US2308517A

US2308517A - Method of and apparatus for mining

Info

Publication number: US2308517A
Application number: US373504A
Authority: US
Inventors: Karl L Konnerth
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-01-07
Filing date: 1941-01-07
Publication date: 1943-01-19
Anticipated expiration: 1960-01-19

Description

Jan. 19, 1943.

K. L. KONNERTH METHOD OF AND APPARATUS FOR MINING Filed Jan. 7, 1941 7 Sheets-Sheet l Ina/ 72102? K464 A. /K0/v EETH,

Ja 19, 1943. K. KONNERTH METHOD OF AND APPARATUS FOR MINING '7 Sheets-Sheet 2 Filed Jan. 7, 1941 [menial '2' K464 A. av/v5? Jan. 19, 1943. K. L. KONNERTH METHOD'OF AND APPARATUS FOR MINING 7 Sheets-sheaf. 5

Filed Jan. 7, 1941 Jan. 19, 1943. K. L. KONNERTH A METHOD OF AND APPARATUS FOR MINING Filed Jan. 7, 1.941 7 Sheets-Sheet 4 Jan. 19, 1943. K: KONNERTH 2,308,517

METHOD OF AND APPARATUS FOR MINING Filed Jan. 7, 1941 7 Sheets-Sheet 5 Jan. 19, 1943. K. L. K'ONNERTH 2,303,517

METHOD OF AND APPARATUS FOR MINING Filed Jan. 7, 1941 '7 Sheets-Sheet 6 ,25 ,wi 49. figffi ifi jii I Jan. 19, 1943. L KONNERTH 2,308,517

METHOD OF AND APPARATUS FOR MINING Filed Jan. 7, 1941 7 Sheets-Sheet 7 K424 A. Kawvaenv,

Patented Jan. 19, 1943 METHOD OF AND APPARATUS FOR G Karl 1.. Konnei'th, Uniontown, Pa. Application January 1, 1941, Serial No. 313,504

s Claims.

The present invention relates to mining machines and a method of fracturing and removing coal and the like, this application being a continuation in part of my prior application, filed November 17, 1937, Serial No. 175,118.

It is a prime object of this invention to provide a method of mining which fractures and separates coal or other material from its natural bed by the use of forced vibration, whereby to mine the coal or other material in a highly efilcient manner and with greatly increased production in comparison with the commonly employed methods, of drilling, picking or blasting.

My invention contemplates the conjoint app ication of pressure and a source of vibration to the coal bed in such a manner as to define a vibrationresponsive mass of the coal and to vibrate said mass at substantially its resonance frequency, to thereby fracture and separate said coal mass from the bed. By forced vibration of the responsive mass to substantially its resonance frequency, the resulting amplified total vibration results in the fracturing and separation of sufllcient coal volume adjacent the coal faceas to aflord a hi hly successful, speedy and efficient method of mining.

A further object of my invention is to provide improved apparatus for carrying out the said method.

Still further objects are to provide an apparatus for the purposes stated by which a suitable pressure may be applied to the coal bed together with' the application of a vibratory force thereto; to provide an apparatus which will have suficient mobility and adjustability to engage and attack the coal bed over a substantial area thereof; and to provide an apparatus which is highly eilicient and durable, and one which may be readily operated in the restricted space usually encountered in mining operations.

Additional objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, wherein;

Figur l is a top plan of a mining machine constructed in accordance with the present invention;

Figure 2 is a side elevation of the machine shown in Figure 1;

Figure 3 is a side elevation similar to Figure 2 showing the machine elevated from the mine Figure 4 is a detailed sectional elevation on the line IVIV of Figure 1;

Figure 5 is a plan, partly in section, of the drive mechanism for the present invention;

Figure 6 is a section on the line VI-VI of Figure 5:

Figure 7 is an enlarged detailed elevation of the driving mechanism for the kerf cutter chain;

Figure 8 is a detailed side elevation of one of the guides and showing its pivotal connections to the frame carrying the hammers;

Figure 9 is a section on the line DI-IX of Fi Figure 10 is a section on the line X-X Figure 8;

Figure 11 is a diagrammatic showing of a method of advancing the machine to the face of the wall of the coal;

Figure 12 is a similar view, showing the machine advancing through the wall of coal;

ure 13 is an enlarged view of one of the hammers of Figure 1, broken away to show the interior thereof; and

Figure 14 is a diagrammatic view of the vibrating system employed in my invention.

