US1501936A - Method of mining - Google Patents

Method of mining Download PDF

Info

Publication number
US1501936A
US1501936A US560394A US56039423A US1501936A US 1501936 A US1501936 A US 1501936A US 560394 A US560394 A US 560394A US 56039423 A US56039423 A US 56039423A US 1501936 A US1501936 A US 1501936A
Authority
US
United States
Prior art keywords
levels
slope
mining
driving
ore
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US560394A
Inventor
Ball Edwin
Clarence E Abbott
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US560394A priority Critical patent/US1501936A/en
Application granted granted Critical
Publication of US1501936A publication Critical patent/US1501936A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21CMINING OR QUARRYING
    • E21C41/00Methods of underground or surface mining; Layouts therefor
    • E21C41/16Methods of underground mining; Layouts therefor

Definitions

  • Our invention relates to mining methods and more particularly to the method of mining iron ore or other material 1 ing in seams 'or in a more or less uniform eposit on an incline plane.
  • One object of the invention is to provide a novel method or a combination of mining operations whereby the development and exp oration work may be pursued and at the same time the mine may be worked to its maximum capacity and the cost of mining lessened.
  • Another object of the invention is to provide a novel method of mining whereby the mine is efliciently ventilated, the safety of the employees obtained and damage to the mine is overcome and prevented.
  • Another object of the invention is to pro vide an improved method of mining in which the blasting, loading and handling operations are facilitated and wherein the ore or material is removed with increased rapidity, thereby lessening the operating costs and increasing the capacity of the mine.
  • FIG. 1 is a p an view showing the referred manner of forming the mine an removing the ore or material in accordance with our invention
  • Fig. 2 is an enlarged view of a part of the mine shown in Fig. 1, illustrating more specifically the method of removing the ore and the haulage operations;
  • Fig. 3 is a pers ective view of a stope illustrating the dril ing and blasting operation;.
  • Fig. 4 is a longitudinal section on line 4-4 of Fig. 1;
  • Fig. 5 is a cross-section on line 5-5 of Fi 1' ig.6 is a plan view of a stope similar to Fig. 3 illustrating the operation of removing broken ore from a stope by means of one type of mechanical ore loader;-
  • Fig. 7 is a section on line 7'7 of Fig. 6.
  • FIG. 3 designates a longitudinal slope or main haulway tunnel which is driven from the surface beneath the ore seam or deposit for a suflicient distance in the initial sta e of the mining operation.
  • a plurality o? lateral levels 4, 6, 8, 10 and 5, 7, 9 and 11 are turned 011' on opposits sides in the ore or other material to be mined.
  • the lateral levels intersect the main slope 3 (shown in Figs.
  • New lateral levels 20 and 21 are then turned off the manways 12 and 13 at the level 16 and the manway ushed forward as at 22 and 23, new leve s 24 being driven across between the manways and the slope 19 raised and connected, new lateral levels 20 and 21 are continually turned 03 thedmanways as the development work procee s.
  • the size or area of the stopes are determined by the condition of the roof, the amount of material necessary to be left to form the pillars such as 52, 52', 52", 54, 55,55, 55", 56, 56', 56, 57, 57*, 57, 5s, 59 to insure safety in working the mine, and by the location of the pillars in the adjacent stapes above and below.
  • the stopin is preferably done in such manner that t e large pillars are left at red or one pillar such as 53 in line wit similar pillars 55 or 61 two stopes above or below.
  • Small pillars 52 and 52 are left in the center or at other locations in the stops where conditions make them necessary or. advisable. This arrangement gives the greatest dpossible protection for economically an safely mining the ore orother material.
  • drilling is beat the top of 5: steps 65 and the holes rilled at an angle as indicated by dotted lines at and 71 to a depth that will break down the maximum amount of material with a minimum charge of explosive.
  • a step or bench such as 66 is left.
  • the next round is drilled at-a regular interval below at substantially the same angle and depth then blasted. This is continued down the stops leaving a regular series of steps or benches 66, 67, 68 and 69 which are drilled and blasted in turn until the limit of the stops is reached, then the etc is uarred up along a line substantia y para lel to the main slope 3.
  • the ribs or sides of the stops are worked in a line substantially arallel to the main haulway slope and at r1 ht angles to the tracks in the lateral levels, t us facilitating the operation line or other mechanical ore loaders, ena ling them to easily reach any part of the stops.
  • the winding 8. paratus of this type of loader is placed on t e tracks 70, 71, 72 and 73 in the levels and sheave blocks 7 4 are attached to timbers 75 or to the rib or footwall, to guide the drag cables 76 and 77.
  • One end of the cable 76 is wound on and secured to a winding drum 78 carried by a car 79, the other end of said cable being attached to the front end of a drag scraper 80 and serving as an inhaul cable.
  • the other cable 77 is wound on a second drum 81 and passes through one or more guide sheave blocks 74 and is attached to the rear of the drag scraper 80, serving as an outhaul cable.
