US1330743A - Apparatus for mining roof-props - Google Patents

Description

E. C. MORGAN.

APPARATUS FOR MINING ROOF PROPS.

APPLICATION FILED JULY 5. 1917.

Patented Feb. 10, 1920.

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E. c. MORGAN. APPARATUS FOR MINING ROOF PROPS.

' APPLICATION FILED JULY 5.1917- 1,330,743. Patented Feb. 10,1920.

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a I I II/I/ I E. C. MORGAN.

APPARATUS FOR MINDNG ROOF PROPS,

I917 Patented Feb. 10, 1920,

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E. C. MORGAN. APPARATUS/FOR MINING ROOF PROPS. APPLICATION man JULY 5.1911;

1,330,743; Patented Feb. 10, 1920.

. 5 SHEETSSHEET 4- E. C. MORGAN.

APPARATUS FOR MINING ROOF PROPS.

APPLICATION FILED JULY 5.1911.

5 vwewto'c Edmund Ullozy m Hi i m EDMUND MORGAN, F NEW R arranaros FOR MINING 'noor-rnors.

Original application filed Junev 7, 1912, Serial No. 762,373,

Specification of Letters Patent.

Patented Feb. 10, 1920'.

Divided andthis application filed July 5, 1917.

Serial No. 178,766.

county of Queens and State ofNew York,

haveinvcnted certain new and useful Improvements in Apparatus for Mining Roof- Props, of which the following is a specification.

The present application is adivision of my copending application Serial No. 702,373, filed June 7, 19.12, for an improvement in a method of mining.

My invention relates to apparatus for dislodging a mass of material from its native bed in a mine chamber, and one of the objects of my invention is the provision of apparatus for dislodging masses of material of predetermined shape and height so that theycan be used in a mine chamber as roof props.

More particularly itis the object of the present invention to provide mechan sm for cutting lrerfs about a mass of material 111 the roof or floor of a mine chamber to form a am of material which can easily be n cits-o as to have a height QPPI'OXlequal to the distance between the androof of tie mine chamber, to permit the frustum to be used as a roof'prop spaced from the place of dislodgment.

(Ether objects of the invention will appear hereinafter, the novel. features and combinations of elements being set forth in the apbros.

. pended claims.

In the accompanying drawings Figure 1 is a plan view of a machine for cutting conical kerfs in the roof of a mine chamber Fig. 2 is a sec ional elevational view taken on the lines A-l3 and EF of Fig. 1;

Fig. 3, is a sectional elevational view on the line NO of Fig. 1 looking in the direction of the arrow;

Fig. 4: is a plan view of a modified machine for cutting kerfs to form tapering sections or frustums of pyramids or of paralleiopipedons Fig. 5 an elevational view of the kerfcutting mechanism used in the machine shown in plan in Fig. 4;;

Fig. 6 is an enlarged elevation of the cutters shown at the lower end of Fig. 4; Fig. 6 is also a view in elevation from the lefthand side of Fig. 5;

Figs. 7, 8, 9 and 10 illustrate diagrammatically the operation of the cutting mechanism shown in Figs. 4, 5, and 6;

Fig. 11 illustrates the application of the machineshown in Figs. 1 and 2 to the roof of a mine chamber;

Fig. 12 illustrates a. method of dislodging frustums of cones from the hard floor of a mine chamber by means of a machine simi lar to that shown in Figs. 1 and 2; v

Fig. 13, illustrates the method of using the machine shown in Figs. 1 and 2 to dislodge a frustum-of a cone from the roof of an inclined mine chamber;

F 14 illustrates a method of using-the machine shown in Figs. 1 and 2 to form a series of double arched supports between the floor and the roof of a mine chamber;

Figs. 15, 16 and 1? illustrate different shaped frustums which may be dislodged into a mine chamber and used as roof props therein;

Fig. 18illustrates diagrammatically mech anism for shifting the dislodged frustums to new locations in the mine chamber where they are to act as roof props, and also mechanism for lifting the floor frustums into the mine chamber, and mechanism for moving the kerf-cutting machine to new locations in the mine chamber.

Fig. 19 is a view similar to Fig. 18 but more complete F ig. .20 isan elevational view of the hoisting mechanism shown in Fig. 19;

Fig. 21 is an enlarged View showing the mechanism for connecting a draft rope to a tapered section of dislodged material;

Fig. 2:2 is a sectional elevation of the pumping mechanism for operating one of the lifting arms; and

Fig. 23 is an enlarged sectional elevation of the right hand portion of Fig. 2 but more clearly illustrating one of the individual drilling machines.

Coal mining in many sections is carried on very ineliiciently because only the best coal and that most easily removed is usually mined. The methods of mining usually pursued result in the distortion and ruin of veins of coal above the places where mining operations are being carried on and also the loss of much of the coal in the vein being worked. A preferable method of mining is by the long wall system by which all of the mineral is removed as the mining progresses, but owing to the diffiwhy and expense of holding up the roof only a small percentage of coal mining in this country is carried on by that system, and even where it is practicable it often has the objection of disturbing the veins of mineral in overlying strata and of disturbing the land at the surface, tending to render it useless for farming purposes.-

Owing to the difficulty of holding up the roof nearly all of the coal mining in this country is now carried on by what is known as the room and pillar system, which, in most cases, is very wasteful of the coal in the vein being worked, destructive to the veins in the overlying strata and to the land at the surface; in addition, a large amount of timbering is required to support the roof of the mine chamber a suflicient length of time to enable the mining of the coal therein. In the aggregate a vast forest of timber is disappearing into the mines yearly and furthermore the fatalities which occur every year by reason of falls from the breaking roofs, are more than from all the other causes combined, even including the terrible gas and dust explosions that occur from time to time.

By the use of my methods of supporting mine roofs hereinafter described and disclosed in the drawings, which methods can be carried on in low-roofed mine chambers as well as high-roofed mine chambers, practically all of the mineral is saved in the vein being worked, and none of the mineral in the strata above or the land at the surface, is disturbed. These methods also enable the mining to be carried on with a much greater degree of safety to the operatives than with the methods heretofore usually carried out. These methods arev de scribed and claimed in my copending applications. Ser. Nos. 187 ,7 03 and 198,746, respectively filed August 22, 1917, and October 26, 1917 both for methods of mining.

Inasmuch as one of the most important problems in metal mining as well as in coal mining, is holding up the roof while the mineral is being removed, I wish it to be understood that the apparatus herein described may have a general application for mining purposes.