In the drawings, the numeral 2 represents the main framework of the mining machine upon which the operating parts, to be hereinafter described, are mounted. An auxiliary frame 3 is positioned and arranged at the forward end of said main frame 2 and is provided, upon each side, with guideways 4 within which are positioned guides 5 adapted for vertical movement. These guides are provided with a plurality of openings 6 (Figure 8) through which bolts 1 pass and eng ge said guideways, to securely hold said guides in their adjusted vertical position.

A tool-supporting carriage 8 is pivotally connected, at one end, to each of said guides 5, and has pivotally connected on each side thereof rods 9 provided with pistons l0 operating within cylinders I! having an opening [4 for receiving a source of pressure supply through a flexible pipe got shown) extending from a valve control box An auxiliary frame It is positioned on top of said tool-supporting carriage and pivoted thereto at H to permit said auxiliary frame to be moved in a horizontal plane transversely across the wall of the mass of coal to be mined.

The tool-supporting carriagefl is provided with extensions l8, on each side thereof, to which are pivotally supported, for horizontal movement, cylinders l9 adapted to receive the pistons 20 (Figure 8) carried by the piston rods 2|. The ends of the piston rods 2| are provided with an eye for pivotally connecting the same with the extensions 22 on the auxiliary frame I6. Each of the cylinders I9 is provided with an opening 23 to receive. a flexible pipe (not shown) extending from the valve control box ill for supplying pressure to the cylinders for controlling the transverse movement of the auxiliary frame IS in a horizontal plane across the wall of the mass of coal to be mined. The auxiliary frame I6 is provided with inwardly-extending flanges 24 and spaced from the bottom of the auxiliary frame IE to form guideways within which is adapted to advance or retract, a hammer-carrying carriage connection of any conventional construction (notshown) extending from the valve control box I! for supplying pressure thereto for operating the piston thereof. 7} The end of the piston rod is pivotally connected at 30 to an upwardly-extending flange or lug 3! on the forward end of the hammer-carrying carriage.

Secured to the hammer-carrying carriage 25, in any desired manner, are one or more hammer-operating mechanisms 55', within each of which is positioned a free-moving piston a. Located within the nose of each hammer-operating mechanism 55' is the shank of a preferably blunt dislodging tool 55, so positioned and arranged within the hammer-operating mechanism as to be operated on by blows from said free-moving piston repeated at a rate from 1000 to 2000 blows per minute. For example, the hammers 55' may be electrically operated, to reciprocate their freemoving pistons 11' forwardly and 'backwardly at high veloc ty. Each piston strikes directly on the shank of its dislodging tool 55 on the forward stroke and against a Spring back stop I) on the backward stroke, the said hammers being operated in synchronism. 4

Each dislodging tool 55 is provided with an integral collar c'enclosed within the hammer device, the' rear face of said collar being engaged bv a bushing d fixed in the hammer structure. wherebythe forward pressure of the piston of hydraulic cylinder 28 upon said structure is transmitted directly to the tool 55, urging the same against the coal face and maintaining contact therewith during operation. A spring e is preferably provided at the forward end of the hammer for coaction with its piston to reciprocate the tool without injury thereto, when the latter is free of the coal face.

Pivotally secured at 32 to a frame 33, on each side of the machine, are shoes or members 34 having an arcuate surface-engaging face 35. Pivotally connected at 38 to the forward end of each shoe 34 is a cyl nder provided with an opening for receiving a pipe (not shown) extending from the control valve box iii. A piston is operable within the cylinder 31 and is pivotally connected, at 39, to the forward end of the auxiliary frame 3. v Y

Secured to the main frame 2 and extending forwardly of the machine is a breast cutter frame 40 around which the endless cutting chain ll moves for cutting a kerf in the mass of coal at the bottom thereof, as shown in Figure 2 of the drawings. An endless receiving conveyer 42 is positioned and arranged within the breast cutter frame 40 and extends upwardly in an inclined position through the auxiliary frame 3 to discharge coal received thereon to the discharge conveyer 43 which leads back to the mine car.