  • the inhaul cable 76 on one drum 8 is wound in, pulling the scraper forward in a straight line, through a chute 82 and dumping into a car 83 on the tracks in the level, the drum 81 running loose during this operation.
  • the inhaul drum is disconnected'from its drive by throwing a suitable clutch and the drum 81 is connected and the outhaul cable wound in returning the pillars 55* thus efliciently and economically removing the broken ore to cars in the levels.
  • the tracks 70, 71, 72, 73 and so forth in each level are laid from the tipples 94, 94', '95, 95, 96, 96, 97 and 97 at the main slo toward the face.
  • These tracks are of t e usual mine construction and are laid so that the grade increases toward the face as it is driven back from the main slope 3 to facilitate tramming, as in many cases the loaded cars may be trammed down by gravity. In such cases either animal or mechanical haulage will be necessary to return the empty cars to the working places.
  • the levels may be double tracked as shown in the level 72 and also a third track may be placed as shown in this level thus allowing a number of cars to await their turn to be dumped into the main haulage skip, or cars may be transferred from one level to another. By this arrangement two cars may be dumped at the same time and the empty cars switched aside until all loaded cars have been dumped, without waiting to return the empty cars to the working places.
  • the levels maybe double tracked at the working places as shown in Fig. 2 in order to facilitate the operation of a mechanical ore leader or if necessary, three tracks may be installed and also a stora track for empty cars may be placed in t e level near the working place to eliminate the delay in waiting on empty cars.
  • a stora track for empty cars may be placed in t e level near the working place to eliminate the delay in waiting on empty cars.
  • the method of mining which consists in driving a main slope beneath an inclined seam or deposit, turning levels laterally from the slope in the deposit, driving manways in advance of the main slope and substantially parallel to the center line thereof, connecting the manways by levels in advance of the slope and raisin the slope from said levels.
  • the method of mining which consists in driving a main slo e, turning lateral levels from the slope. riving manways in advance of and on opposite sides of the slope center line projected, connecting the manways by lateral levels below the forward end of the main slope and excavating the slope from said levels.
  • the method of mining which consists in driving a main slope beneath an inclined seam or deposit, turning levels laterally from the slope in the deposit, driving manways in advance of the main slope and substantially parallel to the center line thereof. connectin the manways by levels. continuing the s o from said levels and driving said levels aterally from the manways.
  • the method of mining which consists in driving a plurality of levels at different elevations from a main slope. raisin inclined upsets from the lower to the higher levels, stoping from the upsets to leave large staggered pillars with smaller pillars between them.
  • the method of mining which consists in driving a main slope, turning lateral levels from the slope, driving manways in advance of and on opposite sides of the slope center line projected, connecting the manways by lateral levels raising the slope from the last named levels, raising upsets from other levels and stoping from said upsets so that the mining operations can proceed without interfering with the development or exploration work.
  • the method of mining which consists in driving a plurality of levels through the deposit, raising upsets at approximately equal intervals from one level to the adjacent higher level, the upsets in the several levels throughout the mine being formed approximately in line and the stoping beincarried on so as to leave lar pillars stan ing in staggered relationship with one another in adjacent levels.
  • the method of mining which consists in driving a main slope below the deposit, driving a plurality of lateral levels through the deposit, raising upsets from the lower to the higher levels, and stoping by drilling and blasting successive benches upsets substantially arallel to said main slope and mechanically conveying the ore thus mined to tram cars in said levels.
  • the method of mining which consists in driving a main slope below the deposit, driving a plurality of lateral levels through the deposit, raising inclined upsets from the lower to the higher levels, drilling and blasting a series of successive benches, substantially parallel to said main slope in said upsets to form inclined stopes from which; the ore can be readily removed, scraping the ore along the inclined stopes to tram cars in said levels and dumping the ore from said tram cars into a skip which traverses the main slope.
  • the method of mining which consists in driving a main slope, turning levels lat erally from the slope, drivin a manway in advance of the main slope su stantmlly parallel to the projected center line thereof, driving lateral levels from said manway in advance of and. below the main slope and raising the slope from the lower levels.
  • the method of mining which consists in driving a main slope beneath an inclined seam or deposit, turning levels from said main slope in the deposit, driving a manway in advance of the main slope in the general direction thereof turning a lateral level from said manway in advance of the main slope and connecting the slope from said advance lateral level.

