is maintained open during drilling by spring pressure and the 
lack of sufficient differential pressure drop across the foot valve to 
effect the closing of the foot valve. During mining, surface controls of 
the hydraulic control system may be regulated to modulate the eductor 
nozzle; and independently thereof, to open or close the mining nozzles and 
sense cavity pressure. 
If the drilling and mining apparatus includes two mining nozzles, a second 
hydraulic control system with the control lines leading to the surfaces is 
provided. This second control system provides for modulation of the 
eductor nozzle and also selective opening and closing of each mining 
nozzle so that only one mining nozzle is open during mining. 
A second embodiment of the eductor nozzle is provided and is self-actuated 
in that it is activated by a third hydraulic control system which merely 
senses pressure differences between well cavity pressure and the system 
pressure for opening or closing both the mining nozzle and the eductor 
nozzle. The third hydraulic control system does not include means for 
modulating the eductor nozzle. 
A third embodiment of an eductor nozzle is associated with an inverted 
self-cleaning dash pot which also forms the plug of the foot valve to 
provide a close coupled eductor pump section. A fourth hydraulic control 
system is self-activating and non-modulating for controlling the opening 
and closing of the mining nozzle and eductor nozzle of the third 
embodiment in response to pressure differences between well cavity 
pressure and system pressure. 
A fifth hydraulic control system is self-activating and is provided for use 
with either the first or fourth embodiment of the eductor nozzle. The 
fifth control system includes a spring loaded proportioning valve which 
permits modulation of the eductor nozzle by varying system pressure within 
a modulating range of about 50 psig from mining system pressure. Although 
mining system pressures between 700-1000 psig are equally effective in 
most applications, for simplicity the modulating range will be described 
as lying between 1000 to 950 psig. 
A sixth hydraulic control system is self-activating for use with either the 
first or fourth embodiments of the eductor nozzle when the drilling and 
mining apparatus includes two mining nozzles. This control system is 
activated by variations in the system pressure to modulate the eductor 
nozzle and senses momentary variations of greater pressure changes to 
alternately open and close the two mining nozzles. If desired, this sixth 
control system may be separated into two separate components with one 
component operating only the mining nozzles and/or the other component 
operating the eductor nozzle. 
A fourth embodiment of the eductor nozzle is quite similar to the third 
embodiment except that the nozzle is adapted to be modulated under the 
control of either systems having control lines to the surface or 
self-activating control systems.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The subterranean drilling and slurry mining apparatus 30 (FIGS. 1 and 2) of 
the present invention is supported on a mobile vehicle such as a barge 32 
floating in a pond 34 over the mining site. Conventional components of a 
well drilling rig 35 on the barge are employed during the drilling mode of 
operation to assemble the mining and drilling apparatus 30 section by 
section. Prior to drilling, the rig 35 is used to drive a large diameter 
conductor pipe 37 into the floor of the pond 34 to prevent the water in 
the pond from flowing into the well cavity. The apparatus is then operated 
in its mining mode to remove and collect a slurry of liquid and ore from 
the matrix being mined. After the reclaimable granular ore has been mined 
from one or more ore matrixes at the mining site, the apparatus is pulled 
from the well and is disassembled enabling the barge to be moved to 
another site. 
Although the apparatus 30 is primarily intended for use in mining phophates 
from one or more ore strata at depths between about 200 and 300 feet below 
the surface, it will be understood that the apparatus may be used at other 
depths, or for mining other types of ore including non-metallic materials. 
It will be understood that the term "ore" as used herein includes gravel, 
rocks, or any other solid that the apparatus is capable of slurry pumping 
to the surface. It will also be understood that the apparatus is capable 
of handling ore as large as four inches in diameter although the normal 
consistency of the phosphate ore is somewhat like sand. 
In general, the drilling and mining apparatus 30, when fully assembled in 
its mining mode, includes a tool string 36 that extends downwardly through 
the conductor pipe 37 and has a conventional rotary bit assembly 38 at its 
lower end. It will be understood that the bit 38 includes lower cutters 40 
and side cutters or underreamers 42 that cooperate to bore a hole or well 
cavity that is somewhat larger in diameter than the tool string. The bit 
includes a tubular water passage 41 having orifices 41' at its lower end 
which restricts the flow therethrough and aids the drilling operation by 
directing jets of water into the hole being drilled. The side cutters 42 
are pivoted inwardly when the tool is being pulled to the surface after 
the ore has been depleted from the mining site. An eductor pump section 44 
is connected to the upper end of the drill bit 38 and a mining nozzle 
section 45, which includes a mining nozzle 46, is connected to the upper 
end of the eductor section 44. A plurality of dual string pipe sections 48 
(FIG. 1) are connected together and to the mining nozzle section 45 and 
extend upwardly to the surface. Each pipe section 48 includes an inner 
string conduit section 50 (FIG. 2) defining a tubular slurry passage, an 
outer string conduit section 52 which with the inner section 50 defines an 
outer annular water passage, a control line 54 (FIGS. 4 and 5) and a 
cavity pressure sensing control line 56 which with the fluid system 
pressure between the conduits 50, 52 define a hydraulic control system 57 
(FIG. 5). The upper end of the uppermost pipe section 48 is connected to a 
swivel joint 48 (FIG. 2) that forms a portion of a mining head 60. The 
mining head 60 includes a threaded tool support coupling 62 that receives 
and is supported by a threaded swivel sub-assembly or drilling head 64. 
The drilling head 64 is supported by a hydraulically driven power swivel 66 
(FIG. 1) of the well rig 35. The power swivel 66 is guided for vertical 
movement along the frame 68 of a mast 70 and is raised and lowered by a 
power driven 100 ton cable hoist 72. The power swivel 66 and the hoist 72 
are used to support the tool string 36 during the mining mode of operation 
and also for raising (or lowering) the tool string a limited amount while 
mining, if desired, in order to change the vertical location of a jet of 
water being discharged from the mining nozzle for more effectively 
breaking up the granular ore matrix being mined. 
