CN103790546B - Gas pre-drainage boring ickings backfill method for sealing - Google Patents
Gas pre-drainage boring ickings backfill method for sealing Download PDFInfo
- Publication number
- CN103790546B CN103790546B CN201410051006.1A CN201410051006A CN103790546B CN 103790546 B CN103790546 B CN 103790546B CN 201410051006 A CN201410051006 A CN 201410051006A CN 103790546 B CN103790546 B CN 103790546B
- Authority
- CN
- China
- Prior art keywords
- duff
- sealing
- drainage
- compound
- pouch
- 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 - Fee Related
Links
Landscapes
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
Abstract
The invention discloses a kind of gas pre-drainage boring ickings backfill method for sealing, first with drilling tool to coal bed drilling while, coal dust is collected and filters or pulverize filtration, keeps coal particle size to be not more than 1mm；Fine breeze after filtering inputs in agitator and adds cement and duff compound is made in white glue with vinyl stirring, and the weight percent composition of this each composition of duff compound is: fine breeze 60～70%, cement 25～35%, white glue with vinyl 4～6%；Adding water and continue stirring, making water and duff compound ratio is 0.3～0.5.The present invention utilizes duff slurry to replace cement mortar, carries out sealing of hole, and coal slurry is tightly combined with coal body, and coal body is not polluted by ungauged regions.Fine breeze, as sealing material, can be gathered materials on the spot, and reduces cost of winning, allocates simple and convenient, determine that sealing of hole effect is the best through test of many times.And the foreign material such as too many cement sandstone will not be remained after working seam, exploitation purity is high, and production efficiency is high, is especially suitable for promotion and implementation.
Description
Technical field
The present invention relates to the hole sealing technology in technical field of coal mine, be specifically related to a kind of gas pre-drainage boring ickings backfill method for sealing.
Background technology
Along with coal industry and the high speed development of coal production mechanization, dust hazard problem in coal production is the severeest, and coal worker's pneumoconiosis disease sickness rate is higher, and coal-dust explosion happens occasionally, Gas Outburst is a kind of serious natural disaster of underground coal mine, the serious safety in production restricting colliery.The coal mining process of standard needs first to Gas Drainage from Virgin Coal Seams, and due to buried underground, coal seam, between coal seam, pressure is big, needs to insert gas drainage pipe after punching in coal seam, is extracted out by depths, coal seam methane gas.The process that draws out methane needs to seal releasing pipe, and tradition short-cut method is directly to use cement mortar sealing of hole, is inserted by gas drainage pipe bottom the sealing of hole section of boring and blocks then by cementing with timber wedge or cotton yarn.Just can bleed after Behavior of Hardened Cement Paste slurry solidification.Expending the time with cement mortar sealing of hole water filling long, sealing effectiveness is not good enough, bears air pressure indifferent, and expends that material is many, inconvenient operation.
Utilizing cement mortar tight with coal body joint portion it addition, existing, have minimal shrink after cement slurry sets, sealing effectiveness is poor, also can pollute coal body, causes the ash of coal to increase.
Summary of the invention
It is an object of the invention to the problem and shortage existed for prior art, it is provided that a kind of multistage pouch hole packer that can effectively prevent spray orifice.
For achieving the above object, adopt the following technical scheme that a kind of gas pre-drainage boring ickings backfill method for sealing, while (1) utilizes drilling tool to coal bed drilling, coal dust is collected and filters or pulverize filtration, keep coal particle size to be not more than 1mm；(2) fine breeze after filtering inputs in agitator and adds cement and duff compound is made in white glue with vinyl stirring, and the weight percent composition of this each composition of duff compound is: fine breeze 60～70%, cement 25～35%, white glue with vinyl 4～6%；(3) adding water and continue stirring, making water and duff compound ratio is 0.3～0.5；(4) utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device, described injection hole sealing device includes gas drainage pipe and forward and backward pouch and Grouting Pipe, before and after's pouch it is respectively fixed with before and after the body of gas drainage pipe, in each pouch, run through connection have Grouting Pipe, described Grouting Pipe is by arm and pouch inner space, and is provided with check valve on arm；It is provided with explosive valve on slip casting tube wall between adjacent two pouches.The described each composition by weight percent of duff compound is preferred: fine breeze 65～70%, cement 27～30%, white glue with vinyl 5～6%, further preferably: fine breeze 68%, cement 27%, white glue with vinyl 5%.Water and duff compound ratio are 0.4.At least provided with a constraint lasso outside each pouch.Described gas drainage pipe inner terminal is provided with gas collecting segment, and bar shaped or circular air-vent are distributed on this gas collecting segment.