The strata immediately overlying a coal vein is usually slate or sandstone which is harder and more capable of sustaining great weight than the strata immediately under lying the vein of coal, which underlying strata is usually fire clay or shale. Sometimes, however, the conditions stated are reversed and the mine chamber will have. a sandstone or limestone floor and a comparatively soft roof.

My improved method of supporting mine roofs as covered in the aforesaid co-pending applications, consists in removing wedge,

cone or pyramid shaped sections in one piece from either the roof or the floor, of a height approximately the same as the distance between the floor and the roof of the mine chamber, and placing them at points adjacent to where the sections have been removed. The shape of the sections may be predetermined and also their height before being dislodged from the mass of unmined material. The height of each section may be made suiiiciently less than the height between the floor and the roof to permit the sections to be moved freely to the point desired, making allowance for unevenness of the floor and roof. Ordinarily this is all that will be required owing to the shape of the sections. Their height can be determined before removal so that they will be practically tight when shifted into the desired positions. Slight settling of the roof may then be relied upon to form a firm bearing without causing any cracking of the roof or any appreciable disturbance above the mine chamber. However, if desired, it is entirely practicable to drive thin wedges in the slight clearance space so that heavy pressure maybe applied between the fioor and the roof against each section as soon as anchored in the desired position. It should be understood that the operator can determine just where he wants to place the section before he removes it, and, with suitable extensible measuring means, can decide just what height he wants the section to be, andowing to the wedgelike shape of each section, it can be broken off at almost exactly a predetermined point.

The number of sections necessary to be used for a given area will of course vary greatly owing to the character and weight of the overlying strata of material, the character of the material from which the sections are taken, the character of the material of the floor, etc., but it can all be predetermined with accuracy by those skilled in the art. Preferably sufficient sections should be used to hold the roof up indefinitely, so that it may be practicable to work, at any time in the future, the coal veins that may be in the overlying strata.

Referring to the drawings, Fig. 11 is a sectional view through a coal mine, including part of the roof and floor. In this case the roof is composed of much stronger material than the floor and therefore the prop sections are taken from the roof. The coneshaped section 25 is shown ready to be removed to a position similar to the section 26 which has been placed in its permanent position. Ordinarily a section such as that designated 25 will break away from the unmined mass at the line 27 owing to thefact that it is the smallest and weakest cross-section. If in some material the conical sec tion which is that designated 25, is not broken off of its own weight, a wedge or similar means may be used to :assist in breaking the conical section along the line 2?. Thin wedges 28 and 29 may be used, if desired, between the roof and the upper end of the conical section after the latter has been moved to the position where it is to be located permanently, but the space that need be left between the top of such a section as that designated 26 in Fig. 11, and the roof, may be much less in proportion than that shown in the drawings, in which the size of the wedges 28 and 29 is exaggerated for clearness in illustration.

When a section has been dislodged from the roof I prefer to let it-down slowly, but it may be allowed to drop quickly if desired, particularly where the base is rather large and the air under the same will act as a cushion. After a section such as that designated 25 in Fig. 11 has been lowered to the floor, it may be moved by any simple means, such as a winding engine of ordinary and well-known construction, as diagrammatically illustrated in Fig. 18.

In many mines none of the usual props need be regularly used, although if desired such props as those indicated at 81 may be used without interfering with the application of my invention.

In Fig. 12, which is a cross-section through a coal mine chamber having a hard floor and a comparatively soft roof, I have shown the sections being taken from the hard floor. Near an ordinary prop 1% a section has been cut and wedge 42 may be used to break off the section along-the line 18. The sections taken from the hard floor are lifted from the mine chamber and moved over to a permanent position such as. the section designated 11, which may be securely anchored in 'positionby means of the wedges 45 and 46.

In Fig. 13 I have shown my method applied to a very steep pitchingvein in which 4:? indicates a coneshaped section before removal. from the roof and 48 indicates a section in permanent position. Thin wedges 19 and 50 may be used for locking the sec tion 4:8 in place. In this case the sections, after removal, may be guided to the desired permanent position, by their own weight which will cause them to slide over the floor of the mine chamber.

Fig. 18 is a plan view showing diagrammatically a convenient arrangement for moving the dislodged sections into place after they have been lowered to the floor; also for lifting and placing the sections as they are taken from the floor; and also for moving the cutting apparatus to new locations in the mine chamber. On a suitable frame 53 is mounted a rope-winding drum 51 operated by an electric motor 52. The frame may slide on the floor of the mine and be anchored in any suitable way, as by means of the anchor 54. A boom 55 and sling rope 56 may be mounted on the frame 53, as shown in Fig. 18, and arranged to be operated by the rope 57, winding drum 51, the motor 52 and the intermediate mecha nism between the winding drum and the motor. By referring to Fig. 12 it will be seen that the sling rope 56 may be placed around the lOWer portion of the section 10 and when the winding mechanism is oper ated the boom 55 may be lifted to hoist the section 10 out of the floor, and the boom 55 may then be swung around on its pivotal connection'with the frame 53 to place the section in the position shown at 4.1 in Fig. 12.

Referring again to Fig. 18, it will be seen that the rope 57 is carried around the pulley 58 which is connected to anchor at 59. The rope 57 then extends around the pulley 60 which may be anchored by the conical prop section 61 which is already in permanent position in the mine chamber, or such pulleys 60 may be anchored by any other suitable means. The end of the rope 57 may be formed into a loop 57 and placed arount the section 63 which to be moved. Suit able clamps 64, 65 and 66 may be attached to the rope 57. These clamps may be hoo ishaped at one end to engage the lower edge of the section 58 andprevent the rope pulling to the top of the section. It should be noted that the pulley 60 is connected to the permanently located section 61 by means of a loop 60 and hooks similar to those designated 6%, 65 and 66. It should also be noted that when the sections 61 and 63 are permanently anchored in the mine chamber, or when the pulley 60 is connected to an anchor in a mine, and the end of the rope 57 is also anchored, and the anchor 54: is released, the operation of the winding mechanism may then be relied upon to shift the frame 53 and the parts thereon to a new location in the mine chamber. It should also be noted that as indicated by the dotted lines in the central portion of Fig. 18, the rope 57 may be connected to the frame 6'? of the cutting apparatus hereinafter described, to shift the latter about in the mine chamber. It should also be noted that the apparatus diagrammatically illustrated in Fig. 18 may be employed for moving sections over the mine floor so long as said sections will rest flatly thereon. This is accomplished with facility with such tapering sections as shown in Figs. 15,16 and 17 in which the flat bases are much larger than the upper surfaces. However, the mechanism shown at the lefthand portion of Fig. 18 may also be used to move inverted sections because the larger bases will then be at the roof and on account oftheir heights being approximately equal to the distance between the floor and the roof, such sections will not tip over, and

moreover the hook clamps will remain connected to the circumferential edges of the tops at the roof.