The drilling head 64 and power swivel 66 are also used as a unit to screw 
each section of the tool string 36 together and to direct water downwardly 
through the outer conduit 52 and through the drill bit during the drilling 
mode. Similarly, the drilling head and power swivel unit is used to 
unscrew the pipe sections of the tool string 36 from each other when the 
apparatus is being pulled from the well cavity. During the drilling and 
pulling operations a well known well loading unit 74, torque wrench 76, 
and tool slip 78 cooperate with the power swivel 66 in a manner well known 
in the art to perform the drilling and pulling functions. It will also be 
noted that the mast 70 is pivotally connected to the barge 32 and may be 
pivoted away from the well as indicated in dotted lines to permit other 
standard well drilling operations to be performed when drilling the well 
cavity. Drilling and mining liquid, hereinafter referred to as water, is 
directed into the outer conduit 52 at variable pressures and capacities by 
a pump P, control valve 82 and conduit 84. 
All components of the drilling and mining apparatus 30 of the present 
invention; except for the several embodiments of the eductor pump sections 
44, and the control systems 57 for actuating the eductor pump sections and 
the mining nozzles 46, are substantially the same as the components 
described in my above identified copending application. Accordingly, only 
the new components of the eductor pump sections and the control systems 
therefor will be described in detail. Reference may be had to my copending 
application for details of the apparatus 30 not specifically described 
herein. 
MODULATING EDUCTOR NOZZLE WITH SURFACE CONTROLS 
The first embodiments of the eductor pump section 44 (FIGS. 3-5) is 
provided with a modulating eductor nozzle 100 that operates independently 
from a self-actuating foot valve 102. 
The eductor pump section 44 includes an inner string conduit section 104 
(FIG. 2) of the inner string 50, and an outer string conduit section 106 
of the outer string 52, which outer section is provided with diametrically 
opposed slurry inlet openings 108 (FIGS. 3 and 4) of a slurry inlet 
section 110 immediately adjacent the eductor nozzle 100. 
The lower portion of the outer conduit section 106 includes a centrally 
apertured lower flange 112, an intermediate flange 114, a nozzle seat 
flange 116 and a venturi tube flange 118. The flange 118 supports the 
lower end of a venturi tube 120 (FIGS. 2 and 3) which forms the lower 
portion of the inner conduit 50. However, mining liquid (hereinafter 
referred to as water) must flow from above the upper flange 118 to a 
position below the flanges 114 and 116 without entering the slurry inlet 
section 110 except through the eductor nozzle 100 as will be described 
below. 
Accordingly, a pair of closed generally arcuate conduit sections 122 (FIG. 
4) are rigidly secured between the slurry openings 108 to assure that all 
drilling and mining water flows downwardly below the flanges 114 and 116 
for further distribution. Each arcuate conduit section 122 includes a 
portion of the outer conduit 106, an arcuate inner conduit portion 124, 
and edge portions 126 that define opposite sides of the slurry inlet 
openings 108. Grilles 128 are bolted to the edge portions 126 of adjacent 
arcuate sections and include spaced horizontal plates 130 and vertical 
rods 132 spaced about two inches apart to limit the size of the articles 
which may be drawn into the slurry openings 108. A plurality of holes 134 
(only one being shown in FIG. 3) are provided in the intermediate flange 
114 thereby allowing the water to flow therepast and through the foot 
valve 102 when the foot valve is open. 
A parabolic nozzle seat 136 having a port 137 therein is rigidly connected 
and sealed to the apertured flange 116 by capscrews extending through an 
annular ring 138, an O-ring 140 and cooperating snap ring 142. An eductor 
valve plug 144 is movable between the illustrated closed position and a 
position which opens the port 137 varying amounts by a piston 146. The 
piston 146 is received in a cylinder 148 that is rigidly secured to a base 
150, which base is secured to the flange 114 by a plurality of spacers 
152. The eductor nozzle plug 144 is bolted to a swivel plate 154 that is 
connected to the upper end of a piston rod 156 of the piston by a snap 
ring 157 and a frusto-conical collar 160 that is received in a 
frusto-conical bore in the swivel plate. The eductor nozzle plug 144 and 
piston 146 defines a plug-piston unit. Thus, the upper end of the nozzle 
plug 144 may pivot slightly relative to the axis of the piston to assure 
proper seating of the plug 144 in the port 137 when the eductor nozzle is 
closed. 
The piston 146 includes the piston rod 156 which has a lower damping 
portion 158 extending through an aperture in an intermediate wall 160 in 
the cylinder. The lower damping portion 158 of the piston rod 156 also 
enters an oversize bore 162 in the base. The bore 162 forms part of a 
control conduit 164 that is connected to control line 54. Holes 166 are 
formed in the wall 160 to permit passage of liquid past the wall 160. 
Entry of the damping portion 158 of the piston rod 156 into the oversize 
bore 162 further limits the rate of opening of the eductor nozzle 100. 
A relatively weak, small diameter compression spring 167 maintains the 
eductor nozzle 100 closed when no liquid pressure is being applied to the 
eductor section. The spring 167 is disposed between the swivel plate 154 
and a spacer 168 supported by the base 150. A heavier spring 170 is 
supported by a shim or spacer ring 172 on the base and is spaced from the 
swivel plate 154 when the eductor nozzle 100 is closed. After the nozzle 
is partially opened, the heavier spring 170 contacts the plate 154 to 
cooperate with control liquid entering control end of the cylinder from 
control line 54 to modulate the nozzle plug 144 thereby regulating the 
degree of opening of the eductor nozzle 100. 
As indicated in FIGS. 3 and 5, the control conduit or line 54 extends to 
the surface and is connected to the control end of the cylinder 148 
through the conduit 164. A valve 174 on the upper end of the control line 
54 may be actuated between positions venting the control line 54 to the 
atmosphere and directing control pressure into the control line 54 and 
cylinder 148. The cavity pressure control line 56 includes a valve 175 
(FIG. 5) at its upper end and is connected by tubing 176 (FIG. 3), a pipe 
tee 178, and a short conduit 180 to a passage 182 which communicates with 
the well cavity through the tubular passage 41 in the drill bit 38 (FIG. 
2) in an environment of clean flowing water. The drill bit is screwed into 
a flange 184 (FIG. 3) bolted to the previously mentioned flange 112. As 
indicated in FIG. 3, the lower ends of the vertical portions of the 
control lines 54 and 56 are supported by brackets 186 and 188 that are 
rigidly secured to the base 150. O-ring seals are provided to isolate the 
liquid in the control lines 54 and 56 from the surrounding drilling and 
mining liquid. If desired, flow resisting means 189 (FIG. 5) may be 
inserted in conduit 176 to provide sufficient resistance in the conduit 56 
to allow high pressure water entering the conduit to attain substantially 
mining system pressure thereby closing the mining nozzle 46. 