Mounted on the auxiliary frame 3, or in any convenient location, is a control valve box I! having control valves ll, 45, I8 and 41, either manually or automatically controlled, as desired. Extending from the control box I! is a pipe 48 leading to a suitable source of fluid pressure supply (not shown). Extending from the control valve box II are pipes ii, 62, SI, and 54 connected, by flexible tubes or the like, to the respective openings in the cylinders i2, i9, 28 and 31, whereby fluid pressure may be selectively applied to the respective cylinders for eflecting a vertical movement of the tool-supporting carriage, an oscillating movement of the auxiliary frame l8. a movement of the shoes 34 or a forward or rearward movement to the hammer-carrying carriage 2B. A suitable motor, indicated at M, rotates a bevel gear 58. This gear 58 is in mesh with a bevel gear 58'. A bevel gear 58 is keyed to said gear 58 and adapted to revolve on a sleeve 59 mounted loosely on a reduced portion of a shaft 80. Positioned on said sleeve 58 is an element 5| forming a part of a clutch, the other element of which is designated at 62. The element 8| of the clutch and gear 58 are keyed together on the sleeve 59, while the clutch element 62 is keyed to the lower portion of the shaft 60. Mounted upon the lower end of said shaft 60 is a sprocket for driving the endless cutting chain 4|. Upon rotation of the motor; the gears 56' and I8 revolve with the sleeve 59 on the reduced portion of the shaft and, upon the throwing-in of the clutch element 82 to engage the clutch element 8|, rotation of the shaft 60 is eflected for driving the cutter chain ll. A bevel gear 83 is secured to a sleeve 83 on one end thereof while one element of a clutch 84* is secured on the opposite end of said sleeve. A shaft 64 extends within said sleeve and has secured to one end the sprocket wheel of the chain and sprocket assembly 69. A second element of the clutch B4" is splined to said shaft N for slidable movement thereon to engage and disengage the elements of said clutch 84* to impart rotary motion to said shaft N. of the chain and sprocket arrangement 69 and carries on one end thereof a gear 1| adapted to mesh with the gear I2 (Figure 1), while on the opposite end of said shaft there is mounted a chain and sprocket arrangement I3 connected to a normally opened clutch member H for transmitting movement to a shaft 15 having a worm l6 thereon for engaging the worm wheel 11 which controls the horizontal movement, in a transverse plane, of the discharge conveyer mechanism 43..

A shaft 18 is keyed to the gear 12 and is provided with a bevel gear I. (Figure 5) adapted to mesh with the gear 80. Sprocket wheels 8| are carried by the shaft 18 for imparting movement to the conveyer chain for operating the conveyer 42, while a sprocket 82 (Figures 2 and 5) is adapted to rotate a chain and sprocket arrangement 83 (Figures 1 and 5) for driving the endless conveyer. Mounted upon the shaft 18, in

any conventional manner, is a plate clutch 84 having a clutch release sprocket drive 85 extendthe shaft 18 to start or stop the

conveyers

42 and 43.

The clutch I should preferably be of a disc A shaft 10 is rotated upon movement clutch construction, so that in case of obstructions, such as too large lumps of coal or

conveyers

42 or 43 becoming fast in any way, provision is made for slippage of the drive-in clutch 84 to prevent mechanical injury.

The machine receives its electrical power through a suitable trailing cable connected in the conventional manner to the mine circuit at the most suitable point.

The operation of the machine is as follows:

Mounted in any conventional manner upon the main frame of the mining machine is a rope friction feed drum ill driven from the motor through any conventional connection to advance or retract the mining machine in its mining operation, as shown in Figures 11 and 12.

Suitable anchor jacks 89 are provided to receive the cables 88 from the drums 81 so that as the rope or cable drums 8'! rotate, the cables 88 are simultaneously wound on said drums, thereby advancing the entire machine longitudinally towards the mass of coal until the cutter chain ll engages the wall of the coal, as diagrammatically shown in Figure 11. The direction of movement of the machine is controllable by relocation of the anchoring Jacks and operating either or both of the rope drums 81. a

The operator occupies a position most advantageous to readily control the several valves in the control box l in. order to operate the various mechanisms hereinabove described and, as shown in Figure 11, as soon as the machine has been positioned adjacent the wall to be mined, the motor, which rotates the

gear wheels

58, 56 and 58, is started and, upon throwing in the clutch Si, 62 (Figure 6) the shaft is caused to rotate the endless cutter chain 4| during the operation of the rope drum feeding mechanism, to cut a her! in the lower portion of the mass of coal as shown in Figure 2.