Fig. 1 1 is a diagrammatic view of a mine chamber Showing a number of sections in place. It will be noted that the air spaces left between the sections are diamond-shaped and therefore arch upwardly and downwardly; this would be the case whether the sections were taken from the roof or from the floor, thus in either case forming a structure of great strength to resist immense crushing strain from above.

I will now describe the preferred apparatus for removing cone-shaped sections from the roof or from the floor of the mine chamber. Comparing Figs. 1 and 2 it will be seen that the latter and its left-hand portion or that bounded by the lines G, H, I, J, is a sectional elevation of Fig. 1 on the line AB looking in the direction of the arrow; while the right-hand portion of Fig. 2, or that portion bounded by the lines H, I, L, K, is a sectional elevation on the line EF of Fig. 1 looking in the direction of the arrow; while that part bounded by the lines K, L, M of Fig. 2 is a sectional view on the line CD of Fig. 2 looking in tae direction of the arrow. Fig. 2 therefore brings into elevation some of the essential features of Fig. 1. Fig. 3 is a sectional elevation on the line NO of Fig. 1, looking in the direction of the arrow.

The main frame 75 of Figs. 1, 2 and 3 is in the general form of a three-quarter segment of a circle. Rotatably mounted in the main frame 7 5 by means of a suitable grooved bearing is the frame 76, which is also in the general form of the shape of about a three-quarter segment of a circle, and has suitable gear teeth 171 formed on its outer periphery. Arranged to mesh with the gear teeth 171 on the frame 7 6, are the pinions 77 and 7 8 which are secured to the shafts 79 and 80 carried in suitable bearings in the main frame 7 Secured to the shafts 79 and 80 are worm gears 81 and 82 which mesh with worms 83 and 84:, the latter being suitably secured to the shaft 85 which is mounted in bearings 86 and 87 extending from the main frame 75. An electric motor 88 mounted on the frame 75 is connected to the shaft 85 through the gears 89 and 90.

()n the frame 76 is mounted the standard 91 for supporting a reciprocating tool which may be of well-known construction, the one illustrated being operated by electric power. This reciprocating tool comprises a frame 93 on which the frame of the cutting tool is slidably mounted for feeding movement either by hand or power. The frame 93 is provided with a lateral extension 94 which is arranged for universal adjustment by means of suitable clamps connected between the extension 9 1 and the supporting standard 91, as indicated at 95. There may be a plurality of such reciprocating tools carried by the frame 75. For instance, another reciprocating tool may be mounted on the standard 96 which is similar to the standard 91. Electric current is arranged to be continuously supplied to the reciproeating tool by means of a suitable flexible connecting insulated Wire 97. This wire is electrically connected to a suitable conducting strip 98 which is mounted on the peripheral portion of the frame 76, suitable insulation intervening and extending around the frame 76 over nearly its entire length. One of the wires from the source of power may be connected to the brush 99 which is mounted on the frame 75 and insulated therefrom but in elctrical contact with the metal ring 98, which metal ring is electrically connected by the insulated wire 97 to the motor on the reciprocating tool. The other terminal of the motor may be grounded on the frame 76 and a brush 100 mounted on the frame 75 at 102 allowed to come in contact with the frame 76. The brush 100 is insulated from the frame 75, however. It will therefore be evident that a plurality of electric motors may be connected in parallel between the source of power connected to the machine at the points 101 and 102.

One of the important features of my invention is the apparatus for letting a sec tion down to the floor slowly to the dotted line position shown in Fig. 2 so that it will remain intact. Mounted on the frame 75 by means of suitable bearings 103, 10 1, 105 and 106, as shown in Fig. 1,are the crank shafts 107 and 108, at the outer ends of which are secured arms 109, 110, 111 and 112, the free outer ends of which carry rollers 118, 114:, 115 and 116 by means of suitable bearings and journals.

Each pair of arms 109, 110 and 111, 112 is operated and controlled by similar mechanism illustrated at the left-hand portion of Fig. 2. Preferably hydraulic power is used, although the mechanism may be operated by a gaseousmedium instead of a liquid medium. The framework containing the hydraulic operating cylinder pump and valves, is shown cast integrally with the frame 75. A plunger 117 in the operating cylinder is connected at its upper end to the crank shaft 108 by means of the connecting rod 118. The pump plunger 119 is operated by an eccentric cam 120 which is secured to the vertical shaft 121. To the upper end of the latter is secured a gear wheel 122 which meshes with and is driven by the gear teeth 171 on the frame 7 6. The usual pump valves are indicated at 123 and 12 1. The valve 125 controls the movement of fluid to and. from the plunger cylinder, holding the plunger or releasing it as may be desired. I wish it to/be understood that I have shown only the simplest operating apparatus for effecting movement of the pairs of arms so as to simplify the draw ings. Self-contained hydraulic pumps including plungers, valves, etc. sold on the market, may be readily applied without departing from the, spirit and scope of my invention. Y

The operation of the pumping apparatus for actuating the pairs of arms, is as follows: The. apparatus being placed in proper position, power is applied to the arms 109,110, 111 and 112,.forcing them up tightly against the roof, serving the double purpose of supporting the section to be cut and anchoring the apparatus against vibration during the cutting operations. The channelling tools arethen started and the frame 76. rotated by feeding the same around. the frame 75. This is accomplished by starting the electric motor 88' which ef fectsturning of the gears 81 and82. each in the same direction, and therefore transmits rotative power through. the pinions 77 and 78 to the large gear 171 and causes the frame 76, together with the cutting tools mountedthereon, to move in an are on the frame 75. which is held stationary. This action of feeding the. channeling tools in a circular direction willresult in the cutting out of the material. from the roof of apractically perfect coneshaped section, and by means of the adjustments shown any angle of cone desired may be obtained, and by means of suitable gages thev feeding of the channeling tools may be stopped.

It should be understoodthat the motor 88 may be operatedso as tosecure a:continuous rotary feed. of the supplemental cutting frame always in the same direction, if so desired. That isto say, the supplemental cutting frame may be rotated indefinitely about the main frame 75 constantly in the same direction through complete rotations. This is desirable when there is .a smallnum her of cutters, and enables a single cutterto cut a cone. In such event, however, the electric brushes 99v and 100 should each contact with the slip ring 98 and the same. main lead from thesource of power connectedrto both the points 101 and 102, the motor for the cutter being then groundedonthe main frame, andthe other leadfromthe source of power connectedto such main frame. Then there would be always an electrical circuit through the electric motor of; the cutting tool, although at intervals the brushes 99 and 100 would run off the slip ring on account. of the opening in the, frame 7 6.