Fine breeze or cement use dosing device to be transfused in agitator, described dosing device includes that the tubular feed bin of an accumbency and an accumbency are installed on the rotating cylinder in this tubular feed bin, the upper and lower of tubular feed bin is respectively arranged with charging aperture and discharging opening, being provided with blade on the sidewall of rotating cylinder, the outline of each blade mates with tubular feed bin inwall.Owing to impeller clearance is quantitative gap, may insure that the specific material of release every time by arranging the dosing device of different model.
Described dosing device manually drive shaft rotates；Or the rotating shaft of rotating cylinder is in transmission connection with actuating unit.The output shaft of actuating unit is connected with the rotating shaft of rotating cylinder, is provided with the controlling organization changing actuating unit rotating speed.
Another kind of gas pre-drainage boring ickings backfill method for sealing, while (1) utilizes drilling tool to coal bed drilling, is collected and filters or pulverize filtration, keep coal particle size to be not more than 1mm coal dust；(2) fine breeze after filtering inputs in agitator and adds white glue with vinyl stirring makes duff compound, and the weight percent composition of this each composition of duff compound is: fine breeze 80～92%, white glue with vinyl 8～20%, and duff compound is made in stirring；(3) adding water and continue stirring, making water and duff compound ratio is 0.3～0.5；Duff slurry is made in stirring；(4) utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device, described injection hole sealing device includes gas drainage pipe and forward and backward pouch and Grouting Pipe, before and after's pouch it is respectively fixed with before and after the body of gas drainage pipe, in each pouch, run through connection have Grouting Pipe, described Grouting Pipe is by arm and pouch inner space, and is provided with check valve on arm；It is provided with explosive valve on slip casting tube wall between adjacent two pouches.The described each composition by weight percent of duff compound is preferred: fine breeze 90%, white glue with vinyl 10%.
Beneficial effect: the present invention utilizes fine breeze as sealing material, can gather materials on the spot, reduces cost of winning, allocates simple and convenient, determine that sealing of hole effect is the best through test of many times.The present invention utilizes duff slurry to replace cement mortar, carries out sealing of hole, and coal slurry is tightly combined with coal body, and coal body is not polluted by ungauged regions.And the foreign material such as too many cement sandstone will not be remained after working seam, exploitation purity is high, and production efficiency is high, is especially suitable for promotion and implementation.
Accompanying drawing explanation
Fig. 1 is one of schematic flow sheet of method for sealing of the present invention；
Fig. 2 is the two of the schematic flow sheet of method for sealing of the present invention；
Fig. 3 is the surface structure schematic diagram of injection hole sealing device in the present invention；
Fig. 4 is the cross-sectional view of Fig. 3；
Fig. 5 is the structural representation of dosing device in the present invention.
In figure, label 1 is gas drainage pipe, and 2 is pouch, and 3 are about collar circle, and 4 is Grouting Pipe, and 5 is explosive valve, and 6 is gas collecting segment, 7 is check valve, and 8 is agitator, and 9 is grouting pump, and 10 is valve, and 11 is the tubular feed bin of accumbency, 12 is charging aperture, and 13 is discharging opening, and 14 is rotating cylinder, and 15 is rotating shaft, and 16 is blade.