The foot valve 102 (FIG. 3) is self-activating and is not directly 
connected to the eductor nozzle plug 144 as was the case in my above 
mentioned copending application, but operated independently of the eductor 
nozzle plug 144. 
The foot valve 102 comprises a flanged valve seat 200 which is press fitted 
into the flange 184. A foot valve dash pot 203 includes a damping cylinder 
204 which is bolted to a cylinder support base 206 that is rigidly secured 
to a ring 202 that is bolted to the flange 184 and has a plurality of 
large flow passages 208 therein. The cylinder support 206 includes an 
upstanding shaft guide 210 which is apertured to receive an intermediate 
diameter portion of a shouldered shaft 212 to which a foot valve plug 214 
is secured. The foot valve plug 214 includes spaced guide vanes 216 that 
are slidably received in a port in the valve seat 200 and which permit 
liquid to flow into the well cavity when in the open position illustrated 
in FIG. 3. The foot valve plug 214 also includes a small diameter passage 
217 which permits a small amount of water to enter the tube 41 in the 
drill bit assembly 38 during mining when the foot valve is closed. 
A damper piston 218 is bolted to the upper end of a shouldered shaft 212 
and has its outer peripheral surface disposed within and slightly spaced 
from a cylindrical bore 220 formed in a cap 222 that is bolted to the 
upper end of the damping cylinder 204, when the foot valve is open as 
illustrated. The upper portion of the cylinder 204 is provided with a 
frusto-conical bore 224 which communicates with the bore 220 and a smaller 
diameter bore 226 within which the damping piston is seated in fluid tight 
engagement when the foot valve 102 is closed. Small diameter bleed holes 
228 and 230 are formed in the cap 222 and damper piston 218, respectively, 
for permitting liquid to slowly flow therethrough when the foot valve 102 
is being opened or closed. A spring 232 disposed between the piston 218 
and the cylinder support 206 holds the foot valve open during drilling and 
when little or no differential pressure is applied across the foot valve 
as occurs during the drilling mode. 
The modulating control system 57 for the drilling and mining apparatus 30 
is provided with a single mining nozzle 46, is illustrated in FIG. 5, and 
will be described in conjunction with the operation of the apparatus 30. 
In the discussion to follow, it will be understood that the term "system 
pressure" refers to the water pressure in the outer annular conduit 52 
(FIGS. 2 and 3) which system pressure is about 300 psig during drilling 
and is about 700 to 1000 psig during mining. The system pressure is taken 
at the surface and accordingly does not include the pressure head due to 
the height of water above the eductor nozzle section 75. It will be 
understood that the pressure in the drill bit water passage 41 is at 
substantially system pressure when the foot valve 102 is open but is at 
cavity pressure when the foot valve is closed. 
During drilling, water is directed into the outer conduit 52 at about 1400 
gallons per minute and at a system pressure at about 300 psig. At this 
time, the upper ends of the control conduits 54 and 56 (FIG. 5) are also 
open to system pressure. Thus, the hydraulic pressure acting on opposite 
sides of the piston 146 of the eductor nozzle 100 is "overbalanced" 
upwardly since the piston areas subjected to upward and downward system 
pressure are equal except for the area defined by the tip of the plug 144 
which projects through the nozzle port 137 and is subjected to the much 
lower cavity pressure. This "overbalanced" hydraulic pressure is aided by 
the spring 167 to hold the eductor nozzle 100 closed. Likewise, the cavity 
sensing control line 56 directs system pressure within a cylinder 249 of 
the mining nozzle 46 thus cooperating with a spring 242 to urge the mining 
nozzle plug-piston unit 243 and the mining nozle 45 into closed position. 
At this time, system pressure acting in the opposite direction on the 
external surfaces of the piston 243 is "overbalanced" by system pressure 
within the cylinder 240 because of area differences acted upon by 
hydraulic system pressue as indicated above. Cavity pressure control line 
56 also directs system pressure into the conduit 41 below the foot valve 
102. 
Although the flow of 1400 gallons per minute during drilling through the 
foot valve 102 creates a pressure drop across the foot valve, such 
pressure drop is not enough to cause the downward force acting on the foot 
valve to overcome the force of the spring 232. In the preferred embodiment 
of the invention, the pressure drop across the foot valve during drilling 
provides a closing force of about 135 pounds, whereas a closing force of 
about 200 pounds would be required to overcome the spring preload. Most of 
the 300 psig pressure used in drilling is dissipated across the orifices 
in the drilling bit. The pressure below the foot valve is nearly the same 
as system pressure. 
After the well cavity has been drilled to the desired mining depth and the 
apparatus 30 has been assembled in its mining mode, the system pressure is 
increased to about 450 psig corresponding to a flow rate of about 1700 
gallons per minute. This rate of flow across the foot valve increases the 
pressure drop about 50 percent thus overcoming the resisting force of the 
spring 232 (FIG. 3) causing the foot valve to commence closing. As the 
foot valve starts closing, the pressure drop increases with the opposing 
spring force initially increasing at about the same rate, thus minimizing 
the chances of the valve being closed due to a momentary hydraulic shock 
during drilling. Further closing of the valve greatly increases the 
pressure differential across the foot valve, and thus tends to cause the 
valve to rapidly close which, if permitted, would result in a severe water 
hammer shock. 
The dash pot 203 is provided to reduce the closing rate of the foot valve 
102 to a maximum of about one-half foot per second. During initial closing 
of the foot valve, water flows through the bleed passage 230 (FIG. 3) in 
the piston 218 and also between the outer periphery of the piston 218 and 
the surface of the bore 220 to provide fairly rapid initial closing 
movement. As the piston 218 moves further down into the frusto-conical 
surface 224, the flow of liquid around the periphery of the piston 
gradually decreases, and such peripheral flow terminates (or substantially 
terminates) when the piston enters the small diameter bore 226. The 
closing rate of the piston 218 and foot valve plug 214 is maintained 
substantially constant since the water within the dash pot cylinder 204 
must then flow only through the small bleed hole 230 when permitting final 
closing of the foot valve 102. The pressure below the foot valve decreases 
as the foot valve closes, being substantially equal to cavity pressure 
when the valve is closed. During this point in the cycle control vavle 175 
(FIG. 5) in the cavity sensing line 56 is closed to prevent discharge of 
system pressure. When the foot valve is closed, the pressure therebelow is 
substantially cavity pressure thus opening the mining nozzle 46. After the 
mining nozzle is open, the valve 175 may be opened to a metered flow of 
compressed air thus permitting cavity pressure to be measured and recorded 
at the surface. 