When the desired section of the conehas been out, the pressure on the. pairs of arms 10,9, 110 and 111,. 112.. can then be eased, which will ordinarily result in the section being severed by its own weight at the weakest point which is the cross-section at its upper end, as indicated at 27 in Fig; 11. If in some material the breaking did not occur by the weight of the cone, a heavy breaking strain can be applied by releasing one pair of arms slightly and putting further pressure on the other pair of arms. If still further pressure is desired, a wedge can be applied in the channel or conical kerf at the side next to the released arms, and power can even be applied to this wedge by pulling a blunt tool on one of the channeling plungers and causing the latter to strike the wedge.

The pumping apparatus may be so arranged that when the valve 125 is closed and the pump operated, the pressure medium will be forced into thecylinder below the plunger 117 past the check valve 124. After thepump is connected to operate continuously or intermittently, the valve 125 may be opened sufliciently to cause a circulation without minimizing the pressure-on the plunger 1'17 and thereby regulating the force with which the pairs of arms are held up; As soon as the section is severed, however, the regulating valve 125 may be opened wider by the operator and the section will drop to thefioor at a speed corresponding to the degree to which the valve 125 is opened. After the rotation of the cutting apparatus is stopped, the valve 124 may keep the fluid from escaping from the cylinder below the plunger 117, and if the valve 125 is entirely closed the arms may be held up, but if' the valve 125 is opened the plunger 117 will descend and so also the pairs of arms. The diameter of the interior of the frame 75 may be such as compared withthe length of the pairs of.arms, that the arms will be free to bemoved upwardly again after the section has been lowered to the floor, as shown-in Fig. 2. The dotted arc shows the path of movement of the roller 113 in Fig. 2 and there is also shownin dotted lines at the left-hand portion of Fig. 2, the vertical position of the arm 109. VVhenthe conical section has been lowered to the floor, as indicated-by the dotted lines in Fig. 9, the apparatus-may bemoved to a new location. Inasmuch as the frames 7 5 and 76 are each provided with gaps which may register with each other when placed in proper relation, an'opening is provided for the'whole apparatus to slidepast the conical section. This is illustrateddiagrammatically in Fig. 18 by the segment of a ring designated=67. A convenient hook, as that designated 128 in Fig. 1, may be located onthe frame 75- diametrically opposite the segmental opening in the frame 75, so that the; hoisting rope'57 may be hitchedthereto as illustrated diagrammatically in Fig. 18,, or other suitablepulling means may beconnected to the hook 128 to withdraw the cutr al ting apparatus from the conical section which has been carved out from the roof and dislodged to the floor of the mine chamber. I wish to call particular attention to the fact that sometimes the roofs or floors of mines consist of material which, while strong, such as some slates, may still be most rapidly cut by rotary cutters, in which case some simple form of cutting tools, well known to those skilled in the art, may be applied in place of the percussion cutters shown in Figs. land 2, and proper feeding mechanism similar to that shown in Figs. 1 and 2, may be used to rotate the frame 76 to produce the same shaped section as that formed by the cutters shown in Figs. 1 and 2.

In Figs. 4, 5 and 6 are shown modifications for mounting cutting apparatus to enable it to cut wedge or pyramid shaped sections from the roof of the mine or from the floor, by a simple modification. 130 and 131 indicate suitable drill or percussion tool frames on which are mounted tool apparatus operated either by compressed air or electrically, and each of which may be of wellknown construction so that detailed description is deemed unnecessary. The drill frame 130 by means of a bracket 132 is pivoted to the frame 133 as shown in Figs. 5 and 6. The bracket 132 is pivoted to the frame 133 by means of a suitable pin 134, as shown in Fig. 5, and the frame 133 is pivoted on the frame 135 by means of a suitable pin 136, as shown in Fig. 6. The pins 134 and 136 are located at right angles to each other and the connections are such as to mount the cutting mechanism for universal movement on the frame 135.

An arcuate bracket 146 concentric with the pin 136 is rigidly attached to the frame 133 and slides through a lug 147 which is rigidly secured to the frame 135. By means of set screw 148 the bracket 146 may be secured to the lug 147 so as to hold the frame 133 secured to the frame 135 in definite relation thereto. This cutting apparatus mounted on the frame 135 is complete and self-contained and will operate in any position in which it is placed.

Mounted on the frame 133 is a motor 137 the framework of which by means of suitable brackets carries a crank shaft 200 which is provided with suitable bearings in the brackets. Secured to the crank shaft 200 is a worm gear 201 which meshes with and is driven by a worm 140, as shown in Fig. 5, said worm 140 being secured to the motor shaft 141. Pivotally attached to the drill frame 130 by means of a pin 142, is a bracket 143 provided with a bearing to re ceive the connecting rod 144 which is connected to the crank shaft 138. The connecting rod 144 is slidably adjustable in the bracket 143 and can be held rigidly where desired by means of a suitable set screw 145. By means of this mechanism the frame 133 may be oscillated to cause the reciprocating cutting tool to be fed back and forth at right angles to the direction of the cut into the body of the material from which the cone-shaped section is dislodged.

The drill bracket 131, shown at the lefthand portion of Fig. 6, is pivotally mounted in the frame 149 by means of a suitable bracket 150 and pin 151 as shown in Fig. 4. A bracket 152 concentric with the pin 151 is attached to the drill frame 131 and slides through a lug 1.53 on the frame 149. A set screw 154 holds the bracket 152 in such a position as desired in the lug 153. This ad justment is similar to that effected by the arc-shaped bracket 146 shown at the righthand portion of Fig. 6.

The frame 149 is slidably mounted on a rack bar 155. The frame 149 by means of a suitable bearing and a shaft 157, carries a rack pinion 158. The pinion 158 is secured to the shaft 157 and meshes with the rack bar 155. The rack pinion 158 may be suitably driven to feed the frame 149 along the rack bar by means of the feed mechanism of the drill. The drill mechanism is of the rotary type in that it is provided with mechanism for rotating the drill and also the shaft 159. A suitable extension shaft 160 provided with universal joints and an intermediate sliding connection serves to connect the drill feed to the pinion 158. The bar 155 may be made as wide as desired to assure operative angles for the universal joints. It should also be noted that intermediate the extensible shaft 160 and the shaft 139 is a crank connected to mechanism for automatically feeding the rotary drill mechanism along the frame 131. The grooved shaft 139 is provided with a worm wheel which is continuously in mesh with a worm operated by the motor which rotates the drill. It will thus be seen that the rotary drill is provided with means for automatically feeding it into the material and also along the kerf which it is making.

