Method And Apparatus For Aligning A Charged Particle Beam

Abstract

There is disclosed apparatus for mining and excavating through rocky terrain without a mechanical tool or machine which must be made rugged enough to withstand the forces and impacts necessary to break rocks. The excavation is carried out with an electron beam which is projected against the rock. The beam is conducted from a generator through a long tube, which may be 20 feet long or more through one or more internal apertures, and is emitted at the end of the tube through an exit aperture. The generator and tube may be mounted on the turret of a vehicle so that the tube can swing in an arc of large angle in the plane of a rocky seam or at any angle transverse to this plane. The beam is centered in, at least, the exit aperture by apparatus which responds to any uneven generation of X-Rays around the periphery of the exit aperture.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The following patents and applications in the United States are incorporated herein by reference:

Application Ser. No. 756,653 filed Aug. 30, 1968 (now U.S. Pat. No. 3,556,600 dated Jan. 19, 1971) to William E. Shoupp and Berthold W. Schumacher for "Distribution and Cutting of Rocks, Glass and the Like."

Application Ser. No. 756,654 filed Aug. 30, 1968, (now abandoned in favor of continuation application Ser. No. 105,113 filed Jan. 8, 1971 which matured into U.S. Pat. No. 3,725,633 dated April 3, 1973) to Berthold W. Schumacher and Robert E. La Croix for "Corpuscular Beam In The Atmosphere."

Application Ser. No. 79,732 filed Mar. 16, 1970 (now U.S. Pat. No. 3,589,351 dated June 29, 1971) to William E. Shoupp and Berthold W. Schumacher for "Cutting of Rocks, Glass and the Like."

BACKGROUND OF THE INVENTION

This invention relates to the art of mining and/or excavating in rocky terrain and has particular relationship to such mining or excavating with corpuscular beams (for example electrons or ions like He.sup.+ or H.sup.+) emitted into the atmosphere and specifically with an electron beam of high power projected into the atmosphere. The above-listed applications disclose the rupturing of rocks by projecting a highpower electron beam on the rocks. The beam penetrates into the rock breaking, spalling and/or melting the rock.

Typical of the mining with which the invention concerns itself is mining for gold. The gold is usually deposited in a narrow rocky seam which must be broken to remove the material from which the gold is derived. In accordance with some of the teachings of the prior art, the removal of material from the seam is carried out with the aid of a manually operated machine or tool capable of breaking the rock by applying continuous forces of high magnitude to the rocks. Such a tool must be rugged to withstand the high forces and must be firmly supported or braced to apply the forces and absorb their reactions. In practice this machine is laboriously operated step-by-step into the seam by an attendant who sits behind the excavating tool. After every few steps the supports for the machine are relaxed, the machine is advanced, and then secured in the new position and the necessary forces are impressed to make an advanced penetration into the seam. (See the African Mining Journal Nov. 29, 1968, page 1,245 -- One Year of Rock-Cutting Trails. Swiss Journal TECHNICA, Birkhouser Verlag, Nov. 19, 1968 -- Gerd. Kampf-Emden, Pgs. 1,635-1,639 -- "Stationen des vollmechanischen Tunnelvortriebs;" Engineering and Mining Journal, McGraw-Hill, April 1968 -- "USBM Examines Exotic Ways of Breaking Rock," pgs. 85-92.)

SUMMARY OF THE INVENTION

In accordance with this invention the mining or excavation is carried out by projecting a corpuscular beam on the rock face of the mine or excavation. The beam is conducted from the corpuscular source over a long tube of relatively small cross-sectional area and is emitted on the rock at the end of this tube. By impingement of the beam the rock face is fractured to a depth of 1/4 to 10 inches. The debris from the fracture may be removed progressively as it is produced and the fracturing continued until the desired narrow seam is mined out.

Typically, the corpuscular beam generator may be mounted so that it can be moved in three dimensions, over a high-angle arc longitudinal of the seam and over arcs transverse to the seam. A slot may thus be produced in the seam which is wide enough for penetration of the tube and for the facilities for removal of the debris. The debris may be removed in any convenient way: by flushing with a stream of water, by suction hoses (vacuum cleaners) or by mechanical scrapers. After adequate thickness of rock has been removed from the face of the mine or excavation the corpuscular beam machine is moved up and a new cycle of fracturing is carried out. Since the corpuscular beam machine does not experience any reaction forces it can move on a relatively lightweight carriage on wheels or on caterpillar tracks.