With the mining nozzle open and the foot valve 102 closed, a high pressure 
jet of water is directed into the ore strata at about 700-1000 psig thus 
reducing the ore to a slurry. At this time the pump capacity is about 6000 
to 4000 gallons per minute. As fully discussed in my aforementioned 
copending application, the tool string 36 is rotated during mining thus 
enabling the jet of water to form a large generally cylindrical cavity in 
the ore matrix by reducing the granular ore than had been in the cavity to 
a slurry of ore and water. 
In order to pump the slurry to the surface through the venturi tube 120 
(FIG. 2) and the inner pipe string 50, the eductor nozzle is partially or 
completely opened by actuation of the control valve 174 (FIG. 5) at the 
surface. When the valve 174 is fully opened to receive full system 
pressure of, for example, 1000 psig, the hydraulic pressure acting on both 
ends of the eductor nozzle piston 146 will be at system pressure and will 
therefore be hydraulically "overbalanced" to the closed position. This 
force plus the force of the spring 167 will hole the eductor plug 144 
closed, causing little if any slurry to be pumped to the surface through 
the inner pipe string 50. If the valve 174 is fully vented to the 
atmosphere, the system pressure of 1000 psig will overcome the closing 
force of springs 167 and 170 thus fully opening the eductor nozzle 100 
thereby directing slurry at its maximum rate to the surface through the 
inner pipe string 50 for collection. 
If it is desired to control or vary cavity pressure, or to produce draw 
down of the liquid level below the mining nozzle, the control valve 174 
(which may be automatically controlled) may be adjusted to modulate the 
eductor nozzle plug 144 thereby controlling the rate at which the slurry 
is pumped to the surface. 
In an apparatus 30 designed to operate with a drilling system pressure of 
about 300 psig and a mining system pressure of about 1000 psig, the 
modulating control pressure preferably lies within a modulating range of 
between about 150 to 500 psig. It is, of course, understood that this 
pressure range is given by way of example and that the pressure required 
when mining at substantially different levels or with different size 
equipment may vary considerably. 
As mentioned previously, the relatively weak spring 167 (FIGS. 3 and 5) 
permits the eductor plug to open a small amount before the heavy spring 
170 is contacted by the swivel plate 154. The thickness of the spacer ring 
172 may be selected as desired and such selection determines the 
percentage of full open that the nozzle plug will reach prior to engaging 
the heavy spring. For example, an initial nozzle opening of 60 percent, 
which is achieved by reducing the pressure in the control line 54 to 
slightly above 500 psig, provides a modulating range of 40 percent. Thus, 
by varying the control pressure between about 500 to 150 psig in line 54 
by selective actuation of the valve 174, the eductor nozzle opening is 
varied between its 60 percent open and full open positions. 
SURFACE CONTROLLED DUAL MINING NOZZLE CONTROL SYSTEM WITH MODULATING 
EDUCTOR NOZZLE 
FIG. 6 illustrates an eductor nozzle modulating control system 57a for a 
drilling and mining apparatus 30a which is substantially the same as the 
above described apparatus 30 except that two mining nozzles 46' and 46a 
are provided instead of a single mining nozzle. As indicated in greater 
detail in my aforementioned copending application, two or more layers of 
granular ore are sometimes present in the area being mined. Thus, it 
becomes advantageous if both layers can be mined without requiring that 
the apparatus be changed from its mining mode to its drilling mode and 
back to its mining mode in order to mine the two layers of ore. This can 
be accomplished by the alternate use of two (or more) mining nozzles 46' 
and 46a positioned at the desired height to mine associated ore layers or 
matrixes. It will be understood that the ore which is reduced to a slurry 
by each mining nozzle 46', 46a will gravitate downwardly and will be 
pumped to the surface by the same eductor nozzle 100a and the components 
associated therewith. 
Since the apparatus 30a and the control system 57a are substantially the 
same as those previously described, only the differences will be described 
in detail. Parts of the control system 57a which are equivalent to the 
control system 57 will be assigned the same numerals followed by the 
letter "a". 
As indicated in FIG. 6, control line 54a with control valve 174a therein is 
connected to the cylinder 240' of the mining nozzle 46' and to one end of 
a shuttle valve 250 having a core 252 therein that is shifted by pressure 
differences acting on its opposite ends. Similarly, the control line 56a 
with control valve 175a therein is connected to the cylinder 240a of 
mining nozzle 46a and to the other end of the shuttle valve 250. A branch 
conduit 254 is connected between the control conduit 54a and a cross 
passage 256 in the valve 250 which communicates with the cylinder 148a of 
the eductor nozzle 100a through a conduit 258 when the core 252 is shifted 
to the left as indicated in FIG. 6. In order to shift the core 252 to the 
illustrated position, the control valve 175a is open to system pressure 
(for example about 1000 psig) thus maintaining the mining nozzle 46a 
closed. The control valve 174a is completely vented or is partially vented 
to provide a control pressure that is less than system pressure thus 
opening mining nozzle 46'. At this time, a branch conduit 260 connected 
between the control conduit 56a and the shuttle valve 250 is closed by the 
core 252. 
With the shuttle valve 250 positioned as above described, the control valve 
174a may be manually or automatically controlled to vary the pressure 
between about 500 t 150 psig in to line 54a, conduit 258, and eductor 
nozzle cylinder 148a. This varying control pressure in the eductor nozzle 
cylinder 148a will cause the eductor nozzle to modulate as previously 
described. Also, control pressure within the modulating range of 150-500 
psig will not be sufficient to close the mining nozzle 46' as described in 
more detail in my cross referenced copending application. Complete venting 
or 0 psig in the cylinder 148a will obviously fully open the eductor 
nozzle. The self-actuating foot valve 102a remains closed during mining 
and is controlled in a manner identical to that previously described. 
When it is desired to mine the other ore strata by opening mining nozzle 
46a and closing mining nozzle 46', valve 175a is vented or partially 
vented and valve 174a is open to the 1000 psig mining system pressure thus 
closing nozzle 46' and shifting the shuttle valve core 252 to the right 
(FIG. 6). At this time branch conduit 254 will be closed by the core 252, 
and branch conduit 260 will be open to the eductor nozzle cylinder 148a 
through a passage 262 in the shuttle valve and the conduit 258. The valve 
175a may then be adjusted to vary the control pressure to the cylinder 
148a of the eductor nozzle 100a between about 500 and 150 psig thus 
modulating the eductor nozzle as previously described. 