Description

July 22 1924.
E. BALL ET AL METHOD OF MINING 1922 5 Sheets-Sheet 1 Filed May 1" 7' INVENTORS lZW/MEALL, ARE/YCEZTAMO r7:
ATTORNEY.
July 22, I924.
E. BALL ET AL METHOD OF MINING INVENTORS I D W/// BALL. By CLARENCEZADD'OTZ 5 SheetsSheet 2 Filed May 12,
A T] 'ORNE Y.
Jul 22, 1924.
E. BALL ET AL METHOD OF MINING Filed May 12 5 Sheets-Sheet 5 Him [DWI/Yfi/ILL CLARE/YCEZAZIDOTT.
A TTORNEY.
July 22. 1924.
E. BALL ET AL METHOD OF MINING Filed May 12. 1922 5 Sheets-Sheet 4 INVENTORS .lQW/IV 5A LL CLARE/vcEZZ'AEBOrJI A TTORN E Y.
July 22 1924. 1,501,936
E. BALL ET AL METHOD OF MINING Filed May 12, 1922 5'Sheets-Sheet 5 INVENTORS ZQW/Nfi/ILL. CLARENC'EZAZBOTT.
A TTORNE Y.
Patented July 22, 1924.
UNITED STATES BALL, OF BIRMINGHAM, CLARENCE E. ABBOTT, 01. B It;
PATENT OFFICE.
' ALLBAIA.
ma'rnon or ,umnm.
Application filed Kay 12, 1922. Serial In. 560,884.
To all whom it may concern:
Be it known that we, EDWIN BALL and CLARENCE E. ABBo'rr, citizens of the United States, and residents of Birmingham, Alabama, and Bessemer, Alabama, respectively, have invented certain new and useful Improvements in Method of Mining, of which the following is a specification.
Our invention relates to mining methods and more particularly to the method of mining iron ore or other material 1 ing in seams 'or in a more or less uniform eposit on an incline plane.
One object of the invention is to provide a novel method or a combination of mining operations whereby the development and exp oration work may be pursued and at the same time the mine may be worked to its maximum capacity and the cost of mining lessened.
Another object of the invention is to provide a novel method of mining whereby the mine is efliciently ventilated, the safety of the employees obtained and damage to the mine is overcome and prevented.
Another object of the invention is to pro vide an improved method of mining in which the blasting, loading and handling operations are facilitated and wherein the ore or material is removed with increased rapidity, thereby lessening the operating costs and increasing the capacity of the mine.
Other objects of the invention will be apparent from the following specification when read in connection with the accompanying drawi in which- Fig. 1 is a p an view showing the referred manner of forming the mine an removing the ore or material in accordance with our invention;
Fig. 2 is an enlarged view of a part of the mine shown in Fig. 1, illustrating more specifically the method of removing the ore and the haulage operations;
Fig. 3 is a pers ective view of a stope illustrating the dril ing and blasting operation;.
Fig. 4 is a longitudinal section on line 4-4 of Fig. 1;
Fig. 5 is a cross-section on line 5-5 of Fi 1' ig.6 is a plan view of a stope similar to Fig. 3 illustrating the operation of removing broken ore from a stope by means of one type of mechanical ore loader;-
Fig. 7 is a section on line 7'7 of Fig. 6.
Referring to the drawings 3 designates a longitudinal slope or main haulway tunnel which is driven from the surface beneath the ore seam or deposit for a suflicient distance in the initial sta e of the mining operation. A plurality o? lateral levels 4, 6, 8, 10 and 5, 7, 9 and 11 are turned 011' on opposits sides in the ore or other material to be mined. The lateral levels intersect the main slope 3 (shown in Figs. 4 and 5) at locations elevated from the floor of said slope so as to facilitate the dumpin of ore from the tram cars in said levels into the skip which traverses the main haulway slo After the slope or main haulway tunne 3 has been projected a sufficient distance, manways 12 and 13 are driven in the do it parallelling the slope on op osite sides t ereof and leavin suflicient ies of ore or -material standing between the slope and manways to insure safety. These manways are then driven to the surface, the lateral levels are continued and the manways driven in advance or ahead of the slo .on both sides of the projected center line t ereof. At intervals advance levels 16 and 17 are driven across the S10 0 center line from one manway to the ct er and the slope vated or raisedfrom the lower to the next higher level. New lateral levels 20 and 21 are then turned off the manways 12 and 13 at the level 16 and the manway ushed forward as at 22 and 23, new leve s 24 being driven across between the manways and the slope 19 raised and connected, new lateral levels 20 and 21 are continually turned 03 thedmanways as the development work procee s.
The advantages of this system of development are, that the manways being driven in the ore or material, any change in grade occasioned by faults, dips or 0t or causes may be rectified with a minimum of expense, and by raising the slope from the advance levels the construction of bulkheads or pentices, for the protection of the workmen against accidents on themain heulway, is made unnecessary. Also the disadvantage of water flowing down into the face while driving the slope is eliminated.
