AU2021447461A1 - Extra-thick coal seam upper layer old goaf roof reconstruction method and construction method - Google Patents
Extra-thick coal seam upper layer old goaf roof reconstruction method and construction method Download PDFInfo
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- AU2021447461A1 AU2021447461A1 AU2021447461A AU2021447461A AU2021447461A1 AU 2021447461 A1 AU2021447461 A1 AU 2021447461A1 AU 2021447461 A AU2021447461 A AU 2021447461A AU 2021447461 A AU2021447461 A AU 2021447461A AU 2021447461 A1 AU2021447461 A1 AU 2021447461A1
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- 239000003245 coal Substances 0.000 title claims abstract description 54
- 238000010276 construction Methods 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000005553 drilling Methods 0.000 claims abstract description 45
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000011268 mixed slurry Substances 0.000 claims description 24
- 239000004568 cement Substances 0.000 claims description 16
- 230000005484 gravity Effects 0.000 claims description 13
- 239000004576 sand Substances 0.000 claims description 13
- 239000010881 fly ash Substances 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 12
- 238000004140 cleaning Methods 0.000 claims description 8
- 239000012530 fluid Substances 0.000 claims description 7
- 238000005065 mining Methods 0.000 abstract description 20
- 230000009977 dual effect Effects 0.000 abstract 1
- 239000002002 slurry Substances 0.000 description 8
- 239000011435 rock Substances 0.000 description 7
- 238000009825 accumulation Methods 0.000 description 5
- 230000035699 permeability Effects 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000002341 toxic gas Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 229940034610 toothpaste Drugs 0.000 description 2
- 239000000606 toothpaste Substances 0.000 description 2
- 238000007596 consolidation process Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
- E21F15/005—Methods or devices for placing filling-up materials in underground workings characterised by the kind or composition of the backfilling material
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/70—Grouts, e.g. injection mixtures for cables for prestressed concrete
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Geochemistry & Mineralogy (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Structural Engineering (AREA)
- Materials Engineering (AREA)
- Road Paving Structures (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
- Conveying And Assembling Of Building Elements In Situ (AREA)
- Roof Covering Using Slabs Or Stiff Sheets (AREA)
Abstract
Disclosed is an extra-thick coal seam upper layer old goaf roof reconstruction method. The method comprises: step 1, providing roadway filling holes (2), wherein the roadway filling holes are provided along a center line of the extension of a roadway (1) with a spacing of 80-100 m therebetween, and the distance between the roadway filling holes and an end of the roadway is not larger than 20 m, and after drilling of the roadway filling holes, the roadway filling holes are filled, and the filling comprises aggregate pouring and grouting; and step 2, providing goaf filling holes, wherein the goaf filling holes are provided at intervals in a row as a unit in a manner in which holes of adjacent rows are staggered with a spacing of 40-60 m between the holes, and a spacing of 20-30 m between rows, and a row of goaf filling holes are filled after being drilled, and the filling comprises aggregate pouring and grouting. Further disclosed is an extra-thick coal seam upper layer old goaf roof reconstruction construction method. According to the extra-thick coal seam upper layer old goaf roof reconstruction method and construction method, hole drilling is conducted on the ground within the range of the roadway and a goaf (3) of an old goaf, and cavities in the roadway and the goaf are filled by means of aggregate pouring and pressurized grouting, such that the dual goals of roof reconstruction and water and gas hidden danger treatment are achieved, thereby providing a safety guarantee for lower layer coal mining.
Description
Method for reconstructing old goaf roof on upper layer of extra-thick
coal seam and construction method thereof
Technical Field
The present invention relates to the technical field of coal mining, more
particularly, to a method for reconstructing an old goaf roof on an upper layer of an
extra-thick coal seam and a construction method thereof.
Background
Coal is the backbone of non-renewable energy, and maximizing the recovery rate
and achieving safe and efficient coal mining are essential for China's energy security
system construction and the implementation of the sustainable development strategy.