SELF ACTUATING EDUCTOR NOZZLE 
A second embodiment of the eductor pump section 44b providing a 
self-actuating form of eductor nozzle 100b is illustrated in FIGS. 7 and 8 
and requires no control conduits to the surface in order to open and close 
the nozzle plug 144b relative to its seat 136b (FIG. 8). The eductor 
nozzle 100b is shifted between its drilling mode (at which time it is 
closed) and its mining mode (at which time it is fully opened) in response 
to detecting differences between the system pressure and the well cavity 
pressure. It will be understood that this eductor nozzle will be used when 
modulation of the eductor nozzle is not required for the particular type 
of granular ore being mined. 
Since all components of the apparatus except the control system 57b and the 
eductor nozzle 100 b are the same as previously described in regard to the 
first embodiment of the invention, only the differences between the two 
embodiments will be described in detail. Parts of the eductor nozle 100b 
which are similar to those of the first embodiment will be assigned the 
same numerals followed by the letter "b". 
The eductor nozzle plug 144b is bolted to a swivel plate 154b (FIG. 7) and 
is connected to the upper end of the piston rod 156b of a piston 146b that 
is larger than the previously described piston 146 (FIG. 3) in order to 
provide quicker opening of the eductor nozzle. The piston 146b is received 
in a cylinder 148b having a flow restricting baffle 160b near its lower 
end. The baffle is provided with holes 166b and is drilled to receive the 
lower damping portion 158b of the piston rod 156b. 
As the piston moves downwardly to its full open position, the lower end 
158b of the piston rod enters the counter bore 162b in the base 150b which 
restricts fluid flow and limits the rate of movement of the piston 146b 
and eductor plug 144b. The passage 164b in the base 150b and a larger 
diameter conduit 180b establishes a flow passage between the cavity below 
the foot valve 102b (FIG. 8) and the eductor nozzle cylinder 148b. A pipe 
tee 178b in the conduit 180b, a section of tubing 176b, and the cavity 
pressure control line 56b establishes communication between the cavity 
below the foot valve and the cylinder 240b of the mining nozzle 46b. The 
mining nozzle plug 243b is urged towards its closed position by a spring 
242b and is opened when the force developed by system pressure on the 
output side of the plug 243b is greater than the sum of spring force and 
the force developed by the control pressure within conduit 56b and 
cylinder 240b acting on the other side of the plug 243b. 
The eductor nozzle 100b differs from the nozzle 100 of the first embodiment 
of the invention in that a single spring 266, rather than two springs, is 
disposed between the swivel plate 154b and the base 150b. 
During drilling, the pressure below the foot valve and in the control lines 
is nearly the same as system pressure. Since it acts on a much larger area 
than system pressure it serves to keep eductor and mining nozzles closed 
during drilling in conjunction with spring forces. 
In operation of an apparatus which includes the self-actuating eductor 
nozzle 100b, the mining nozzle 46b, and the foot valve 102b; it will be 
understood that prior to introducing water into the tool string 36b (FIG. 
7) that the spring 242b holds the mining nozzle closed, spring 266 holds 
the eductor nozzle 100b closed, and the spring 232b holds the foot valve 
102b open. During drilling, the system pressure is about 300 psig and the 
water flow across the foot valve is about 1400 gallons per minute which is 
insufficient to create a sufficient pressure drop across the foot valve to 
close the foot valve by overcoming the pressure of spring 232b. Thus, 
during drilling the pressure below the foot valve is close to system 
pressure and is directed into both cylinders 148b and 240b. This pressure 
acts on the full piston area of nozzle plugs 243b and 146b, while system 
pressure acts on the piston area less the nozzle area, which is exposed to 
a much lower cavity pressure. 
During mining, the foot valve 102b operates as previously described in 
regard to the first embodiment of the invention. In this regard the system 
pressure of, for example, about 450 psig and flow rate of about 1700 
gallons per minute across the foot valve creates a sufficient pressure 
drop to close the foot valve 102b in a controlled fashion through the 
action of the dash pot 203b. Since the foot valve closes comparatively 
slowly, the relatively large area of the piston 146b that is exposed to 
the 450 psig system pressure on one side, and the gradually decreasing 
pressure on the other side, causes the eductor nozzle plug 144b to at 
least substantially open prior to the foot valve closing against the 
urging of the spring 232b. The creation of a low pressure below the foot 
valve and the transmission of low cavity pressure to the cylinder 240b of 
the mining nozzle 46b thus permits system pressure to fully open the 
mining nozzle 46b against the urging of spring 242b. 
FOOT VALVE WITH SELF-CLEANING DASH POT AND SELF-ACTIVATING NON-MODULATING 
CONTROL SYSTEM 
A third embodiment of the eductor pump section 44c and conrol system 57c is 
illustrated in FIGS. 9 and 10. This section is similar to the first 
embodiment of the invention and differs primarily in that cylinder 204c of 
the dash pot 203c is inverted and is an integral portion of the plug 214c 
of the foot valve 102c. Thus, only the differences between the two 
embodiments will be described in detail, and parts of the third embodiment 
that are similar to the first embodiment will be assigned the same 
numerals followed by the letter "c". 
The valve seat 136c of the eductor nozzle 100c receives an eductor nozzle 
plug 144c that has guide fins 270 on its outer periphery and has a piston 
272 formed on its lower end. The piston 272 is slidably received in a 
cylinder 274 having a flanged base 276 that is rigidly secured to the 
flange 116c by capscrews and spacers 278. A compression spring 280 is 
disposed between the lower wall 282 of the cylinder 274 and the upper wall 
of a cavity in the eductor nozzle plug 144c, and urges the eductor nozzle 
plug 144c toward its closed position. 
A control conduit 283 is connected between the cylinder 240C (FIG. 10) of 
the mining nozzle 46c and the eductor nozzle cylinder 274. The base 276 of 
the eductor nozzle 100c is apertured to receive a tube 284 rigid therewith 
and projecting downwardly therefrom. The lower end of the tube 284 is 
opened to pressure below the foot valve and accordingly directs this 
pressure into both the eductor nozzle cylinder 274 and the mining nozzle 
cylinder 240c when the foot valve 102c is closed. The damper piston 218c 
is secured to the tube 284 by snap rings or the like and is provided with 
a bleed passage 230c. 