Detailed description of the invention
Embodiment 1: a kind of gas pre-drainage boring ickings backfill method for sealing, sees Fig. 1, while utilizing drilling tool to coal bed drilling, coal dust is collected and filters or pulverize filtration, keep coal particle size to be not more than 1mm；Then, the fine breeze after filtering inputs in agitator and adds cement and duff compound is made in white glue with vinyl stirring.
The each raw material making fine breeze compound can use dosing device or quantitative liquid feeding apparatus.Wherein quantitative liquid feeding body device can use Valve controlling, and dosing device can use structure as described in Figure 5.In Fig. 5, dosing device includes that the tubular feed bin 11 of an accumbency and an accumbency are installed on the rotating cylinder 14 in this tubular feed bin, the upper and lower of tubular feed bin 11 is respectively arranged with charging aperture 12 and discharging opening 13, being provided with blade 16 on the sidewall of rotating cylinder 14, the outline of each blade 16 mates with tubular feed bin 11 inwall.Owing to impeller clearance is quantitative gap, may insure that the specific material of release every time by arranging the dosing device of different model.
Described dosing device can manually drive shaft 15 rotate；Controllable ration feeding device can also be become, will the rotating shaft 15 of rotating cylinder 14 be in transmission connection with actuating unit.The output shaft of actuating unit is connected with the rotating shaft 15 of rotating cylinder, is provided with the controlling organization changing actuating unit rotating speed.
The weight percent composition of each composition of duff compound: add following weight percent composition in the agitator 8 in Fig. 3: fine breeze 60～70%, cement 25～35%, white glue with vinyl 4～6%, duff compound is made in stirring；Adding water and continue stirring, making water and duff compound ratio is 0.3～0.5.
Such as Fig. 3 and Fig. 4, utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device.The body of gas drainage pipe 1 is fixed with forward and backward pouch 2 successively, between the pouch 2 at gas drainage pipe 1 two ends, is divided into 3m ~ 15m spacing mutually.Running through connection in each pouch 2 and have Grouting Pipe 4, described Grouting Pipe 4 is by arm and pouch 2 inner space, and is provided with check valve 7 on arm, and Grouting Pipe 4 end fixing seal is in the pouch 2 of rear side；It is provided with explosive valve 5 on slip casting tube wall between adjacent two pouches 2；Two binding constraint lassos 3 of each suit outside each pouch 2.The explosive valve 5 on slip casting tube wall between adjacent two pouches 2, explosion at once when grouting pressure increases to 0.5MPa, after two explosive valves 5 explosion in the middle of gear, serosity enter before and after space between pouch 2, carry out the sealing of hole that pressurizes.It addition, gas drainage pipe 4 inner terminal is provided with gas collecting segment 6, on this gas collecting segment 6, bar shaped or circular air-vent are distributed.
Embodiment 2: content is substantially the same manner as Example 1, something in common does not repeats, except for the difference that: each composition by weight percent of duff compound: fine breeze 65～70%, cement 27～30%, white glue with vinyl 5～6%.Adding water and continue stirring, making water and duff compound ratio is 0.4～0.5.
Embodiment 3: content is substantially the same manner as Example 2, something in common does not repeats, except for the difference that: fine breeze 68%, cement 27%, white glue with vinyl 5%.Adding water and continue stirring, making water and duff compound ratio is 0.4.
Embodiment 4: another kind of gas pre-drainage boring ickings backfill method for sealing, sees Fig. 2, while utilizing drilling tool to coal bed drilling, coal dust is collected and filters or pulverize filtration, keep coal particle size to be not more than 1mm；Then, the fine breeze after filtering inputs in agitator and adds cement and duff compound is made in white glue with vinyl stirring.
The each raw material making fine breeze compound can use dosing device or quantitative liquid feeding apparatus.Wherein quantitative liquid feeding body device can use Valve controlling, and dosing device can use structure as described in Figure 5.In Fig. 5, dosing device includes that the tubular feed bin 11 of an accumbency and an accumbency are installed on the rotating cylinder 14 in this tubular feed bin, the upper and lower of tubular feed bin 11 is respectively arranged with charging aperture 12 and discharging opening 13, being provided with blade 16 on the sidewall of rotating cylinder 14, the outline of each blade 16 mates with tubular feed bin 11 inwall.Owing to impeller clearance is quantitative gap, may insure that the specific material of release every time by arranging the dosing device of different model.