The complete machine must necessarily be of relatively large dimensions, however, the beam itself can be thrown over very large distances while maintained in a narrow evacuated tube. It is possible to fire an electron beam for example through an evacuated tube 20 to 100 feet long, with a diameter of only a few inches. To guide the beam in the center of this tube and to keep it focused (narrow) magnetic lenses and deflection systems and beam responsive apparatus to control the lenses and deflection system are needed along the tube, but the overall size of this system can be kept below a height of about 10 inches and a width of about 20 inches. If the corpuscular beam mining machine is equipped with such a long boom, just 10 inches high, narrow slots can be cut out of the rock to appreciable depths. This is particularly advantageous in mining where the ore may be found in narrow layers embedded in the bedrock. In the excavation for instance of a tunnel 20 feet or more in diameter, the long narrow beam tube has the advantage that the machinery for removal of the debris, usually called the mucking equipment, can be brought close to the tunnel face, leaving only a narrow passage for the beam tube. Besides the tunnel face can readily be inspected.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, both as to its organization and as to its method of operation, together with additional objects and advantages thereof, reference is made to the following description taken in connection with the accompanying drawings, in which:

FIGS. 1 and 2 are a view in side elevation and a plan view respectively showing the vehicle with the corpuscular-beam generator used in the practice of this invention;

FIGS. 3 and 4 are views generally diagrammatically showing the control for maintaining the long corpuscular beam aligned; and,

FIG. 5 is a view in side elevation of an electron beam generator uniquely applicable to the practice of this invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 through 4 show mining or excavating apparatus for operating in a narrow seam in rocky terrain. This apparatus includes an assembly of a vehicle 35, a generator 37 and control mechanism. The vehicle 35 may be a track-vehicle as shown in FIGS. 1 and 2. The vehicle 35 carries the electron-beam generator 37 and is provided with the necessary control.

The vehicle 35 includes a rotatable turret 39 which carries the generator 37. The vehicle 35 also includes a cabinet 41 which distributes power to the vehicle and its compenents, and to the generator 37 and its component. The cabinet 41 receives power and also electrical control commands through a cable 43. The cable 43 may be several miles long and is connected at its remote end to a power-supply and control assembly which includes a console for an operator who controls the operation of the apparatus. Alternatively the controls or a duplicate set of them can be provided in a control booth 900, in which the operator may ride. The power supply may also be a nuclear or radio-active generator near the vehicle with the control affected remotely. The turret 39 includes a drive 49 which can be commanded from the remote console (not shown) to rotate the turret over large angle of the order of 360.degree. about the axis 51 of the turret and over adequate angles transversely to the horizontal plane which is at right angles to the vertical axis 51 of the turret.

The generator 37, as far as its beam generating facilities are concerned, may be of the type disclosed in the above listed applications. This generator 37 differs from those of the applications in that it includes a long tube 55 through which the electron beam is guided. The tube may be 20 to 100 feet long and the beam is emitted from the end of the tube. The beam is preferably a high-power beam, for example from 150 KV and 0.05A to 1MV and 1A and higher voltages and/or currents may be used. It may be a D.C. or a pulsed beam.

Provisions are made as shown in FIGS. 3 and 4, for maintaining the beam E aligned along the tube 55. As shown in FIG. 3 the generator 37 includes an enclosure 57 which is evacuated to a low pressure and within which a source 59 of electrons is provided. The electrons are accelerated and focused into the beam E by an anode 61 and focusing cap 62 and passed into tube 55 which is also evacuated. The beam E is focused by coil 63 and passed through a series of transversely arranged chamber wall members. One of the wall members including an aperture 65 near the exit end of the beam tube and which member may be comprised of copper or tungsten. To the extent that the beam E may be misaligned as it reaches the aperture 65, it impinges on the metal of the member at one side or the other of the axis of the aperture 65, thereby generating X-rays. The X-rays are detected through collimator apertures 67 and 69 on one or the other side of the axis of aperture 65 and produce signals in an associated X-ray responsive means 71 or 73 which in turn set a control 75. The control, triggered by either 71 or 73, acts on refocusing coil 77 and deflecting coil 79 to realign and/or refocus the beam so that it passes through the center of aperture 65 and aperture 81 in the other chamber wall member with minimal current and consequently minimal impingement of the electrons on the wall of the members having these aperatures. A plurality of misalignment detectors and refocusing coils may be disposed along a long tube 55. Electrostatic deflection and/or mechanical alignment devices (not shown) may also be used in addition or instead of the above-mentioned magnetic means. Essentially the electron beam is under no electrical field in the tube 55 and this tube may be regarded as a drift tube.

The generator 37 is provided with a plurality of evacuating channels 85, 87, 89 connected to adequate pumping equipment 91 in the turret 39. Alternatively, as shown in FIG. 5, a plurality of auxiliary pumps 93, 95, 97 for example Roots-pumps, may be connected to the channels 85, 87, 89, feeding the exhaust at a substantial pressure through a long tube 99 of relatively small cross section. The tube 99 at its remote end, is exhausted to the atmosphere by a suitable pump 101.

Television cameras 104 and 105 (FIG. 1), connected in closed circuits with one or several viewers at the remote console, are mounted at the end of tube 35 and on the turret 39. In addition a spectral analyzer (not shown) for visable light and/or X-rays may be mounted on or near the end of the tube 35. This analyzer feeds back data as to the character of the light and X-rays generated by the beam E to the remote console. From these light or X-ray spectra the ore-bearing and other properties of the rock 33 can be determined.

Debris removal apparatus (not shown) controlled from the turret 39 may also be provided in the seam 31.