As mentioned above, the dash pot cylinder 204c is inverted relative to the 
dash pot of the first embodiment of the invention. The cylinder 204c has a 
cap 222c with a bleed hole 228c therein bolted to the cylinder and is 
centrally apertured to slidably receive the tube 284. The spring 232c is 
disposed between the cap 222c and the piston 218c and normally urges the 
foot valve 102c to its open position. The lower end of the cylinder 
defines the foot valve plug 214c which is provided with a large diameter 
central port 286 that establishes free communication between the cavity 
below the foot and the interior of the cylinder 204c below the piston 
218c. The foot valve plug 214c includes guide vanes 216c which are 
received in the port of the valve seat 200c that is secured to the flange 
184c to which the tubular drill bit 38 (FIG. 2) is secured. Thus, when the 
foot valve 102c is open as illustrated in FIG. 9, water is directed 
between the guide vanes 216c, through the foot valve seat 200c and through 
the tubular drill bit 38 into the well cavity being drilled. When the foot 
valve moves downwardly into the closed position, the major flow of water 
is prevented from entering the cavity and is split to flow through the 
eductor nozzle 100c and the mining nozzle 46c (FIG. 10) both of which are 
open at this time. 
As illustrated in FIG. 9, as the foot valve moves downwardly the outer 
periphery of the damper piston 218c is progressively moved within the 
large diameter cylindrical bore 220c, the frusto-conical bore 224c, and 
the small diameter bore 226c thereby progressively increasing the 
resistance to the flow of water across the piston and progressively 
reduces the rate of closing movement of the foot valve. 
Since the tube 284 is positioned coaxially within the inner conduit 50c and 
the outer conduit 52c of the tool string 36c, the spacing between the 
eductor nozzle 100c and the foot valve 102c is much less than in the 
previously described embodiments of the invention. Also, the flange 184c 
is connected by screw threads rather than by bolts to the outer pipe 
section 52c, which threaded connection is a much faster and less expensive 
manner of connecting the components together. 
In operation of the eductor pump section 44c and the mining nozzle 46c of 
the third embodiment of the invention, reference is directed to FIGS. 9 
and 10. During drilling, about 1400 gallons per minute of water at a 
system pressure of about 300 psig is directed between the inner and outer 
pipe sections 50c, 52c and through the foot valve 102c into the well 
cavity. As this time the pressure drop across the foot valve 102c is 
insufficient to reduce the pressure below the foot valve enough to 
overcome the resilience of the dash pot spring 232c, the eductor nozzle 
spring 280, or the mining nozzle spring 242c. Thus, during drilling the 
foot valve remains open and the eductor nozzle and mining nozzle are both 
held closed by spring force and fluid pressure. 
At the start of mining, the capacity of water is increased to about 1700 
gallons per minute and the pressure is increased to a system pressure of 
about 450 psig. The increased flow of water through the foot valve 102c 
increases the pressure drop across the foot valve enough to cause the foot 
valve to move downwardly against the urging of the spring 232c. As the 
foot valve closes, the pressure below the foot valve is reduced enough, 
compared to the 450 psig system pressure, to allow system pressure to 
overcome the force of the springs 280 and 242c thus opening the eductor 
nozzle 100c and the mining nozzle 46c. The rate at which the foot valve 
102c is allowed to close is controlled gy the dash pot 203c. Since the 
water within the dash pot must flow between the piston 218 (FIG. 9) and 
the internal surface of the cylinder 204c in order for the foot valve to 
close, the gradual decrease in flow passage size, as determined by the 
surfaces 220c, 224c and 226c, as the cylinder moves downwardly results in 
a controlled closing of the foot valve in the face of increasing pressure 
drop across the valves. During final closing of the foot valve, the water 
within the cylinder above the piston 218c must flow through bleed holes 
230c and 228c. 
As the foot valve 102c closes, the eductor nozzle 100c and mining nozzle 
46c begin to close. Since the cylinders 274 and 240c are both filled with 
water which must be displaced before the nozzle plugs 144c and 243c can 
open, it is apparent that the relatively small passages in the tube 284 
and conduit 283 will restrict rate of flow of liquid therethrough. Thus, 
the size of these passages may be selected so as to control the rate of 
opening of the eductor nozzle 100c and mining nozzle 46c to thereby reduce 
water hammer to an acceptable degree. 
It will be appreciated that during mining when the foot valve 102c is 
closed, a small amount of water will flow through bleed passages 228c and 
230c into the well cavity therebelow thus tending to maintain the dash pot 
203c free from sand and dirt or the like. Likewise, when the foot valve is 
open, any contaminates that enter the dash pot will be flushed therefrom 
into the well cavity through the relatively large annular opening defined 
between the outer periphery of the piston 218c and the port 220c. This 
water and debris then flows through opening 286 into the well cavity. 
FOOT VALVE WITH SELF-CLEANING DASH POT AND MODULATING CONTROL SYSTEM 
A fragment of a fourth embodiment of the eductor pump section 44x is 
illustrated in FIG. 11, and is identical to the third embodiment except 
that the eductor nozzle 100x is designed so that it may be modulated. 
Thus, only the differences will be described in detail, and components of 
the eductor pump secion 44x that are equivalent to the eductor pump 
section 44c will be assigned the same numerals followed by the letter x. 
The eductor nozzle 100x includes a flanged base 276x that is thicker than 
the base 276 (FIG. 9) and has a passage 324 therein that establishes 
communication between control conduit 283x leading to the associated 
mining nozzle and the tube 284x of the foot valve 102x which communicates 
with cavity pressure when the foot valve is closed. It is particularly 
noted that the eductor nozzle cylinder 274x does not communicate through 
the tube 284x to cavity pressure, but instead is connected to a control 
line 326 by a port 328. 
If surface conrol is desirable, the eductor pump section 44x is substituted 
for the pump section 44 (FIG. 5) or 44b (FIG. 6) and is controlled by 
control systems similar to those described in connection with FIGS. 5 and 
6. The resulting operation of the pump section 44x is substantially the 
same as described in those systems. In this regard, conduits 326 and 283x 
are connected to conduits 54 and 56, respectively, if a control system 
similar to the system illustrated in FIG. 5 is used; and are connected to 
control lines 54a and 56a respectively if the FIG. 6 system is to be used. 