The

dislodging tools

55, 55 remain in parallelism as shown in Figure 1 in full lines, and are forcibly coupled with the solid mass of the mine vein by the hydraulic motor 28. The various positions of the

tools

55, 55 are controlled by supplying pressure to the cylinders I0 so as to elevate the tool-supporting carriage 8 to the required vertical height.

ume of coal has mass and elasticity, and by continuously defining said mass through maintaining the stress thereon, it is capable of. being vibrated in resonance when excited by forced suecessive similar vibrations in the same direction.

Coal in its native bed, although not strictly homogeneous from a microscopic point of view, is

a continuous elastic media which reacts to exter- 1 nal forces as do solid bodies, such as quartz, rock, steel, etc.

The pressure application of the tools against the coal face continuously stresses the coal bed in the region thereof, and the volume of the coal so stressed, responds to and assumes the mode of the applied forced vibration. Since the period of the applied forced vibration approaches the value of the free or natural period of the region constituting the responsive mass of coal, the phenomenon known as resonance is produced. Be-- S represents the elasticity or spring property of Before the dislodging tools are forced into contact with the mass of coal in its native bed, the motor l0 may be operated toadjust the tool-carrying carriage 8 vertically, together with the guides 5, due to its pivotal connection therewith at 5'. After the guides have been moved vertically to elevate the tool-carrying carriage to its proper vertical position, it is held in its adjusted position by the bolts 1. (Figure 8.) After the kerf has been cut or during the cutting thereof, the tools may be adjusted on the upright pivot l1 to one 'of the dotted line positions shown in Figure 1, while the tools remain in parallelism with the cylinder 28. The preferred starting position is shown at A in dotted lines in Figure 2.

With the tools 55 so positioned, they are subjected to a substantial initial pressure by means of cylinder 28 continuously urging said tools against the coal face, said pressure being sumcient to maintain the tools in contact with said coal during the forced vibration thereof by means of their synchronous hammers 55.

The pressure application of the tools against the coal face continuously stresses the coal bed said coal, and M2 is the mass of the machine plus that of the surrounding earth, coal, etc. The tool 55 engages the coal mass Mi under the continuously applied pressure represented by the arrow P, and is acted upon by the impressed vibration of the hammer, as indicated by the arrow V. The dash pot D represents the internal friction or damping effect of the coal in its bed.

As such a system approaches resonance frequency, the cumulative eflect of the forced vibration and the resilient motion of the coal volume .will have an increased amplitude which quickly and effectively separates the coal from its native bed. The combined eflect of the applied pressure and the vibration exceeds the internal strength or cohesive property of the coal, causing the coal to fracture and become dislodged. In actual practice, the fracture and separation of the coal occurs with great rapidity and throughout a very substantial area laterally about the locus of application of the machine to the coal plied vibration of the hammers. The said volface. i r

I'have found that the coal immediately adjacent the face of the vein being attacked and above the kerf, separates and comes down freely due to the ability thereof to fall free and not interlock and become suspended. I have also observed that the vibration has likewise fractured the inner coal, and that while the same tends to lock itself in place or hang, particularly such coal as is inwardly beyond the extent of the kerf, such coal is readily dislodged after the removal of the coal in front thereof. Such a far reaching action into the coal bed evidences the amplitude of the vibration attained, and since the impressed forced vibration is of relatively low amplitude, the results clearly indicate that the system has produced a cumulative action such as is only attained through resonance.

Repeated tests have determined that such resonance occurs withan applied frequency of from 1000 to 2000 vibrations per minute, with best results for mining ,coal of the character structure by reason of contained slate and otherforeign matter, but the stated range of frequencies appears to permit satisfactory operation for all practical purposes.

While the tools 55, 50 enter the coal vein or bed during operation, it is to be particularly noted that they do so only by reason of following up and maintaining contact with the coal as and when portions of the coal are dislodged by the vibration, and virtually a new coal face is formed. Such action is accompanied by' appreciable lateral dislodgment of the coal beyond the region of contact of the tools and is clearly distinct from the usual localized penetration accompanying the action of the common reciprocating pick or drill.