Due to historical reasons, in some mining areas of China, some small coal mine
operators cast their eyes on the areas with abundant reserves, with high-quality coal,
and with little mining difficulty, but abandoned the lean areas and the areas with
inferior coal or with large mining difficulty, and they mined on the top, but abandoned
the bottom. Such mining methods have caused serious damage to the integrity of coal
seams, resulting in a large amount of waste of coal resources. According to incomplete
statistics, the reserves of abandoned coal resources nationwide are about 120 billion
tons, and the recoverable reserves are about 40.3 billion tons, which is a huge number,
and re-mining of abandoned coal will increase China's recoverable reserves by 30%,
where the abandoned resources in thick coal seams are widely distributed. There are
abundant reserves in China's thick coal seams, and thick (greater than 3.5m in coal
thickness) and extra thick coal seams (greater than 8m in coal thickness) are the
dominant coal seams for productive and efficient mining in China's coal mines, with
the reserves accounting for 45% of China. In recent years, with the integration of coal
resources, abandoned resources in thick coal seams have become the main mining
targets for resource-integration mines. After resource integration, thick coal seams are generally mined by means of fully mechanized caving. With the advancement of surrounding rock control theory, fully mechanized caving technology and equipment in terms of the high mining height of ultra-thick coal seams, the technical difficulties of supporting large cross-section coal tunnels and ensuring the safety of working faces under complex conditions have been solved, which can achieve safe and efficient mining at 14-20m ultra-thick coal seams. In order to implement the coal industry policy of improving resource utilization and mine the coal resources in the lower layer, it is necessary to reopen the closed mining areas and mine the coal in the lower layer.
However, the current status of water contamination, toxic gas accumulation, and roof
collapse in the goaf remains uncertain. Reopening may lead to water inrush, fire
hazards, poisoning, and collapses, presenting immense risks. It is necessary to fill old
goaf areas and tunnels to remove water and toxic gases and consolidate the fractured
rock strata, thus providing a geological support for the mining of coal resources in the
lower layer.
Summary of the Invention
The present invention provides a method for reconstructing an old goaf roof on
an upper layer of an extra-thick coal seam, which solves the problems of water and gas
accumulation, roof collapse and fragmentation in the closed goaf after the upper layer
of the ultra-thick coal seam has been mined, as well as the problems of water inrush,
fire, and collapse after reopening. In the present invention, the goaf and roadway are
filled for reinforcement by drilling holes, thus controlling the water and toxic gases in
the upper layer of the goaf, reconstructing the roof, and ensuring the safety of coal
mining in the lower layer.
To achieve the above objective, the present invention proposes the following
technical solution:
A method for reconstructing an old goaf roof on an upper layer of an extra-thick
coal seam, comprising: step 1: arranging roadway filling holes along a centerline of the roadway at intervals of 80-100m, wherein the roadway filling holes are not more than 20m from ends of the roadway; filling the roadway filling holes after being drilled, the filling comprising aggregate pouring and grouting; step 2: arranging goaf filling holes at intervals by the row in such a manner that goaf filling holes of adjacent rows are staggered with a hole spacing of 40-60 m and a row spacing of 20-30 m, wherein a row of goaf filling holes are filled immediately after the row of goaf filling holes are drilled, and the filling comprises grouting and/or aggregate pouring.
Optionally, the filling of the roadway filling holes comprises:
aggregate pouring: pouring aggregate at a water flow rate of 60-100m 3/h,
wherein a mass ratio of sand to gangue in the aggregate is 1: 1, or single aggregate is
selected, a particle size of sand is 0.2-0.5mm, a particle size of gangue is 5-15mm, a
mass ratio of water to aggregate is 12-8: 1, and the pouring is stopped when a negative
pressure is less than 0.04 MPa;
grouting: after completion of aggregate pouring, cleaning drill-holes to the
roadway, injecting a mixed slurry of P.032.5 cement and secondary fly ash at a mass
ratio of 5: 5 or 6: 4, wherein specific gravity of the mixed slurry is 1.4-1.7 and a grouting
flow rate is 400-250L/min, then reducing the grouting flow rate to 40-60L/min after an
orifice pressure reaches 1.0-1.5MPa, and stopping the grouting after the pressure has
been stabilized for 15-20 minutes.
Optionally, the filling of goaf filling holes comprises:
the goaf filling holes comprising goaf-filling primary holes and goaf-filling
secondary holes, wherein the goaf-filling primary holes and goaf-filling secondary
holes of adjacent rows are staggered at intervals; arranging a column of goaf-filling secondary holes as discharge holes at intervals of 150-200m along the goaf, and then filling progressively from low to high and from a mining-stop line to an open-off cut; grouting: every 10-15m drilled is a grouting section; injecting a mixed slurry of cement and fly ash at a mass ratio of 7: 3 or 6: 4, wherein specific gravity of the mixed slurry is 1.4-1.7, and a grouting flow rate is 400-250L/min, and reducing the grouting flow rate to 40-60L/min after an orifice pressure reaches 1.5-2.5MPa, and stopping the grouting after the pressure has been stabilized for 15-20 minutes; pouring aggregate when the consumption of drilling fluid is greater than 50m 3 /h or the grouting amount is greater than 40t/h.