CONTROL SYSTEM FOR MODULATING EDUCTOR NOZZLE WITHOUT CONTROLS TO THE 
SURFACE 
In FIG. 12 a hydraulic control system 57d is illustrated for modulating the 
eductor nozzle 100 during mining without requiring special control lines 
to the surface. Although the control system 57d will be described in 
relation to the previously described components of the first embodiment of 
the invention, it will be understood that such control system may also be 
used with the fourth embodiment of the invention if desired. 
Since the mining nozzle 46, eductor nozzle 100 and foot valve 102 are the 
same as described in the first embodiment of the invention, only the 
modulating control system 57d will be described in detail, and parts of 
the system 57d that are equivalent to the system 57 will be assigned the 
same numerals folowed by the letter "d" . 
The control system 57d comprises a pilot actuated proportioning valve 302 
having a core 304 therein which is held in the illustrated position by a 
preloaded spring 306 when system pressure is below the drilling pressure 
of between about 300-400 psig. When in the illustrated drilling position, 
system pressure SP in the tool string 36 (FIGS. 1 and 2) acts through a 
conduit 307 on the upper end of the core 304 tending to move it 
downwardly. This force is counteracted by the force of the spring 306 plus 
the pressure below the foot valve 102d, which pressure is substantially 
system pressure and is communicated to the other end of the proportioning 
valve 302 by a conduit 308. a branch conduit 310 connects the pressure 
conduit 308 to a port 312 in the valve which at this time is closed by the 
core 304. Similarly, the system pressure conduit 307, which is connected 
to the water supply at a point above the foot valve is connected by a 
branch conduit 313 to a port 314 in the valve and a passage 316 through 
the core 304. The passage 316 is connected to the eductor nozzle cylinder 
148d by a conduit 318 while the mining nozzle cylinder 240 is connected 
below the foot valve by a conduit 320. Thus, when the system pressure is 
approximately drilling pressure, that pressure is also communicated into 
cylinders 148d and 240d thus holding both the eductor nozzle 100d and the 
mining nozzle 46d closed. The self-activating foot valve 102d will be open 
during drilling as previously described. 
As system pressure is increased to full mining pressur of, for example, 
about 1000 psig, the foot valve 102d is closed as previously described 
resulting in cavity pressure below the foot valve. The 1000 psig system 
pressure also enters the conduit 307 and shifts the core 304 to the other 
end of its stroke at which time a passage 322 in the core communicates 
with port 312 and conduit 318 thus venting the eductor nozzle cylinder 
148d to the very low cavity pressure. The mining nozzle 240d is likewise 
vented to cavity through conduit 320. The high system pressure acting on 
the eductor nozzle and the mining nozzle then overcomes the cavity 
pressure plus the pressure applied by springs 167d, 170d and 242d to fully 
open the eductor nozzle 100d and the mining nozzle 46d. 
Modulation of the eductor nozzle 100d is accomplished by selecting and 
preloading the proportioning valve spring 306 so that it will cause the 
valve to shift through its entire modulating range in response to a system 
pressure variation of about 50 psig. 
For example, if the modulating range of the nozzle is 40 percent, i.e., 60 
percent open to fully open as previously described, and if 1000 psig is 
the maximum mining system pressure, variations of system pressure between 
950 and 1000 psig will cause the eductor nozzle 100d to modulate through 
its entire 40 percent range. In accordance with the above example, it will 
be apparent that when the system pressure is 950 psig, the proportioning 
valve 302 will be partially opened and the swivel plate 154d will be 
contacting the heavy spring 170d. If the system pressure is increased to 
975 psig for example, the heavy spring 170d is compressed unit the force 
developed by system pressure acting downwardly on the upper surface of the 
piston 146d is equal to the sum of the forces of the springs 167d, 170d 
and the force developed by the control pressure within the cylinder 148d, 
which cylinder pressure is controlled by the valve 302 to lie between 
system pressure and cavity pressure. Thus, each pressure setting between 
950 and 1000 psig will cause the eductor nozzle 100d to open different 
amounts. The system pressure received from pump P (FIG. 1) may be varied 
by adjusting a valve 82 in the water inlet conduit 84, or by varying the 
speed of the pump P. 
It will be understood that shifting the proportioning pilot valve 302 by 
varying the system pressure through the 50 psig modulating range will 
cause the proportioned pressure entering the eductor nozzle cylinder 148d 
to vary between about 150-500 psig. 
DUAL MINING NOZZLE CONTROL SYSTEM WITHOUT SURFACE CONTROLS 
A hydraulic control system 57e is diagrammatically illustrated in FIG. 13 
and is designed for use with a mining and drilling apparatus having two 
mining nozzles 46e and 46". The control system 57e is self-activating, 
includes no control lines to the surface, and is capable of both 
modulating the eductor nozzle 100a and also selectively opening and 
closing the mining nozzles 46e and 46" in response to selective variations 
in the system pressure. 
The eductor modulating portion 57de of the control system 57e is 
structurally the same, and is operated is the same way, as the modulating 
control system 57d illustrated in FIG. 1 except for the points at which 
the nozzle 46e and 46" are connected into the system 57e of the control 
system 57e will not be described in detail and parts of the system 57de 
which are equivalent to those of the system 57d will be assigned the same 
numerals followed by the letter "e". 
The control system 57e includes conduits 332, 334 communicating with system 
pressure SP at a point in the outer water supply conduit 52 (FIG. 2). 
Conduits 336, 338, 240 and 308e are connected to vents V or the pressure 
existing at a point below the foot valve 102e, which pressure is 
substantially system pressure when the foot valve is open and is cavity 
pressure when the foot valve is closed. 
After the drilling operation has been completed and the apparatus 30 (FIG. 
1) is assembled in its mining mode, the pump P is started and directs 
water through the valve 82 and conduit 84 into the outer annular passage 
defined between the outer conduit 52 and inner conduit 50 of the tool 
string 36. As the water pressure within the conduit 52 reaches the mining 
system pressure of, for example, about 450 psig and is flowing at a rate 
of about 1700 gallons per minute, the foot valve 102e (FIG. 12) closes and 
the eductor nozzle 100d fully opens as previously described in regard to 
the control system 57d (FIG. 12). During this time the system pressure SP 
enters conduits 332 and 334 causing proportioning valve core 304e to move 
downwardly against the urging of spring 306e thereby venting eductor 
nozzle cylinder 148e to cavity through passages 318e, 322e, 310e and 308 
e. 