The present method may be employed with a machine of the character described having a single hammer, but a spaced pair thereof is preferred due to the increased effect obtained thereby laterally of the coal bed.

As distinguished from the former devices and practices referred to, my improved method enables the transmission or impression of forced vibrations through or upon the coal, without localized penetration by the tools employed, and sets up sufficient vibration waves in the coal as to result in the extensive fracture thereof. Such shown at B and C in Figure 2, so as to ultimately break down the entire mass of coal across a transverse area. Due to the fact that the auxiliary frame It is pivotally supported at I! on the tool carriage l and adapted for oscillating movement in a horizontal plane upon pressure being applied to the cylinders Is, it is possible to break down the mass of coal across its transverse plane of the wall being mined, as shown in, dotted lines in Figure l.

Secured to the frame of the machine, in any conventional manner, are guides 80 which engage the wall of the coal, as shown in Figure 12,

action greatly exceeds and surpasses the effects and results attained by the use of the simple reciprocating tools or hammers operated at .the same frequency.

In thi connection, it will be noted that I employ a machine having substantial mass which is anchored to the earth or mine floor, thereby affording a suillciently heavy, substantially immovable abutment to enable the continuous pressure application of the tools 55 against the coal face by the cylinder 28 with sufficient magnitude as and for the purposes described. For example, the actual machine illustrated in the drawings weighs substantially fifteen tons, and the force of the tools 55 against the coal face has been employed at or about 4000 pounds with successful operation. I

As the coal is fractured and broken down it is split vertically and horizontally into small lumps with a minimum production of dust or fines, and it falls on the conveyer 42 and, due to the drive mechanism hereinabove described, the conveyer 42 carries the coal rearwardly of the fracturing operation andonto the conveyer 43 for discharge into a mine car. The vibration of the coal as described eflects dislodgement of large masses in a minimum space of time.

After the mass of coal has been dislodged below the dotted line position of the dislodging mechanism indicated at A in Figure 2, pressure is supplied, either manually or automatically, to the cylinders l0 for raising the tools to a point substantially as indicated in the full line position shown in Figure 2. The pressure by means of the motor 28 and the vibratory action are again applied to the tools 55, either manually or automatically, for breaking down or fracturing the coal between the second point of attack and the kerf, the latter having been, in effect, enlarged by the initial coal removal.

After such additional dislodgement has taken place. the tool-carrying carriage is raised again, either manually or automatically, to the positions to properly guide the machine in its forward movement and maintain said machine in its normal forward travel regardless of the tendency for sidewise movement caused by the action of the kerf cutting chain ll. Idling rollers ii are secured to the guides Oil and act to guide the rope or cables I8 as they are wound or unwound upon the drums 81. ,5

Whereas the cutter chain 4| has cut a kerf of fulhdepth in the wall of the coal mass, the forward feed may be discontinued and the driving of said cutter chain stopped by disconnecting the clutch member 62 from the complementary clutch naember 6|, which prevents rotation of the shaft 6 When it is desired to stop operation of the conveyers, the hand-wheel 88 is operated to disengage the friction plate clutch 84 and prevent rotation of the shaft 18.

When it is desired to swing the discharge conveyer 43 to one side or the other, as shown in dotted lines in Figure 1, either one of the normally open clutches Il may be brought into operation by moving the lever t8 (Figure 5) inwardly against the tension of the spring 88 to rotate the gear IT in the direction desired for ultimately swinging the conveyer l3 to its required dotted line position, as shown in Figure i.

In advancing the machine toward the mass of coal to be mined there may be certain obstructions on the floor of the mine which may make it difficult to advance the machine in its forward direction and, if such be the case, the proper valve in the control box IE is operated to supply pressure to the cylinders 31 whereby the shoes 34 are projected downwardly beyond the normal plane of the main frame of the machine to a position as shown in Figure 3 of the drawings. This operation elevates the forward end of the machine and overcomes any obstruction or depression which might require the proper leveling of the machine for cutting the kerf. The main advantage of the adjusting shoes 34 i to tilt the kerf cutter on the shoes 34' as a fulcrum to adjust the plane of the kerf to be cut at the bottom of the mine vein.