fter a'number of lateral levels such as 4, 5, 10, 11, 29, 30 and so forth have been driven a suficient distance from the manways 12, 13 to leave gotecting pillars 14, 16, upsets or raises 40, 48, 46, 47 are driven 18-19 exca of the various types of dra through at intervals'to the level above and stoping is begun as at 44, 46, $9 and 51. The size or area of the stopes are determined by the condition of the roof, the amount of material necessary to be left to form the pillars such as 52, 52', 52", 54, 55,55, 55", 56, 56', 56, 57, 57*, 57, 5s, 59 to insure safety in working the mine, and by the location of the pillars in the adjacent stapes above and below. The stopin is preferably done in such manner that t e large pillars are left at red or one pillar such as 53 in line wit similar pillars 55 or 61 two stopes above or below. Small pillars 52 and 52 are left in the center or at other locations in the stops where conditions make them necessary or. advisable. This arrangement gives the greatest dpossible protection for economically an safely mining the ore orother material.
After the upsets 40, 42, 43 and 45 and so forth have broken into the level above, underhand stoping at 44, 46, 49 and 51 is commenced on one side of each stops as the pillars 56, 60, 63 and 65 form one side of each of the upsets. O
Referring to Fi 3 and 6, drilling is beat the top of 5: steps 65 and the holes rilled at an angle as indicated by dotted lines at and 71 to a depth that will break down the maximum amount of material with a minimum charge of explosive.
After one round of blasting, a step or bench such as 66 is left. The next round is drilled at-a regular interval below at substantially the same angle and depth then blasted. This is continued down the stops leaving a regular series of steps or benches 66, 67, 68 and 69 which are drilled and blasted in turn until the limit of the stops is reached, then the etc is uarred up along a line substantia y para lel to the main slope 3. By the use of this method the ribs or sides of the stops are worked in a line substantially arallel to the main haulway slope and at r1 ht angles to the tracks in the lateral levels, t us facilitating the operation line or other mechanical ore loaders, ena ling them to easily reach any part of the stops.
Figs. 2, 6 and illustrate a type of drag line mechanical ore loader adapted to be used in connection with our improved method of mining. The winding 8. paratus of this type of loader is placed on t e tracks 70, 71, 72 and 73 in the levels and sheave blocks 7 4 are attached to timbers 75 or to the rib or footwall, to guide the drag cables 76 and 77. One end of the cable 76 is wound on and secured to a winding drum 78 carried by a car 79, the other end of said cable being attached to the front end of a drag scraper 80 and serving as an inhaul cable. The other cable 77 is wound on a second drum 81 and passes through one or more guide sheave blocks 74 and is attached to the rear of the drag scraper 80, serving as an outhaul cable.
In 0 ration, the inhaul cable 76 on one drum 8 is wound in, pulling the scraper forward in a straight line, through a chute 82 and dumping into a car 83 on the tracks in the level, the drum 81 running loose during this operation. After the scraper has discharged its load, the inhaul drum is disconnected'from its drive by throwing a suitable clutch and the drum 81 is connected and the outhaul cable wound in returning the pillars 55* thus efliciently and economically removing the broken ore to cars in the levels.
The tracks 70, 71, 72, 73 and so forth in each level are laid from the tipples 94, 94', '95, 95, 96, 96, 97 and 97 at the main slo toward the face. These tracks are of t e usual mine construction and are laid so that the grade increases toward the face as it is driven back from the main slope 3 to facilitate tramming, as in many cases the loaded cars may be trammed down by gravity. In such cases either animal or mechanical haulage will be necessary to return the empty cars to the working places. The levels may be double tracked as shown in the level 72 and also a third track may be placed as shown in this level thus allowing a number of cars to await their turn to be dumped into the main haulage skip, or cars may be transferred from one level to another. By this arrangement two cars may be dumped at the same time and the empty cars switched aside until all loaded cars have been dumped, without waiting to return the empty cars to the working places. I
The levels maybe double tracked at the working places as shown in Fig. 2 in order to facilitate the operation of a mechanical ore leader or if necessary, three tracks may be installed and also a stora track for empty cars may be placed in t e level near the working place to eliminate the delay in waiting on empty cars. However, in our improved method we do not limit ourselves to any particular haulage system or type of underground tipple.