Described dosing device can manually drive shaft 15 rotate；Controllable ration feeding device can also be become, will the rotating shaft 15 of rotating cylinder 14 be in transmission connection with actuating unit.The output shaft of actuating unit is connected with the rotating shaft 15 of rotating cylinder, is provided with the controlling organization changing actuating unit rotating speed.
The weight percent composition of each composition of duff compound: add following weight percent composition in the agitator 8 in Fig. 3: fine breeze 80～92%, white glue with vinyl 8～20%, duff compound is made in stirring；Adding water and continue stirring, making water and duff compound ratio is 0.3～0.5.
Such as Fig. 3 and Fig. 4, utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device.The body of gas drainage pipe 1 is fixed with forward and backward pouch 2 successively, between the pouch 2 at gas drainage pipe 1 two ends, is divided into 3m ~ 15m spacing mutually.Running through connection in each pouch 2 and have Grouting Pipe 4, described Grouting Pipe 4 is by arm and pouch 2 inner space, and is provided with check valve 7 on arm, and Grouting Pipe 4 end fixing seal is in the pouch 2 of rear side；It is provided with explosive valve 5 on slip casting tube wall between adjacent two pouches 2；Two binding constraint lassos 3 of each suit outside each pouch 2.The explosive valve 5 on slip casting tube wall between adjacent two pouches 2, explosion at once when grouting pressure increases to 0.5MPa, after two explosive valves 5 explosion in the middle of gear, serosity enter before and after space between pouch 2, carry out the sealing of hole that pressurizes.It addition, gas drainage pipe 4 inner terminal is provided with gas collecting segment 6, on this gas collecting segment 6, bar shaped or circular air-vent are distributed.
Utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device, described injection hole sealing device includes gas drainage pipe and forward and backward pouch and Grouting Pipe, before and after's pouch it is respectively fixed with before and after the body of gas drainage pipe, in each pouch, run through connection have Grouting Pipe, described Grouting Pipe is by arm and pouch inner space, and is provided with check valve on arm；It is provided with explosive valve on slip casting tube wall between adjacent two pouches.
Embodiment 5: content is substantially the same manner as Example 4, something in common does not repeats, except for the difference that: each composition by weight percent of duff compound is preferred: fine breeze 90%, white glue with vinyl 10%.Adding water and continue stirring, making water and duff compound ratio is 0.4.
Claims (10)
1. a gas pre-drainage boring ickings backfill method for sealing, is characterized in that: while (1) utilizes drilling tool to coal bed drilling, be collected coal dust and filter, and keeps coal particle size to be not more than 1mm；(2) fine breeze after filtering inputs in agitator and adds cement and duff compound is made in white glue with vinyl stirring, and the weight percent composition of this each composition of duff compound is: fine breeze 60～70%, cement 25～35%, white glue with vinyl 4～6%；(3) adding water and continue stirring, making water and duff compound ratio is 0.3～0.5, and duff slurry is made in stirring；(4) utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device, described injection hole sealing device includes gas drainage pipe and forward and backward pouch and Grouting Pipe, before and after's pouch it is respectively fixed with before and after the body of gas drainage pipe, in each pouch, run through connection have Grouting Pipe, described Grouting Pipe is by arm and pouch inner space, and is provided with check valve on arm；It is provided with explosive valve on slip casting tube wall between adjacent two pouches.
Gas pre-drainage the most according to claim 1 boring ickings backfill method for sealing, is characterized in that: the described each composition by weight percent of duff compound is: fine breeze 65～70%, cement 27～30%, white glue with vinyl 5～6%.