Under the present invention, there has been disclosed a machine and novel method for mining coal by being able to successfully break down or fracture a mass of coal, particularly the mass between the point of pressure and the kerf. By hydraulically pressing and maintaining the tools against the coal in its native bed and vibrating the system by reciprocating the pistons at a range of frequency between one thousand and two thousand vibrations per minute, successful fracturing of the coal over a large area in a minimum space of time is accomplished. With a frequency less than the stated limits, no appreciable effect is produced on the coal, and with a frequency above two thousand blows per minute there re- I suits a straight drilling action.

Within a certain latitude the pressure exerted on the tools by the hydraulic motor 20 and the rate of vibration exerted by the electrically operated hammers should be proportioned to the hardness of the material so as to secure a vibration in approximation to the natural or resonance period of the responsive mass of coal, avoiding either too great or too slow a vibration.

Under the present invention it is possible to continuously mine and load coal with no preparatory work, such as drilling, shooting and the like.

The dislodging tools I preferably have blunt coal-engaging ends for applying both pressure and .vibration to the coal. While the tools may be pointed, I have found pointed-tools to be generally'less efficient than the preferred blunt form. The tools may be operatedin any manner, either electrically, or hydraulically, or pneumatically, so

. long as the vibration and pressure of the tool is capable of producing the phenomenon known as resonance in the responsive mass of coal, and thereby fracture and separate the same from the bed as a result of the greatly amplified stress method of operation and apparatus designed therefor, it is to be understood that various changes in the method and in the construction of the machine may be made without departin from the scope of the invention as defined by the following claims.

I claim:

1. In a mining machine having a main frame, a carriage, guideways on said main frame, guides movable vertically in said guideways, means for vertically adjusting said guides, said carriage pivotally supported by said guides, means for moving said carriage vertically, a frame mounted on said carriage and adapted to oscillate transversely in a horizontal plane, means for oscillating said frame, vibratory dislodging tools mounted on-said frame and means for vibrating said dislodging tools at a range of frequency sufficient to fracture a mass of coal.

2. A mining machine comprisinga main frame, a carriage on said main frame, guides slidably mounted on said carriage, a frame pivotally connected to said guides, means for vertically moving said frame about its pivot, a mining tool carriage mounted on said frame, means for swinging said mine tool carriage in a horizontal plane, dislodging tools mounted on said tool carriage and means for vibrating said dislodging tools at high frequency, said vibrating means including a reciprocating piston operating upon said dislodging tools at a frequency of not less than 1000 blows per minute. i

3. A mining machine comprising a main frame, a carriage on said main frame, guides slidably mounted on said carriage, a frame pivotally connected to said guides, means for vertically moving said frame about its pivot, a mining tool carriage mounted on said frame, means for swinging said mine tool carriage in a horizontal plane, dislodging tools mounted on said tool carriage and means for vibrating said dislodging tools at high frequency, said vibrating means including a reciprocating piston operating upon said dislodging tools at a frequency of not more than 2000 blows per minute.

mounted on said carriage, a frame pivotally connected to said. guides, means for vertically moving said frame about its pivot, a mining tool carriage mounted on said frame, means for swinging said mine'tool carriage in a horizontal plane.-

dislodging tools mounted on said tool carriage and means for vibrating said dislodging tools at high frequency, said vibrating means including a reciprocating piston operating upon said dislodging tools at a frequency of not more than 2000 blows per minute and means for raising said frame, vibratory dislodging tools mounted on said frame and means for vibrating said dislodging tools at a range of frequency sufilcient to fracture a mass of coal, a breast cutting frame secured to the forward portion of said main frame, an endless cutter chain carried by said cutting frame and an endless conveyer positioned and arranged in the breast cutting frame and adapted to operate within the kerf formed by the cutting chain.

6. In a mining machine having a main frame, a carriage, 'guideways on said main frame, guides movable vertically in said guideways, means for vertically adjusting said guides, said carriage pivotally supported by said guides, means for moving said carriage vertically, a frame mounted on said carriage and adapted to oscillate transversely in a horizontal plane, means for oscillating said frame, vibratory dislodging tools mounted on said frame and mean for vibrating said dislodging tools at a range of frequency sufllcient to fracture a mass of coal, a breast cutting frame secured to the forward portion of said main.

frame, an endless cutter chain carried by said cutting frame and an endless conveyer positioned and arranged in the breast cutting frame and adapted to operate within the kerf formed by the cutting chain, said breast cutting frame extending forwardly of said dislodging tools.