System pressure SP is also directed upwardly through a conduit 342, a 
parallel passage 344 in the core 346 of a shuttle valve 348 and through 
conduit 350 into the cylinder 240" of the upper mining nozzle 46" thereby 
holding the upper mining nozzle closed. At this time the cylinder 240e of 
the lower mining nozzle 46e is vented to cavity through a conduit 352, 
parallel passage 354 in core 346, conduit 356 and the conduit 308e to the 
well cavity. 
The high pressure liquid which enters conduit 332 at system pressure SP 
initially flows through a passage 358 in the core 360 and of a valve 362. 
The high pressure liguid then flows through a conduit 364, a parallel 
passage 366 in the core 368 of a valve 370, and through a conduit 372 into 
one end of a valve 374 having a core 376 therein. The core 376 is 
connected to the core 346 of valve 348 by a link 378. High pressure liquid 
entering the end of the valve 374 then shifts the cores 346 and 376 from 
the illustrated positions to the left. Shifting the core 346 from its 
parallel passage position to its cross passage position closes lower 
mining nozzle 46e by directing high pressure liquid into the cylinder 240e 
through cross passage 380; and opens the upper mining nozzle 46" by 
venting cylinder 240" to cavity pressure through a cross passage 382. 
Shifting the core 376 to the left performs no function until the core 360 
of valve 362 is fully shifted to the left. In this regard, high pressure 
liquid entering conduit 332 flows through conduit 384 into the right end 
of the valve 362 thus slowly shifting the core 360 to the left against the 
urging of a spring 386. The conduit 336 which vents the other end of the 
valve 362 to cavity pressure includes a flow resisting valve 388 through 
which the water in the left end of the valve 362 must flow before the core 
360 can shift fully to the left. The flow resisting valve 388 is adjusted 
to slow the rate of movement of the core 360 sufficiently to permit all of 
the above described functions to occur before the core shifts. 
After the core 360 shifts to the left, high pressure liquid flows through a 
passage 390 in the core 360, a conduit 392, parallel passage 394 in 
shifted core 376, and conduit 396 to the right end of the valve 370 thus 
shifting its core 368 to the left. The liquid in the other end of the 
valve 370 is vented to the well cavity through conduit 398, parallel 
passage 400 in the core 376 and conduit 340. Shifting of the valve core 
368 has no immediate effect on the mining nozzle 46" and 46e, but presets 
the control system 57e to shift the mining nozzle upon reducing the system 
pressure below the force pressure of the spring 386. 
As mentioned previously in regard to the modulating control circuit 57d 
illustrated in FIG. 12, modulation of the eductor nozzle is preferably 
accomplished by varying the system pressure within the range of between 
about 950 to 1000 psig. The pressure of spring 386 which controls valve 
362 is preferably set to balance a system pressure of about 900 psig thus 
permitting full modulation of the eductor nozzle 100e without effecting 
the valve 362. 
When it is desired to open mining nozzle 46" and close mining nozzle 46e, 
the system pressure is reduced to slightly below 900 psig by throttling 
valve 82 (FIG. 1). The spring 386 (FIG. 13) thus returns the valve core 
360 to its illustrated right hand position and system pressure is 
thereafter increased to the desired mining pressure by opening control 
valve 82 (FIG. 1). High pressure fluid then flows through conduit 332 
(FIG. 13), passage 358 in the valve core 360, conduit 364, a cross passage 
404 in the core 368, and a conduit 406 to the left end of the valve 374 
which returns both cores 376 and 346 to their illustrated positions. 
Shifting the core 376 to the right causes low pressure liquid to be vented 
from the right end of the valve 374 through the conduit 372, cross passage 
410 and conduit 338 to the well cavity. Shifting the core 346 to the 
illustrated position opens mining nozzle 46e and closes mining nozzles 46" 
as previously described. As the pressure from lines 332 and 384 again 
shift the core 360 to the left, high pressure liquid flows from conduit 
332 through passage 390, conduit 392, cross passage 414 in the core 376, 
and conduit 398 thus shifting valve core 368 to its illustrated right hand 
position. At this time liquid in the right end of the valve 370 is vented 
through conduit 396, a cross passage 416 and the conduit 340 to cavity. 
Thus, the above procedure is repeated each time the system pressure is 
dropped below 900 psig and thereafter returned to mining pressure. During 
mining, the eductor nozzle 100e may be modulated as desired, without 
affecting the mining nozzles. 
When system pressure is reduced to 0, the foot valve 102e is opened by the 
spring 232e, the eductor nozzle 100e is closed by springs 167e and 170e, 
and both mining nozzles 46e and 46" are closed by springs 242e and 242". 
Although the control system 57e has been described in conjunction with a 
modulating eductor nozzle, it will be understood that the upper portion of 
the system 57e may be used independently of the modulating system 57de. If 
used in this way, the conduit 342 would communicate with system pressure 
and the conduit 356 would communicate with cavity. In such a system, any 
of the herein described eductor nozzles and foot valves could be used, and 
the eductor nozzle could be controlled by a self-activated system similar 
to FIG. 8, or by a system having a control line to the surface such as 
control line 54 (FIG. 5). 
From the foregoing description it will be apparent that the drilling and 
mining apparatus of the present invention includes several modified forms 
of eductor pump sections wherein the foot valve is self-activating in 
response to the rate of flow of liquid therethrough. The foot valve is 
operated independently of the eductor nozzle and includes a dash pot which 
reduces the rate of closure of the foot valve to minimize "water hammer" 
which "water hammer" is further minimized by allowing the eductor nozzle 
to at least partially open prior to full closing of the foot valve. 
Several hydraulically operated control systems are included in the 
invention and permit modulation of the eductor nozzle when either one or 
two mining nozzles are being used without effecting the position of the 
mining nozzle or nozzles during modulation. When two mining nozzles are 
being used, the control system is effective to open only one mining nozzle 
at a time. The several hydraulic control systems may either include 
separate control lines to the surface, or may be self-energizing and be 
devoid of control lines to the surface. In all control systems, the 
pressure involved are equal to or less than mining system pressure which 
is between about 700-1000 psig in the illustrated preferred embodiments. 
Also, each control system is capable of adjusting the several operative 
components of the drilling and mining apparatus between the drilling mode 
and mining mode without withdrawing the tool string from the well cavity. 
In all configurations control pressure assists in holding the eductor and 
mining nozzles closed during drilling. 
Although the best mode contemplated for carrying out the present invention 
has been herein shown and described, it will be apparent that modification 
and variation may be made without departing from what is regarded to be 
the subject matter of the invention.