Gas pre-drainage the most according to claim 2 boring ickings backfill method for sealing, is characterized in that: fine breeze 68%, cement 27%, white glue with vinyl 5%；Water and duff compound ratio are 0.4.
Gas pre-drainage the most according to claim 1 boring ickings backfill method for sealing, is characterized in that: at least provided with a constraint lasso outside each pouch.
Gas pre-drainage the most according to claim 1 boring ickings backfill method for sealing, is characterized in that: described gas drainage pipe inner terminal is provided with gas collecting segment, bar shaped or circular air-vent is distributed on this gas collecting segment.
Gas pre-drainage the most according to claim 1 boring ickings backfill method for sealing, it is characterized in that: fine breeze or cement use dosing device to be transfused in agitator, described dosing device includes that the tubular feed bin of an accumbency and an accumbency are installed on the rotating cylinder in this tubular feed bin, the upper and lower of tubular feed bin is respectively arranged with charging aperture and discharging opening, being provided with blade on the sidewall of rotating cylinder, the outline of each blade mates with tubular feed bin inwall.
Gas pre-drainage the most according to claim 6 boring ickings backfill method for sealing, is characterized in that: described dosing device manually drive shaft rotates；Or the rotating shaft of rotating cylinder is in transmission connection with actuating unit.
Gas pre-drainage the most according to claim 7 boring ickings backfill method for sealing, is characterized in that: the output shaft of actuating unit is connected with the rotating shaft of rotating cylinder, is provided with the controlling organization changing actuating unit rotating speed.
9. a gas pre-drainage boring ickings backfill method for sealing, is characterized in that: while (1) utilizes drilling tool to coal bed drilling, be collected coal dust and filter, and keeps coal particle size to be not more than 1mm；(2) fine breeze after filtering inputs in agitator and adds white glue with vinyl stirring makes duff compound, and the weight percent composition of this each composition of duff compound is: fine breeze 80～92%, white glue with vinyl 8～20%, and duff compound is made in stirring；(3) adding water and continue stirring, making water and duff compound ratio is 0.3～0.5；Duff slurry is made in stirring；(4) utilize grouting pump by the grouting port of duff slurry conveying press-in injection hole sealing device, described injection hole sealing device includes gas drainage pipe and forward and backward pouch and Grouting Pipe, before and after's pouch it is respectively fixed with before and after the body of gas drainage pipe, in each pouch, run through connection have Grouting Pipe, described Grouting Pipe is by arm and pouch inner space, and is provided with check valve on arm；It is provided with explosive valve on slip casting tube wall between adjacent two pouches.
Gas pre-drainage the most according to claim 9 boring ickings backfill method for sealing, is characterized in that: the described each composition by weight percent of duff compound is preferred: fine breeze 90%, white glue with vinyl 10%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410051006.1A CN103790546B (en) | 2014-02-14 | 2014-02-14 | Gas pre-drainage boring ickings backfill method for sealing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410051006.1A CN103790546B (en) | 2014-02-14 | 2014-02-14 | Gas pre-drainage boring ickings backfill method for sealing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103790546A CN103790546A (en) | 2014-05-14 |
| CN103790546B true CN103790546B (en) | 2016-08-17 |
Family
ID=50666558
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410051006.1A Expired - Fee Related CN103790546B (en) | 2014-02-14 | 2014-02-14 | Gas pre-drainage boring ickings backfill method for sealing |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103790546B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106289716A (en) * | 2016-08-12 | 2017-01-04 | 河南理工大学 | A kind of gas-lift reverses circulation pneumatic conveying experiment device |
| CN109915070A (en) * | 2019-04-09 | 2019-06-21 | 中国矿业大学(北京) | The down-hole coal bed test gas pressure hole sealing device of one kind and method |