Typically the generator 37 may have a 20 ft. long tube 55 which has a diameter of less than 10 inches; duct 89 may have the same or a smaller diameter. This long-nosed generator 35 could cut a 20 inches slot into the rock 33 to a depth of about 18 ft. without any need to widen this slot. The generator 37 proper with power supply and other parts can move on a vehicle 35 in a passage 4 ft. wide .times. 5 ft. high. The slot 31 excavated by the beam E is of adequate cross-sectional area to accommodate the beam tube.

Since the beam E cuts force-free, no accurate track is needed for generator positioning; a caterpillar carriage 35 moving over the rough rock surface is adequate. The actual positioning of the tube 35 to the spot which is to be pierced, or to a line along which a melt-cut is to be made, is controlled by a sensor (closed circuit TV) and servocontrol system which swings the generator 37 (with or without the long-nose tube 55) but not the vehicle 35.

Depending upon the kind of rock the cut may be shallow but fast, or deeper and slower. The different size of the debris requires different removal systems. The cost of those systems affects the economics more than the actual energy expenditure in the cutting process (which is higher for shallow cutting). If a spalling type of rock were present high speed beam E movements (for example, 200 inch/minute at moderate beam power would remove layers 1/4 inch at a time).

While preferred embodiments of this invention have been disclosed herein, many modifications thereof are feasible. This invention then is not to be restricted except insofar as is necessitated by the spirit of the prior art.

Claims

I claim:

1. Apparatus for aligning a beam of charged particles with a section of an elongated passageway provided with a transverse wall having a beam aperture through which said beam passes, said wall being effective to emit X-rays when impinged by said charged particles, said beam alignment apparatus comprising: a set of X-ray detectors with collimators, said collimators being so aligned as to pass X-rays only if they come from certain portions of said wall with which said collimators are aligned, and signal processing means which compares the signals from the various X-ray detectors to ascertain which edge portion of the beam aperture is impinged by an excessive amount of said charged particles and therefore emitting an excessive amount of X-rays, and beam deflecting means responding to said signal processing means so as to equalize the signal strength received by all of said X-ray detectors thereby to align said beam in said aperture.

2. Beam alignment apparatus according to claim 1 including means for determining the total X-ray intensity received from all of said X-ray detectors, and beam focusing means responsive to the total X-ray intensity so as to minimize the total X-ray intensity thereby passing the greatest part of said beam through said beam aperture.

3. The method of realigning a beam of charged particles said beam being produced by a beam generator having an elongated hollow structure provided with a transverse wall having an aperture therethrough, said wall adjacent said aperture being effective to emit X-rays when impinged by said charged particles, said beam generally being aligned to pass longitudinally through said structure, the said method comprising controlling the path of said beam of charged particles through said aperture by sensing the X-rays emitted from said wall when said charged particles impinge on selected portions of said wall and adjusting the path of said beam of charged particles to minimize the magnitude of said X-rays thereby centering said beam of charged particles in said aperture.

4. A charged particle beam generator comprising a body member having an evacuated chamber and a passageway leading from said chamber outwardly of said body member, means in said chamber generating and projecting a beam of charged particles through said passageway, a chamber wall member in said passageway, said wall member being provided with first and second wall surfaces spaced longitudinally along the path of said beam of particles, said wall member having an aperture extending between and opening outwardly of said first and second wall surfaces, said first wall surface being on the side of said wall member toward said generating means and effective to emit X-rays as a consequence of the impingement thereon of said charged particles, beam adjusting means adjacent said beam of particles and actuatable to alter the path of said beam of particles, X-ray responsive means, X-ray selecting means selectively transmitting certain of said X-rays produced by a first portion of said first wall surface to said X-ray responsive means and preventing transmission of X-rays produced by other portions of said first wall surface from reaching said X-ray responsive means, and control means operatively connecting said X-ray responsive means with said beam adjusting means, said control means being effective actuate said beam adjusting means to alter the path of said beam of particles in a direction to minimize the magnitude of said X-rays which are received by said X-ray responsive means.

5. The combination of claim 4 including a plurality of said X-ray responsive means and a plurality of said X-ray selecting means individually associated with said X-ray responsive means, said X-ray selecting means selectively transmitting certain of said X-rays produced by individual portions of said first wall surface, said X-ray responsive means being coupled to said control means, said control means being effective to actuate said beam adjusting means in response to a change in the magnitude of the X-rays produced by said individual portions of said first wall surface to alter the path of said beam of particles to minimize the magnitude of X-rays received from said individual portions of said first wall and thereby center the path of said beam of particles in said aperture.

6. The combination of claim 4 in which said beam adjusting means alters the path of said beam by changing the direction of said path of said beam relative to said aperture.

7. The combination of claim 4 in which said beam adjusting means alters the path of said beam by focussing said beam of charged particles relative to said aperture.

8. The combination of claim 4 in which said beam adjusting means alters the path of said beam by focussing and changing the direction of said beam to minimize the total magnitude of said charged particles which impinge on said individual portions of said first wall.

9. The combination of claim 4 in which said X-ray selecting means is a collimator located in said passageway adjacent said first wall surface, said collimator having a passageway therethrough and positioned between said first portion of said first wall surface and said X-ray responsive means.