-The rack bar 155 may be supported at one end by a frame 161 through which it is slidable in a slot and can be held at any point desired by the set screw 163. The other end of the rack bar is carried by the brace bar 170 which has a slot therein to receive the end of the bar 155. Intermediate its ends the rack bar 155 is supported by' the frame 135 by extending through a slot in the latter. The frame 135 is somewhat similar to the frame 161 except that the frame 161 has two slots at right angles to each other, one for receiving the rack bar 155 and the other for receiving the longitudinal brace bar 162. The latter may be secured to the frame 161 by means of the set screw 164.

The longitudinal brace bar 162 is also supportedv by the frame 165 which is a duplicate of the frame 161, exceptthatit is opposite-handed. Placed parallel to the rack bar 1 55.i's an additional rack bar 166 with its rack teeth extending in the opposite direction. Oneend of'the rack bar 166 rests in the frame 165 and the other end is extended through a slot in the brace bar 170. Intermediate its ends the rack bar 166 is support ed by the frame 167 which is a duplicate of the frame 135eX-cept that the bracket or lug 168 which corresponds to the bracket 14? on the frame 135, is opposite-handed. Therack bar 166 carries a frame 169 which is a duplicate of the frame 149 on the rack bar 155.

It: will be seen that the two rack bars 155 and 166 together with the plain bar 162 and the brace bar 170 thus form an adjustable frame rectangular orsquare according to the degree of adjustment, and that provision is'mad'e for several drilling or channeling mechanisms each adjustable from a vertical cutting position to any angular cutting position desired. Feeding mechanism is also provided for efiecting the cutting of a kerf of any desireddepth in the roof of the mine chamber.

Figs. 7, 8, 9 and 10 are diagrammatic illustrations showing the methods of cutting which can be carried out by means of the apparatus shown in Figs. 4, 5 and 6.

Figs. 7 and 8 illustrate pyramid cutting while Figs. 9 and 10 illustrate the cutting of wedge-shaped sections. It should be noted that Fig. 8 represents a side diagrammatic VlGW of Fig. 7 and that Fig. 10'is a side diagrammatic view of Fig. 9. For instance, in Fig. 10 the left-hand kerf may be cut by the two cutters shown in the lower port-ion of Fig. at and the right-hand kerf of Fig. 10 may be cut. by the cutters the frames ofwhich are shown in the upper portion of Fig. a; then by hooking the pulling apparatus shown in Fig. 18 tothe perforated plate 172, the entire apparatus shown in Fig. 4- may be shifted to such a position beneath the kerfs shown in F ig. 10 that the rack bars 155 and 166 may be adjusted along the bars 162 and 170 so that the cutters on the rack bars may be operated and fed along the same to cut the diagonal kerfs shown in F 19. If'desired, however, the entire apparatus shown in Fig. 1: may be left. in the'position therein shown after the vertical kerfs shown in Fig. 10 have been made. After the cutters are mounted on the frames 161 and 165, and the bars 155 and '166 shifted along the bar 162 for. new locations of operation, of the cutters on the frames 161 and 165, the ker-fs shown in Fig. 9 may thus be cut.

The brace bar 170 is inaderemovable so that when a section 1781 has-been dislodged it may be pulled out of the frame comprising the bars 155 and 162 and 166 or such frame may be pulled away from the tapering section 178.

I wish it understood that the mechanism shown in Figs. 1 and 2 for holding, breaking and lowering the cone-shaped sections may also be used with the apparatus shown in Fig. 1 for holding, breaking and'lowering the wedge or pyramid-shaped sections. In some instances the cutters themselves may be used to support the block of coal and let it down to the floor without breaking the dislodged section. It can readily be seen by referring to Fig. 5 that the cutter could be withdrawn from the kerf and the apparatus adjusted so as to project the cutter or aspecial tool substituted therefor under the body of the cut section before the latter is broken away from the unmined mass by projecting wedges into the kerfs. cutting devices at each end of the rectangular frame shown in Fig. 4; would be sufli- Two l cient to lower a section of material having a rectangular base.

If it is desired to out conical sections in the floor of the mine chamber by means of the apparatus shown in Figs. 1 and 2, the brackets 96 and 91 are bent into the angular positions shown at 126 and 127 in Fig. 2. The cutting tools may then be directed downwardly and the feeding apparatus operated'as before, and when such floor sections are to be removed they are dislodged by means of wedges and lifted to proper position by the mechanism diagrammatically illustrated in F 18.

Tapering sections may also be cut in the floor of the mine chamber by means of the mechanism shown in Figs. 4, 5 and 6. The cutting tools are merely put on the lower sides of the rack bars instead of the upper sides and the frame suitably held in place by ceiling acks in a well known manner.

By referring to F ig. 1 of the drawings it will be seen that the bracket 172 is extended laterally from the frame 92 for holding a cutter carrier 178 having a cutter 174 at the upper end thereof. While in some instances it may be preferred to employ mechanism for reciprocating the larger cutting tool 175, it should be understood that such cutting tool maybe held rigidly against reciprocation while the rotary feed takes place. The conical feed toward the apex may or may not progress as the cutter is rotated. That is to say, the cutters 175 may make a complete rotation and then be fed to a new cutting position, or the cutters may be fed toward the apex very slowly while the same are being rotated. The cutters 175 may be operated to a certain depth, and near the apex of the cone of material being cut, the cutters 17 1 may be brought into play.- Theccutters 17 1 are preferably turned in the opposite direction from the cutters 17 5 sothat when the feed is reversed or floor of the mine chamber.

the cutters 17a may occupy an approximately radial position and be fed closer to the apex of the cone. The carriers 173 are adjustably held in the brackets 172, and after the cutters 175 have been operated to their limits. the cutters 17 4 may be extended by moving the carriers 173 radially so that additional cuts may be made near the apex of the cone to facilitate the breaking away of the cone of its. own weight, thus saving the time of breaking away of the cone by means of manually operated wedges.

It should also be noted that the rotary frame for carrying the cutting mechanism is such that it may be held stationary wherever desired and drills located in the bracket arms 91 and 96 so that holes may be drilled, several at a time if desired, into the roof The drills may be relocated in various positions until a sufficient number of holes extending toward the apex of the cone have been drilled to enable blasting charges placed near the apex to dislodge a conical mass of material along the series of drill holes extending around such mass approximately in the shape of a cone.