Optionally, the filling is implemented by taking adjacent goaf-filling primary holes
and an intermediate goaf-filling secondary holes as an implementation unit;
the adjacent goaf-filling primary holes are filled first respectively and then the
intermediate goaf-filling secondary holes are filled.
Optionally, the diameter of the roadway filling hole is 311mm-215.9mm at the
beginning, and then the drilling goes to 10-15m above the roadway and mined-out
area, and the diameter of the roadway filling hole turns to 152mm-127mm at the time
of drilling through;
hole inclination of the roadway filling hole: the offset at the hole bottom is not
more than 2m, and the inclination is measured every 10-20m during the drilling.
A construction method for reconstructing an old goaf roof on an upper layer of
an extra-thick coal seam, comprising:
Si: construction of roadway filling holes;
arranging roadway filling holes along a centerline of the roadway at intervals of
-100m, wherein the roadway filling holes are not more than 20m from an end of the
roadway; filling the roadway filling holes after the roadway filling holes are drilled, the filling comprising aggregate pouring and grouting;
S2: construction of goaf filling holes;
arranging goaf filling holes at intervals by the row in such a manner that goaf
filling holes of adjacent rows are staggered with a hole spacing of 40-60 m and a row
spacing of 20-30 m, wherein a row of goaf filling holes are filled immediately after the
row of goaf filling holes are drilled, and the filling comprises grouting and aggregate
pouring.
Optionally, the filling of roadway filling holes comprises:
aggregate pouring: pouring aggregate at a water flow rate of 60-100m 3/h,
wherein a mass ratio of sand to gangue in the aggregate is 1: 1, or single aggregate is
selected, a particle size of sand is 0.2-0.5mm, a particle size of gangue is 5-15mm, a
mass ratio of water to aggregate is 12-8: 1, and the pouring is stopped when a negative
pressure is less than 0.04 MPa;
grouting: after completion of aggregate pouring, cleaning drill-holes to the
roadway, injecting a mixed slurry of P.032.5 cement and secondary fly ash at a mass
ratio of 5: 5 or 6: 4, wherein specific gravity of the mixed slurry is 1.4-1.7 and a grouting
flow rate is 400-250L/min, then reducing the grouting flow rate to 40-60L/min after an
orifice pressure reaches 1.0-1.5MPa, and stopping the grouting after the pressure has
been stabilized for 15-20 minutes.
Optionally, the filling of goaf filling holes comprises:
the goaf filling holes comprising goaf-filling primary holes and goaf-filling
secondary holes, wherein the goaf-filling primary holes and goaf-filling secondary
holes of adjacent rows are staggered at intervals; arranging a column of goaf-filling
secondary holes as discharge holes at intervals of 150-200m along the goaf, and then
filling progressively from low to high and from a mining-stop line to an open-off cut; grouting: every 10-15m drilled is a grouting section; injecting a mixed slurry of cement and flyash at a mass ratio of 7: 3 or6: 4, wherein a specific gravity of the mixed slurry is 1.4-1.7, and a grouting flow rate is 400-250L/min, and reducing the grouting flow rate to 40-60L/min after an orifice pressure reaches 1.5-2.5MPa, and stopping the grouting after the pressure has been stabilized for 15-20 minutes; pouring aggregate when the consumption of drilling fluid is greater than 50m 3/h or the grouting amount is greater than 40t/h.
Optionally, the diameter of the roadway filling hole is 311mm-215.9mm at the
beginning, and then the drilling goes to 10-15m above the roadway and the mined
out area, and the diameter of the roadway filling hole turns to 152mm-127mm at the
time of drilling through;
hole inclination of the roadway filling hole: the offset at the hole bottom is not
more than 2m, and the inclination is measured every 10-20m during the drilling;
casing depth: the casing goes down to 10-15m above the roadway roof and the
mined-out area;
construction sequence: each roadway is divided into N construction sections at
intervals of 400-500m, and for each construction section, the drilling-through in the
lowest position is completed first and the hole formed therefore is used as a discharge
hole, then the construction is carried out on the construction sections one by one from
low to high along the roadway, and the drilling in each construction section is
performed in a hole-skipping manner.
Optionally, the filling is implemented by taking adjacent goaf-filling primary holes
and an intermediate goaf -filling secondary hole as an implementation unit;
the adjacent goaf-filling primary holes are filled first respectively and then the
intermediate goaf-filling secondary holes are filled.