An advantage in the use of our method of mining, which will be ap arent to those skilled in the art, is the 'e imi'nation of a commonly used system of driving levels at intervals from the main haulways and at intervals driving upsets connecting the levels andsleaving narrow, horizontal pillars between the levels. Such a stem necessitates much costly narrow wor in continually driving the face, a high explosive cost in driving the same and permits of a very limited working face, necessitating a much greater number of working levels than required by our system, as well as greatly limiting the economical use of the various types of mechanical ore loaders in handling the broken material. In mining according to our improved method the narrow work, with its high cost of blasting and handling is confined to driving past pillars, as the maximum amount of material may be broken with a minimum amount of explosives and a much larger working face may be obtained in the stopes. enabling a considerable output from comparatively few working levels, thereby reducing the cost of haulage and greatly facilitating the economical use of mechanical ore loaders.
What we claim is:
1. The method of mining which consists in driving a main slope beneath an inclined seam or deposit, turning levels laterally from the slope in the deposit, driving manways in advance of the main slope and substantially parallel to the center line thereof, connecting the manways by levels in advance of the slope and raisin the slope from said levels.
2. The method of mining which consists in driving a main slo e, turning lateral levels from the slope. riving manways in advance of and on opposite sides of the slope center line projected, connecting the manways by lateral levels below the forward end of the main slope and excavating the slope from said levels.
3. The method of mining which consists in driving a main slope beneath an inclined seam or deposit, turning levels laterally from the slope in the deposit, driving manways in advance of the main slope and substantially parallel to the center line thereof. connectin the manways by levels. continuing the s o from said levels and driving said levels aterally from the manways.
4. The method of mining which consists in driving a plurality of levels at different elevations from a main slope. raisin inclined upsets from the lower to the higher levels, stoping from the upsets to leave large staggered pillars with smaller pillars between them.
5. The method of mining which consists in driving a main slope, turning lateral levels from the slope, driving manways in advance of and on opposite sides of the slope center line projected, connecting the manways by lateral levels raising the slope from the last named levels, raising upsets from other levels and stoping from said upsets so that the mining operations can proceed without interfering with the development or exploration work.
6. The method of mining which consists in driving a plurality of levels through the deposit, raising upsets at approximately equal intervals from one level to the adjacent higher level, the upsets in the several levels throughout the mine being formed approximately in line and the stoping beincarried on so as to leave lar pillars stan ing in staggered relationship with one another in adjacent levels.
7. The method of mining which consists in driving a main slope below the deposit, driving a plurality of lateral levels through the deposit, raising upsets from the lower to the higher levels, and stoping by drilling and blasting successive benches upsets substantially arallel to said main slope and mechanically conveying the ore thus mined to tram cars in said levels.
8. The method of mining which consists in driving a main slope below the deposit, driving a plurality of lateral levels through the deposit, raising inclined upsets from the lower to the higher levels, drilling and blasting a series of successive benches, substantially parallel to said main slope in said upsets to form inclined stopes from which; the ore can be readily removed, scraping the ore along the inclined stopes to tram cars in said levels and dumping the ore from said tram cars into a skip which traverses the main slope.
9. The method of mining which consists in driving a main slope, turning levels lat erally from the slope, drivin a manway in advance of the main slope su stantmlly parallel to the projected center line thereof, driving lateral levels from said manway in advance of and. below the main slope and raising the slope from the lower levels.
10. The method of mining which consists in driving a main slope beneath an inclined seam or deposit, turning levels from said main slope in the deposit, driving a manway in advance of the main slope in the general direction thereof turning a lateral level from said manway in advance of the main slope and connecting the slope from said advance lateral level.
In witness whereof, we have hereunto signed our names.
EDWIN BALL. CLARENCE E. ABBOTT.
rom said
US560394A 1923-05-12 1923-05-12 Method of mining Expired - Lifetime US1501936A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US560394A US1501936A (en) 1923-05-12 1923-05-12 Method of mining