It should also be noted that additional terminals 17 6 and 177 may be provided on the main frame for connections from independent sources of electric power so that the electric motors for the drills or cutting tools may be operated independently of each other. If desired, the terminals 101 and 102 may be connected to one of the mains extending from the source of supply of elec tricity and the terminals 176 and 17 7 connected to the other main, thus making terminals 17 6 and 177 the frame ground returns.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of my invention as defined by the claims hereto appended. I wish, therefore, not to be restricted to the exact structure herein shown and described, but having shown the nature of my invention, and the preferred embodiment thereof, what 1 claim as new and my own invention, and desire to have secured by Letters Patent of the United States, is:

1. In apparatus for forming props in mine chambers, the combination with a supporting frame, of cutters mounted on said frame in position to operate upwardly therefrom, and means for operating said cutters including the feed thereof to cut a tapering section of material from the roof of the mine chamber and above said frame.

2. In apparatus for forming props in a mine chamber from either the roof or the floor of the mine, the combination with a supporting frame adapted to rest on the floor of the mine chamber, of cutters mounted on said frame to project upwardly when in one position and downwardly when m another position, and means for operatlng said cutters to form the faces of tapering shaped sections from the roof of the mine chamber when such cutters are projected upwardly and from the floor of said mine chamber when said cutters are projected downwardly.

3. Apparatus for forming cone-shaped sections out of solid material in its native bed in a mine, comprising a supporting frame, of cutters mounted on said frame for movement relatively thereto circularly in horizontal planes while said cutters extend upwardly from said frame, and means for operating said cutters to cause the same to form the cone-faces of said cone-shaped sections from such native bed above said frame.

1. Apparatus for forming taperingshaped sections out of solid material in its native bed in a mine, comprising a supporting frame adapted to rest on the fioor of a mine chamber, cutters mounted on said frame to extend upwardly therefrom, and means for operating said cutters including the feed thereof forwardly and laterally to describe a path conforming to the sides of said tapering-shaped sections from the mine roof above said frame.

5-. Apparatus for forming tapering shaped-sections out of the solid material of the. floor or roof of a mine, comprising a supporting frame adapted to rest on the floor of the mine chamber, cutters mounted on said frame in position to extend upwardly therefrom and in position to extend downwardly therefrom, and means for operating said cutters including simultaneous feeding thereof forwardly and laterally into the material to cause them to describe a path conforming to the shape of said tapering shaped sections to effect the dislodgment of the latter from the roof when said cutters extend upwardly and to effect the cutting of such sections when said outters extend downwardly relatively to said frame.

6. Apparatus comprising a supporting frame havlng mechanism mounted thereon for forming a section from solid material in its native bed in a mine chamber, and means mounted on said frame in position for engaging the material to hold the same in place during the operation of said cutting mechanism and until in readiness to be dislodged.

7. In apparatus for mining roof props, the combination with a supporting frame, of cutting mechanism mounted thereon, meansfor operating said cutting mechanism to cut out from the roof of a mine chamber a section of material adapted to act as a roof prop between the floor and roof of the mine chamber, and means mounted on said frame in position to hold the section of material in place during the operation of said cutting mechanism and until in readiness to be dislodged.

8. in a mining machine, the combination with a supporting frame, of apparatus mounted thereon for blocking out a section of material in its native bed in a mine, of means mounted on said frame for holding such blocked out section in place until dislodged, and mechanism mounted on said framein position for effecting the placing of said section on the floor of the mine chamber directly from its original. native position.

9. In a mining machine, the combination with a supporting frame, of apparatus mounted thereon for dislodging a block of material from the roof of a mine chamber, and power mechanism mounted onsaid frame for handlin said block of material.

after dislodgment.

10. Apparatus for forming cone-shaped sections of material from the floor or roof of a mine, comprising a supporting frame adapted to rest on the floor of a mine cham ber, a supplemental frame mounted on said supporting frame for rotary movement rel atively thereto, cutters mounted on s id suppleniental frame to extend upwardly therefrom or downwardly therefrom, means for operating said cutters including feed thereof forwardly into the material to cut a coneshaped section from the roof when said cut ters extend upwardly and to cut a coneshaped section from the iioor when said cutters extend downwardly, and means for rotating said frame together with the cutters n'ionnted thereon.

11. Apparatus for forming cone-shaped sections from the roof or floor of a mine, comprising a main supporting frame adaped to rest on the floor of mine chamber, a iplemental frame rotatably mounted on said main frame, means for rotating said supplemental frame on said main frame, cutters mounted on said supplemental frame 0 extend upwardly in position to cut a t cone-shaped section from the roof or to eX- tend downwardly in position to cut a coneshaped section from the floor, and means for operating said cutters including the forward feed thereof.

12. Apparatus for blocking out sections from the floor or roof of a mine to form roof props, comprising cutters, means for operating said cutters including the feed thereof, and mechanism comprising power-actuated and controlled arms for supporting, lifting and lowering the blocked out sections.

13. In a machine for mining roof props, the combination with a supporting frame, of cutting mechanism mounted on said frame, in position to cut into the roof of a mine chamber or in position to cut into the floor thereof, and means for operating said cutting mechanism including feed thereof to effect the dislodgment of roof props either from the roof or the floor of said mine chamber.

, 14. In a machine for mining roof props, the combination with a supporting frame, of cutting mechanism adapted to be mounted on said frame either in position to cut into the roof or in position to cut into the floor of the mine, and means for operating said cutting mechanism including the feed thereof to block out tapering sections from the floor and the roof of the mine chamber.

15. Apparatus for blocking out sections of material from the roof of a mine chamber, comprising an open frame affording free passage of the section of material from the roof to the floor of the mine chamber, cutters mounted on said frame, means for feeding saidcutters into the material in a direction in alinement with said cutters, means for feeding said cutters substantially at right angles to the first named feeding direction, and mechanism for actuating said cutters during the feed thereof into the material and along the same.

16. In mining apparatus, the combination with a supporting frame having a free and unobstructed opening therethrough for the passage of a section of material from the roof of the mine chamber to the floor thereof, of cutting mechanism mounted on said frame in position to cut a section having a diameter nearly equal to the diameter of the said opening, and means for operating said cutting mechanism to effect the cutting of a mass of material from the roof and the dis-- lodgment thereof by its own weight after at taining a height approximately equal to the distance between the floor and roof.

17. In mining apparatus, the combination With a supporting frame having an unobstructed opening therethrough for the passage of the section of material from the roof of the mine chamber to the floor thereof, of kerf cutting mechanism mounted on said frame, and means for operating said kerf cutting mechanism into the roof above said frame until the mass bounded by the kerfs is dislodged by gravity through said unobstructed opening to the floor of the mine chamber.