Compared with the prior art, the present invention has the following
advantageous effects:
In the present invention, holes are drilled from the ground within the range of
roadways and mined-out areas of the goaf, and the cavities in roadways and mined
out areas are filled by aggregate pouring and pressurized grouting to replace the water
and toxic gases in the cavities and consolidate the loose and broken rocks into a
complete body, thus achieving double goals of reconstructing the roof and controlling
the potential water and gas hazards, and ensuring the safety of coal mining in the
lower layer.
Brief Description of the Drawings
The accompanying drawings are provided for further understanding of the
present disclosure and constitute a part of the specification, and together with the
specific embodiments below, serve to explain the present disclosure, but do not
constitute a limitation of the present disclosure. In the drawings:
Fig. 1 is a plan view of holes drilled for roof reconstruction;
Fig. 2 is a sectional view of holes drilled for roof reconstruction in the goaf;
Fig. 3 is a schematic view of roadway filling; and
Fig. 4 is a schematic view of horizontal roadway filling.
1- roadway; 2-hole drilled for roadway filling; 3- goaf; 4- goaf-filling primary hole;
-goaf-filling secondary hole; 6-casing; 7-upper coal; 8-lower coal; 9-aggregate
accumulation body; 10-slurry filling body; 11-discharge hole; 12-access hole.
Detailed Description of the Embodiments
In the following, the technical solution in the embodiments of the present
invention will be described clearly and completely in conjunction with the drawings.
Obviously, the embodiments described below are only part and not all of the
embodiments of the present invention, and they do not limit the present invention in
any form. Any technical solution using the embodiments, including simple changes to
the embodiments, falls within the scope of protection of the present invention.
In order to further demonstrate the structural features and effects of the present
invention, preferred embodiments as well as the accompanying drawings are used to
give a detailed description.
The method for reconstructing an old goaf roof on an upper layer of an extra
thick coal seam according to the present invention comprises:
Step 1: Collecting geological and mining data, including stratum structure,
distribution and elevation of roadway 1, mining height and mining depth, and scope
and elevation of goaf 3.
Step 2: Determining the drilling position. The roadway filling holes 2 are arranged
along a centerline of the roadway 1 at intervals of 80-100m, and the holes are not
more than 20m from both ends of the roadway 1; goaf-filling primary holes 4 and goaf
filling secondary holes 5 of adjacent rows are staggered at intervals with a hole spacing
of 40-60 m and a row spacing of 20-30 m.
Step 3: Filling the roadway 1.
Borehole positioning: The accuracy requirement for measuring and setting out
the borehole orifice is that the error away from the designed coordinates is not more
than 1m.
Borehole diameter: it is 311mm-215.9mm at the beginning, then the drilling goes
to 10-15m above the roadway and the mined-out area, and the borehole diameter
turns to 152mm-127mm at the time of drilling through;
Borehole inclination: the offset at the hole bottom is not more than 2m, and the
O inclination is measured every 10-20m during the drilling. It ensures drilling through accurately to the roadway.
Casing depth: the casing 6 goes down to 10-15m above the roadway roof, with
the well cemented by cement.
Construction sequence: each roadway 1 is divided into N construction sections at
intervals of 400-500m, and for each construction section, the drilling-through in the
lowest position is carried out first and the hole formed therefore is used as a discharge
hole 11 for exhausting gas and draining water, then construction is carried out on the
construction sections one by one from low to high along the roadway 1, and the drilling
in each construction section is performed in a hole-skipping manner.
Drilling through: drilling through is carried out after the operation of the casing 6
is completed, and if drill bit drop, drilling break, or extensive leakage of drilling fluid
occurs, it indicates that the hole has been drilled through to the roadway.
Aggregate pouring: lifting out the drill rod after completing the drilling-through,
installing a negative pressure gauge, a pipeline and a funnel at the orifice, and pouring
by the water flow which carries aggregate; having a water injection test before pouring,
and meanwhile observing the water level of the discharge hole 11 to judge the
connectivity of the roadway 1; pouring the aggregate at a water flow rate of 60
100m 3/h, wherein a mass ratio of sand to gangue in the aggregate is 1: 1, or single
aggregate is selected, a particle size of sand is 0.2-0.5mm, a particle size of gangue is
-15mm, a mass ratio of waterto aggregate is (12:1) - (8: 1), and the pouring isstopped
when a negative pressure is less than 0.04 MPa. An aggregate accumulation body 9 is
formed in the roadway.
Grouting: after completion of aggregate pouring, cleaning drill-holes to the
roadway, injecting a mixed slurry of P.032.5 cement and secondary fly ash at a mass
ratio of 5: 5 or 6: 4, wherein specific gravity of the mixed slurry is 1.4-1.7 and a grouting
flow rate is 400-250L/min, then reducing the grouting flow rate to 40-60L/min after the orifice pressure reaches 1.0-1.5MPa, and stopping the grouting after the pressure has been stabilized for 15-20 minutes. A slurry filling body 10 is formed in the roadway.