7. A mining machine comprising a main frame,

an auxiliary frame on said main frame, guides slidably mounted on said auxiliary frame, a carriage pivotally connected to said guides, means for vertically, moving said carriage about its pivot,

a mining tool supporting auxiliary frame mounted on said carriage, means for swinging said auxiliary frame in a horizontal plane, hammers mounted for vbratory movement on said auxiliary frame, and means for vibrating said hammers at a frequency of vibration substantially equal to the dangerous frequency of vibration of the mass of coal and not less than 1000 blows per minute.

8. The method of mining coal which consists in applying a source of vibration to a face of the coal in its native bed, vibrating said source in the range of from 1000 to 2000 vibrations per minute, and simultaneously stressing the coal by exerting sufficient pressure at the locus of application of the source of vibration to the coal face as to continuously maintain contact therebetween during suchvibration, to fracture and separate a responsive mass of coal from the bed.

. i. 7- 4. Anuningmachinecomprising amain frame, a carriage on said main frame, guides slidably 9. The method of mining coal which consists in engaging a face of the coal in its native bed with a blunt instrument, applying vibration to said instrument in the range of from substantially 1000 to 2000 vibrations per minute, and simultaneously stressing the coal by exerting sufficient pressure upon the instrument to maintain continuous contact thereof with said coal face during said vibration, to fracture and separate a responsive mass of coal from the bed.

10. The method of mining coal which consists in engaging a face of the coal in its native bed with a blunt instrument, applying vibration to said instrument at substantially 1800 vibrations per minute, and simultaneously stressing the coal by exerting sufllcient pressure upon the instrument to maintain continuous contact thereof with said coal face during said vibration, to fracture and separate a responsive mass of coal from the bed.

11. The method of mining coal which consists in initially stressing the coal in its native bed by the application of pressure to a face thereof, applying a source of vibration to said face, vibrating said source in the range of from substantially 1000 to 2000 vibrations per minute, and simultaneously exerting sufllcient pressure at the locus of application of the source of vibration to the coal face as to continuously maintain contact therebetween during -said vibration, to fracture and separate a responsive mass of coal from the' bed.

12. The method of mining coal which consists in simultaneously applying pressure and vibration to a face of the coal in its native bed, said pressure being sufilcient to maintain continuous transmission of the applied vibrations to the coal, vibrating the coal stressed by said pressure and vibration to substantially the resonance frequency thereof, whereby the magnified internal stresses generated in the coal so stressed overcome the internal cohesive strength of the coal to fracture and separate the same from the bed.

13. The method of mining coal which consists in stressing the coal in its native bed by the application of pressure to a face thereof, whereby a mass of the coal is rendered responsive to an applied vibration, applying a source of vibration conjointly with said pressure and thereby vibrating the responsive mass of coal at substantially its resonance frequency, the magnitude of said stressing pressure being at least sumcient to maintain continuous transmission of the applied vibrations to the coal.

14. The method of mining coal which consists in simultaneously applying pressure and vibration to a face of the coal in its native bed, said pressure being suflicient to maintain continuous transmission of the applied vibrations to the coal, vibrating the coal stressed by said pressure and vibration by an applied vibration of a frequency of from substantially 1000 to 2000 vibrations per minute and to substantially the resonance frequency thereof, whereby the magnified internal stresses generated in the coal so stressed overcome the internal cohesive strength of the coal to fracture and separate the same from the bed.

15. The method of mining coal which consists in cutting a kerf in a coal bed, simultaneously applying pressure and vibration to a face of the coal adjacent the kerf, said pressure being sufficient to maintain continuous transmission of the applied vibrations to the coal, vibrating the coal stressed by said pressure and vibration to sub stantially the resonance frequency thereof, whereby the magnified internal stresses generated in the coal so stressed overcome the internal cohesive strength of the coal to fracture and separate the same from the bed. a

16. The method of mining coal which consists in cutting a kerf in a coal bed, applying a source of vibration to a face of the coal adjacent the kerf, vibrating said source in the range of from 1000 to 2000 vibrations per minute, and simultaneously stressing in the coal by exerting sufficient pressure at the locus of application of the source of vibration to the coal face as to continuously maintain contact therebetween during such vibration, to fracture and separate a responsive mass of coal from the bed.

KARL L. KONNERTH.