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US560394A US1501936A (en) 1923-05-12 1923-05-12 Method of mining

Publications (1)

Publication Number Publication Date
US1501936A true US1501936A (en) 1924-07-22

Family

ID=24237620

Family Applications (1)

Application Number Title Priority Date Filing Date
US560394A Expired - Lifetime US1501936A (en) 1923-05-12 1923-05-12 Method of mining

Country Status (1)

Country Link
US (1) US1501936A (en)

Similar Documents

Publication Publication Date Title
CN104564050B (en) Equipment for heading and anchoring parallel operation construction
US5782539A (en) Wall-to-wall surface mining process
WO2016095538A1 (en) Double-roadway combined speedy tunnelling and waste rock removal system and method
CA2883015C (en) A system for the reduction in applied energy, improved efficiencies and reduced costs in open pit mining
US8905486B2 (en) Underground mining
CN104405437A (en) Mining method employing solid filling and fully-mechanized coal mining hybrid working face
CN111980709B (en) Continuous mining method for high-inclination-angle thick coal seam slope coal
AU2014202712B2 (en) Ore removal production line, twin ramps and ground support installation method
CN108756875A (en) The continuous quarrying apparatus of row's open coal mine medium-thickness seam and method in a kind of
CN111561317A (en) Scraping coal mining method for steeply inclined coal seam
AU2015100065C4 (en) A System for the Reduction in Applied Energy, Improved Efficiencies and Reduced Costs in Open Pit Mining
RU2559262C1 (en) Method of open development of deposits with use of combined transport
US1501936A (en) Method of mining
CN204476407U (en) A kind of pick anchor parallel operations construction equipment
AU2014100343B4 (en) A System for the Reduction in Applied Energy, Improved Efficiencies and Reduced Costs in Open Pit Mining
RU2039280C1 (en) Excavating and loading complex for opencast mining
US1622837A (en) System for mining
SU1011861A1 (en) Method of working rich deposits of minerals
RU2186982C1 (en) Method of preparation of new haulage level and excavator-railway complex for method embodiment
CN217681844U (en) Movable slag discharging device for underground coal mine excavation roadway
CN108952713B (en) Recovery method of scattered minerals in closed-section stope
US1999931A (en) Coextensive room system with mechanical conveyers
SU1479645A1 (en) Method of strip mining of mineral depostits
SU771341A1 (en) Mining machine feed mechanism
US1632800A (en) System for mining