| CN111794682A (en) * | 2020-08-03 | 2020-10-20 | 河南理工大学 | Passive extrusion type pulse coal dust jet flow coal breaking pressure relief and permeability increasing device and using method thereof |
| CN115559685B (en) * | 2022-10-20 | 2023-06-30 | 中国矿业大学(北京) | Device and method for preparing and sealing coal-based composite hole sealing material in real time in drilling process |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4102397A (en) * | 1977-03-07 | 1978-07-25 | In Situ Technology, Inc. | Sealing an underground coal deposit for in situ production |
| CN101050696B (en) * | 2007-05-10 | 2010-05-19 | 河南理工大学 | Bag type paste injection hole sealing device and its hole sealing method |
| CN103015946A (en) * | 2012-12-26 | 2013-04-03 | 中煤科工集团重庆研究院 | Hole-drilling and hole-sealing method for gas extraction |
| CN203081397U (en) * | 2013-05-14 | 2013-07-24 | 平顶山市安泰华矿用安全设备制造有限公司 | Grouting bag type hole packer |
| CN103541663B (en) * | 2013-09-23 | 2016-07-06 | 中国平煤神马能源化工集团有限责任公司天成实业分公司 | Special three hole pipe and the usings method thereof of stopper |
-
2014
- 2014-02-14 CN CN201410051006.1A patent/CN103790546B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN103790546A (en) | 2014-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103775024B (en) | Duff slurry method for sealing | |
| CN103790546B (en) | Gas pre-drainage boring ickings backfill method for sealing | |
| CN105507938B (en) | Hydraulic flushing in hole combines the construction method of anti-reflection extraction system with presplit blasting in drilling | |
| CN103775120B (en) | A kind of up mash gas pumping drilling drilling cuttings method for sealing | |
| CN103195431B (en) | Slag tapping system and method for full face tunnel boring machine of deep vertical shaft | |
| CN103306719B (en) | Coal mine underground drilled hole filling and reinforcing device and method | |
| CN106761754A (en) | A kind of girdle comprehensive mining and gas control network one cooperative control system and method | |
| CN105240048A (en) | Air filling method based on paste filling | |
| CN204571912U (en) | Water filling hole sealing device | |
| CN203626720U (en) | Anti-spray orifice multi-section bag hole packer | |
| CN103758486A (en) | Pipeless grouting hole sealing device | |
| CN203742542U (en) | Non-pipe grouting hole sealing device | |
| CN104763467B (en) | Obturation and its placement method and system for Hazard in Deep Metal Mines goaf | |
| CN112610271B (en) | Drilling tank slurry backfilling device and method for coal mining subsidence area treatment | |
| CN102808624B (en) | Bastard coal is with extraction system and method | |
| CN113460562A (en) | Method for sealing coal-electricity fly ash in abandoned mined-out space of coal mine | |
| CN105971553A (en) | Portable gas drilling hole-sealing device and using method thereof | |
| CN205297636U (en) | Anti -reflection drainage system in coal seam in drilling | |
| CN105735939B (en) | Mash gas extraction backfills pouch slip casting type hole packer and application method with drilling cuttings | |
| CN205743827U (en) | Mash gas extraction drilling cuttings backfills pouch slip casting type hole packer | |
| CN207774364U (en) | A kind of deep-sea ores lifting system storage bin with material guide device | |
| CN211081960U (en) | Coal mine underground bottom suction roadway cross-layer drilling dredging device | |
| CN203230579U (en) | Pulp feed pump of hole sealing pump for coal mine | |
| CN211900690U (en) | Paste filling and mining complete equipment | |
| CN204163685U (en) | Integration mine pneumatic injection hole sealing equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB03 | Change of inventor or designer information |
Inventor after: Li Hui Inventor after: Wei Jianping Inventor before: Li Hui |
|
| COR | Change of bibliographic data | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Application publication date: 20140514 Assignee: Shanxi Ping Mei Mei solid mining materials Co., Ltd. Assignor: Henan Polytechnic University Contract record no.: 2017410000005 Denomination of invention: Gas pre-pumping drilled hole coal dust backfill sealing method Granted publication date: 20160817 License type: Common License Record date: 20170317 |
|
| EE01 | Entry into force of recordation of patent licensing contract | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160817 Termination date: 20210214 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |