Construction method for continuous mining machine having device continuously providing provisional roof support

Abstract

A method for operating a continuous mining machine having a device continuously providing provisional roof support, wherein the mining machine a rolling roof-protection portion which is fixed on a main machine frame of the continuous mining machine via a front column structure and a rear column structure. While the machine is cutting, the roof-protection device performs continuous load holding on a roof, and after cutting, performs support operations, thereby achieving simultaneous performance of cutting and support operations, and improving tunneling efficiency. Different support strengths are configured according to the hardness, completeness, and quality indicators of rock on a mine roof, such that the device is able to effectively support the roof.

1 - 9 . (canceled) 
     
     
         10 . A method for operating a continuous mining machine with a continuous temporary roof protection device wherein the continuous mining machine comprises a main machine part, a loading device, a horizontal-shaft cutting drum, a conveying device and a crawler travel device, wherein the horizontal-shaft cutting drum is hinged to the front portion of the main machine part, the front portion of the conveying device is connected to the loading device and the conveying device is fixedly connected to the main machine part, and the crawler travel device employs hydraulic driving and is fixed to the bottom of the main machine part, wherein the continuous mining machine further comprises a continuous temporary roof protection device, the loading device and the horizontal-shaft cutting drum are disposed in front of the continuous temporary roof protection device, and the continuous temporary roof protection device comprises a rolling roof protection part fixed to the main machine part of the continuous mining machine via a front pillar structure and a rear pillar structure;
 the rolling roof protection part comprises a frame body, a closed crawler track loop, a first roller, a second roller and an elastic load bearing structures, wherein the first roller and the second roller are respectively hinged to two ends of the frame body, the closed crawler track loop is wound on the first roller and the second roller and is in a rolling connection with the first roller and the second roller, a plurality of guide sleeves are fixed inside the frame body, the guide sleeves are connected with the elastic load bearing structures, and the elastic load bearing structures are in a rolling connection with the closed crawler track loop;   the front pillar structure comprises a front square inner sleeve, a front square outer sleeve and a front height-adjusting oil cylinder, wherein the bottom of the front square outer sleeve is fixed to the main machine part of the continuous mining machine by bolts, the front square inner sleeve is embedded in the front square outer sleeve, the bottom of the cylinder body of the front height-adjusting oil cylinder is hinged to the front square outer sleeve, a piston rod of the front height-adjusting oil cylinder is hinged to the front square inner sleeve, and the top end of the front square inner sleeve is hinged to the frame body;   the rear pillar structure comprises a rear square inner sleeve, a rear square outer sleeve and a rear height-adjusting oil cylinder, wherein the bottom of the rear square outer sleeve is fixed to the main machine part of the continuous mining machine by bolts, the rear square inner sleeve is embedded in the rear square outer sleeve, the bottom of the cylinder body of the rear height-adjusting oil cylinder is hinged to the rear square outer sleeve, a piston rod of the rear height-adjusting oil cylinder is hinged to the rear square inner sleeve, and a waist-shaped hole structure at the top end of the rear square inner sleeve is slidably and rotatably connected with the frame body via a pin shaft;   an oil inlet bypass of a rodless cavity of the front height-adjusting oil cylinder and an oil inlet bypass of a rodless cavity of the rear height-adjusting oil cylinder are connected with an accumulator respectively, two oil inlets of the front height-adjusting oil cylinder are connected with a reversing valve via a hydraulic lock, two oil inlets of the rear height-adjusting oil cylinder are connected with the reversing valve via another hydraulic lock, and a pressure gauge and an overflow valve are provided between the reversing valve and the hydraulic locks;   the horizontal-shaft cutting drum is adjustable in length and its maximum length is the same as the width WO of the roadway to be constructed, and the total width of the loading device is smaller than the width WO of the roadway to be constructed;   the construction method comprises the following steps:   
       a. classifying the roof strata of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses” according to the geological conditions of the region where the roadway is to be constructed, wherein the continuous mining machine is suitable for constructing roadways with Class I, Class II or Class III roof strata; 
       b. qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”, and determining the supporting strength Pr of the continuous temporary roof protection device according to the result of qualitative classification and a quality index of the rock mass; 
       c. calculating the pressure Pc on the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder with the following formula, according to the supporting strength Pr determined in the step b: 
       
         
           
             
               
                 
                   
                     
                       
                         P 
                         c 
                       
                       = 
                       
                         
                           
                             P 
                             r 
                           
                           × 
                           WO 
                           × 
                           L 
                         
                         
                           4 
                           × 
                           3.14 
                           × 
                           
                             R 
                             2 
                           
                         
                       
                     
                     ; 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         wherein R is the cylinder diameter of the front height-adjusting oil cylinder or the rear height-adjusting oil cylinder, L is the length of contact surface between the rolling roof protection part and the roof, and WO is the width of the roadway to be constructed; 
       
       d. setting the pressure on the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder according to the pressure result calculated in the step c, i.e., adjusting the overflow pressure value of the overflow valve to the pressure value calculated in the step c with the aid of the pressure gauge; 
       e. manipulating the handle of the reversing valve to supply oil to the accumulator, the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder while observing the pressure indicated by the pressure gauge, and holding the pressure for 3 s when the pressure indicated by the pressure gauge fails to increase anymore; 
       f. determining the cutting footage of the continuous mining machine according to the array pitch of the roof bolts in a predefined scheme to set the distance of the cutting footage in each cycle to be equal to the array pitch of the roof bolts in the predefined scheme, operating the horizontal-shaft cutting drum of the continuous mining machine to cut the coal according to the distance of the cutting footage in each cycle, shoveling the coal and rock cut by the horizontal-shaft cutting drum with the loading device, and conveying the coal and rock with the conveying device to the rear part and then conveying the coal and rock away; 
       g. advancing the continuous mining machine forward by a distance corresponding to the cutting footage by means of the crawler travel device after the coal cutting, while the rolling roof protection part of the continuous temporary roof protection device persistently supports the roof of the constructed roadway; 
       h. operating the continuous mining machine to carry out the next cycle of coal cutting after the advancing, while workers use a roof bolter to support the roof with rock bolts behind the continuous mining machine; 
       i. executing the step b again after cutting to a preset distance, determining the supporting strength Pr of the continuous temporary roof protection device again according to the conditions of the roof rock mass of the roadway to be constructed, and operating the continuous mining machine to do the construction work forward in a preset roadway direction, till the roadway driving work is completed. 
     
     
         11 . The method according to  claim 10 , wherein the total width of the loading device is smaller than the width WO of the roadway to be constructed by 200 mm. 
     
     
         12 . The method according to  claim 11 , wherein the step b comprises:
 (1) qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”;   (2) determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.02 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff rock and the rock mass is integral, and the quality index BQ of the rock mass is BQ>550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.05 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally integral, or the rock is generally stiff and the rock mass is integral, and the quality index BQ of the rock mass is 451 to 550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.1 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally fractured, or the rock is generally stiff and the rock mass is generally integral, or the rock is generally soft and the rock mass is integral, and the quality index BQ of the rock mass is 351 to 450.   
     
     
         13 . The method according to  claim 10 , wherein in the step i, the preset distance is 50 m. 
     
     
         14 . The method according to  claim 10 , wherein the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway. 
     
     
         15 . The method according to  claim 10 , wherein the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track. 
     
     
         16 . The method according to  claim 15 , wherein the hard rubber is bonded to the track shoe substrate by epoxy resin and fixed to the track shoe substrate by hex screws. 
     
     
         17 . The method according to  claim 10 , wherein the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller to tension up the closed crawler track loop. 
     
     
         18 . The method according to  claim 10 , wherein two continuous temporary roof protection devices are provided. 
     
     
         19 . The method according to  claim 11 , wherein in the step i, the preset distance is 50 m. 
     
     
         20 . The method according to  claim 11 , wherein the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway. 
     
     
         21 . The method according to  claim 11 , wherein the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track. 
     
     
         22 . The method according to  claim 21 , wherein the hard rubber is bonded to the track shoe substrate by epoxy resin and fixed to the track shoe substrate by hex screws. 
     
     
         23 . The method according to  claim 11 , wherein the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller to tension up the closed crawler track loop. 
     
     
         24 . The method according to  claim 11 , wherein two continuous temporary roof protection devices are provided. 
     
     
         25 . The method according to  claim 12 , wherein in the step i, the preset distance is 50 m. 
     
     
         26 . The method according to  claim 12 , wherein the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway. 
     
     
         27 . The method according to  claim 12 , wherein the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track. 
     
     
         28 . The method according to  claim 25 , wherein the hard rubber is bonded to the track shoe substrate by epoxy resin and fixed to the track shoe substrate by hex screws. 
     
     
         29 . The method according to  claim 12 , wherein the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller to tension up the closed crawler track loop.