18. In mining apparatus, the combination with a supporting frame adapted to rest on the floor of a mine chamber and having an unobstructed circular opening extending vertically therethrough for the passage'of a mine roof section having a circular bottom, a ring rotatably mounted on said frame, cutting mechanism mounted on said ring and extending upwardly therefrom in an insaid circular opening, and means for operating said cutting mechanism lncluding rota- ,clined position toward the vertical axis of Y tion of said ring to effect the dislodgment of a tapering section of material from the mine roof into and through the circular opening of said supporting frame to the floor of the mine chamber.

19. In mining apparatus, the combination with a circular frame adapted to rest on the floor of a mine chamber in stationary position, of kerf-cutting mechanism mounted thereon and extending upwardly therefrom on an incline toward the central vertical axis of said circular frame, means for operating said kerf-cutting mechanism including; c1rcular feed thereof relatively to said frame while the latter remains stationary on the floor of the mine chamber, and means for feeding said cutting mechanism into the material to produce a connected kerf extending into the roof of the mine chamber above said frame to surround the inclosed mass to effect dislodgment thereof from the roof.

20. In miningapparatus, the combination with a supporting frame adapted to rest on the floor of a mine chamber, of a circular ring surrounding said frame, kerfcutting mechanism mounted on said ring to travel therewith circularly, means for ro tating said ring to effect circular feeding movement of said herf-cutting mechanism while the latter is inclined upwardly from said ring toward. the vertical aXis of the iii-ass to be cut, and means for feeding the kerf-cutting mechanism toward such axis to gradually increase the depth of the lrerf being cut.

21. In mining apparatus, the combination with a supporting frame adapted to rest on the floor of a mine chamber, of a supplemental frame mounted thereon for rotary movement relatively thereto, lrerf-cutting mechanism mounted on said supplemental frame to move bodily therewith while occune a position inclined upwardly and towarc the central vertical axis of the mass to be cut from the roof of the mine chamber, and means for operating said kerf-cutting mechanism including rotary movement of said supplemental frame to effect the dislodg'ment of a frustum of material from the of the mine chamber.

In mining apparatus, the combination with a supporting frame adapted to rest on the floor of a mine chamber and having; a free and unobstructed circular opening extending verti tally therethrough, of a supplemental frame mounted for circumferential movement on said supporting frame on an upright axis at the center of said circular opening, kerf-cuttiiig mechanism mounted on said supplemental frame for adjustment to a position inclined upwardly toward such central upright axis and for adjustment to a position inclined downwardly toward such uprlght axis, and means for operating said kerf-cutting mechanism to effect the dislodgment of a frustum of a cone of material from the roof of the mine chamber into such unobstructed opening when said kerf-cut ting mechanism is inclined upwardly and to effect the dislodgment of a frustum of a cone in the floor of the mine chamber belowsaid unobstructed opening when said kerf-cutting mechanism is inclined clownwardly.

23. In mining apparatus, the combination with a supporting frame adapted to rest in a stationary position on a mine floor, of kerf-cutting mechanism mounted thereon in position to cut a kerf in the roof of a mine chamber above said frame, and means for operating said kerf-cutting mechanism to cifcct the dislodgment from such roof of a section of material of a height approximately equal to the height between the floor and roof of the mine chamber and into position between the planes of the floor and roof while said supporting frame remains stationary.

24-. In mining apparatus, the combination with a supporting frame having an unobstructed opening extending vertically therethrough for the passage of a dislodged section of material from the roof of the mine chamber, of a plurality of kerf-cutting devices mounted on said frame for bodily movement relatively thereto, means for feeding each of said cutting devices into the roof longitudinally of the cutting devices, and means for feeding said cutting devices laterally along" said frame about a predetermined mass of material in the roof and around said unobstructed openings,

In mining apparatus, the combination with a frame adapted to rest in a stationary position on the mine floor, of a plurality of kerf-cutters movable bodily relatively to said frame, means for feeding said kerfcutters on an incline toward an upright axis into material above said frame. and means for feeding the cutters laterally to hcrf-cut about a predetermined mass to enable a tapering section to be dislodged from the space above said fr me.

In mining apparatus, the combination with a main frame, of a supplemental frame mounted on said main frame, kerf cutting mechanism mounted on said supplemental frame, and means for operating said kerf cutting mechanism to effect the dislodgment of tapering section of material, said main and supplemental frames having openings in their peripheries adapted to register to enable the dislodged section of material to be separated from sait frames.

27. In mining apparatus. the combination with a main frame adapted to rest in a stationary position on the floor of a mine chamber, of a supplemental frame mounted on said main frame for circumferential movement relatively thereto, kerf-cutting mechanisn'r mounted on said supplemental frame and movable circumferentially therewith,

' means for moving said supplemental frame on said main frame to feedsaid cutting mechanism circumferentially, and means for feeding the cutting mechanism upwardly on an incline toward the upright axis of circumferential movement of said supplemental frame and into the material of the roof of the mine chamber to effect the dislodgment of a conical-shaped section of material from said roof.

28'. In mining apparatus, the combination with a frame, of mechanism mounted thereon for effecting the dislodgment of a mass of material from its native bed in a mine, to a position surrounded by said frame, and means for letting the said dislodged mass down to such position without shock or jar.

29. In mining apparatus, the combination with a frame, of a plurality of devices mounted on said frame in position for engagin'g a mass of material partially cut out from its native bed, and means individual to each of said devices for operating the same to effect dislodgment of said mass of material by alternate operation of said devices. v

80. In mining apparatus, the combination with a supporting frame, of devices mounted on said framework and extending toward the center thereof in position to support a block of material above said devices while said block of material is resting by gravity thereon, and means for actuating said devices to engage the block of material and support the same as set forth while letting the block move gradually by gravity downwardly away from the unmined mass.

31. In mining apparatus, the combination with a supporting frame, of devices thereon in position to engage the cut section of material in its native bed in a mine, and

means for operating'said devices to support such cut section above the same and while such cut section is in its original or native position, and for letting such section move away from its native position downwardly by grz ivity while being supported above said devices.

32. In mining apparatus, the combination with a frame, of supporting mechanism mounted on said frame, and means for swinging said supporting mechanism from a generally horizontal position extending laterally from said frame in position to support a section of mined material, to an upright position free from such section ofmaterial.

In mining apparatus, the combination *v'itli a frame, of spiumia'y of Supporting ar smeunted en aid ame et spaced Ill-Ell.

apart positions, and means for operating said arms'to-lower a mass of material from the roof of a mine to the floor thereof.

34L. In mining apparatus, the combination with open framework, of a plurality of supporting devices extending toward the interior of said frame-work and mounted on the latter in spaced-apart positions, and means for operating said devices to support and lower a dislodged section of material from its native position in a mine.

3-5. In mining apparatus, the combination with a supporting frame having an unobstructed opening therethrough for the passage of dislodged material, of mechanism mounted on said frame for carrying the previously dislodged mass of material from its native position into said opening in a direction substantially at right angles to the exposed face of said dislodged mass, and means for operating said carrying means to effect such movement of said dislodged mass of material.

36 In mining apparatus, the combination with a supporting frame, of a swinging lever pivoted to said frame to extend laterally therefrom or -to extend transversely thereof, a fluid actuated plunger, a pitman connected between said plunger and said lever intermediate the ends of the latter, and means for operating and controlling said plunger to actuate said swinging lever into position for engaging material tending to move transversely of said frame and near the same, and for moving said lever-to its transverse position to permit free movement of such material transversely of said frame and near the same.

87. In mining apparatus, the combination with asupporting frame, of a plurality of devices mounted on said frame in position for engaging the exposed surface of a par-s tially dislodged mass of material in its native position in a mine, and means foroperating said devices independently of each other to engage such exposed surface of said partially dislodged mass and wholly dislodge the same.

38'. In mining apparatus, the combination with a supporting frame, of a plurality of swinging arnis extending toward the interior of said frame but adapted to occupy positions in engagement with a partially dislodged mass of material in a mine, and means for independently coi'itrolling said arms to swing the same to secure complete dislodgment of such mass of material.

39. In mining apparatus, the combination with a circular frame, of swinging devices mounted on said frame in spaced-apart positions and each directed toward the center L herisental pesitiens: fer supporting a block of material and to swing said devices to upright positions to let said block of material down from its native position.

l0. In mining apparatus, the combination with an arc-shaped frame, of a plurality of pairs of arms mounted on said frame to extend toward the center thereof in position to engage a section of mined material and carry the same, and means for operating said arms by swinging the same into substantially horizontal positions for supporting such mined material and by swinging said arms into upright positions to permit the mined mass of material to descend by gravity into said frame.

41. In mining apparatus, the combination with a frame, of a pair of spaced-apart arms, and means for swinging said pair of arms simultaneously against the roof of a mine chamber and simultaneously down to an upright position.

l2. In mining apparatus, the combination with a supporting frame having a free and unobstructed opening therethrough for the passage of a block of material, of a plurality of pairs of arms mounted on said frame for swinging movement at spaced apart positions into and out of said opening, and means for operating said pairs of arms to support said block of material resting thereon and letting same down by gravity from its native position into said opening.

43. In mining apparatus, the combination with a circular frame, of a plurality of pairs of spaced-apart arms mounted in spaced apart positions on said circular frame for swinging movement toward the center thereof, and means for operating each pair of arms independently of another pair to support a block of material in its native position, to dislodge the same and carry it away from its native position.

44. In mining apparatus, the combination with a main frame, of a supplemental frame mounted on said main frame for rotary movement, kerfcutting apparatus mounted on said supplemental frame, means for operating said kerf-cutting apparatus including the feed thereof into the material, means for rotating said supplemental frame to feed said lrerf-cutting apparatus in an are, a plurality of independently operated pairs of arms piv otally mounted on said supplemental frame, means for operating said arms to engage the section of material while being cut to hold it in place in its native position, and con trolling mechanism to cause said arms to dislodge the said out section and lower the same from the roof to the floor of the mine chamber.

4-5. In mining apparatus, the combination with a supporting frame adapted to rest in stationary position on the floor of a mine chamber, of a supplemental.=-frame mounted thereon and confined thereto for a predetermined relative movement, kerf-cutting mechanism mounted on said supplemental frame and movable bodily therewith, means for driving said kerf-cutting mechanism, and means for feeding said cutting mechanism circularly and conically to effect the dislodgment of a tapering mass of material from the roof of the mine chamber while said supporting frame remains in stationary position.

@6. In mining apparatus, the combination with a supporting frame adapted to rest in parallel position in a mine chamber, of a supplemental frame mounted on said supporting frame and confined thereto for movement in a circle relatively thereto, cutting mechanism mounted on said supplemental frame and movable bodily there with, means for moving said supplemental frame in a circle relatively to said main frame to efiect circular feeding movement of said cutting mechanism, and means for feeding said cutting mechanism toward the apex of the cone to efiect the cutting of a kerf in the roof above said frame in the shape of a frustum of a cone.

47. In mining apparatus, the combination with a supporting frame adapted to rest in stationary position on the floor of a mine chamber, of cutting mechanism mounted on said frame for movement relatively thereto, and means for operating said cutting mechanism to cut into the roof above said sup porting frame along lines converging toward each other and surrounding a conical mass of material in said roof.

48. In mining apparatus, the combination with a supporting frame, of cutting mech anism mounted thereon, means for operat ing said cutting mechanism to cut a conical kerf surrounding a tapering mass of material, and additional cutting mechanism for effecting a deeper cut near the apeX of such tapering mass of material in the roof of the mine chamber to effect the dislodgment of such tapering mass of material from such roof.

4:9. In mining apparatus, the combination with an arc-shaped supporting frame adapted to rest in stationary position on the floor of a mine chamber, of an additional arcshaped frame mounted on said supporting frame for feeding movement in a circle, cutting mechanism mounted on said additional frame, means for feeding said additional frame in a circle together with the cutting mechanism mounted thereon while said supporting frame remains in stationary posi tion, and means for feeding the cutting mechanism toward the apex of a cone having an upright aXis to effect the cutting of a conical kerf surrounding and taperingmass' of material in its native bed in a mine.

50. In mining apparatus, the combination with an arc-shaped supporting frame adapted to rest on the floor of a mine chamber, of an additional arc-shaped frame mounted for movement in a circle, cutting mechanism mounted on said additional frame for arcuate movement therewith, means for feeding said additional frame together with the cutting mechanism mounted thereon While said supporting frame remains stationary, means for feeding the cutting mechanism toward the apex of a cone having an upright axis to cooperate with said arcuate feeding movement to produce a conical kerf in the native material in a mine, and additional cutting mechanism carried by said additional frame for cutting the material near the apex of the cone to cause the tapering mass of material to be dislodged by its own weight.

In testimony whereof I have signed my name to this specification, on this 3d day of July, A. D. 1917.

EDMUND C. MORGAN.

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