Cementing: cleaning drill-holes after the completion of grouting, drilling to 1-2m
below the baseboard of the roadway 1, and pulling out for supplementary grouting
again; pure cement slurry is selected for the supplementary grouting.
The construction is carried out on the construction sections one by one from low
to high, until filling of the entire roadway 1 is completed.
Step 4: filling the goaf 3
After the roadway 1 is filled, the goaf 3 forms a closed space to avoid slurry loss.
At this time, the construction of goaf filling holes is started. The drilling is carried out
in two stages: goaf-filling primary holes 4 are drilled first, and then goaf-filling
secondary holes 5 are drilled. All the casings 6 go down to 10-15m above the goaf 3.
First a column of goaf-filling secondary holes 5 are drilled at intervals of 150-200m
along the goaf 3 as discharge holes, then the construction progresses from low to high
and from a mining-stop line to an open-off cut in a "toothpaste squeezing" manner.
Those whose working faces are long can be divided into multiple construction sections
over which the construction is carried out simultaneously. For example, the filling is
implemented by taking adjacent goaf-filling primary holes 4 and an intermediate goaf
filling secondary hole 5 as an implementation unit; the adjacent goaf-filling primary
holes 4 are filled first respectively and then the intermediate goaf-filling secondary
holes 5 are filled.
Length of grouting section: after entry into the goaf 3, every 10-15m drilled is
deemed as a grouting section.
Grouting: injecting a mixed slurry of cement and fly ash at a mass ratio of 7: 3 or
6: 4 in a "pure pressure type pure static pressure continuous grouting method with
grouting stopped by orifice", wherein a specific gravity of the mixed slurry is 1.4-1.7 and a grouting flow rate is 400-250L/min, then reducing the grouting flow rate to 40
L/min after the orifice pressure reaches 1.5-2.5MPa, and stopping the grouting after
the pressure has been stabilized for 15-20 minutes. In the case of a large grouting
amount or a large goaf gap, the aggregate is poured in the same way as in step 3.
Step 5: Constructing access holes 12: adding bore holes which account for 10%
% of the total of boreholes formed during construction and using them as access
holes. The permeability and strength of the filling body are checked by a simple water
pressure test and a rock core strength test. Inspection standard: the water
permeability in the water pressure test is less than 1Lu, and the saturated compressive
strength of the filling body rock core is 2-5MPa.
Embodiment 1
Step 1: Collecting geological and mining data. Fig. 1 is a plan view of the roadway
and mined-out area of the upper layer. The thickness of the coal seam is 9m, wherein
the upper layer 7 is 3m and has been mined, and the lower layer 8 is 6m and hasn't
been mined yet.
Step 2: Determining the drilling position, as shown in the figure. The roadway
filling holes 2 are arranged along a centerline of the roadway at intervals of 80m, and
the holes are 15m from both ends of the roadway 1; goaf-filling primary holes 4 and
goaf-filling secondary holes 5 of adjacent rows are staggered at intervals with a hole
spacing of 60 m and a row spacing of 30 m.
Step 3: Filling the roadway 1, as shown in Figs. 1, 3, and 4.
Borehole positioning: setting out and positioning the borehole according to the
designed coordinates of the borehole orifice, and the error away from the designed
coordinates is not more than 1m.
Drilling: the diameter of the borehole is 215.9mm at the beginning, and the drill penetrates to 10m above the top board of the roadway 1 and installing a
D177.8x8.05mm casing 6 into the borehole; after well cementing, the borehole is
drilled through to the roadway at a diameter of 152mm.
Borehole inclination: the offset at a hole bottom is not more than 2m, and the
inclination is measured every 20m during the drilling. The straight screw is provided to
produce vertical boreholes, and ensures drilling through accurately to the roadway.
Construction sequence: each roadway 1 is divided into N construction sections at
intervals of 400m, and for each construction section, the drilling-through in the lowest
position is completed first and the hole formed therefore is used as a discharge hole
11, then the construction is carried out on the construction sections one by one from
low to high along the roadway 1, and the drilling in each construction section is
performed in a hole-skipping manner.
Drilling through: drilling-through is carried out after the operation of the casing 6
is completed, and if drill bit drop, drilling break, or extensive leakage of drilling fluid
occurs, it indicates that the hole has been drilled through to the roadway.
Aggregate pouring: lifting out the drill rod after completing the drilling-through,
installing a negative pressure gauge, a pipeline and a feeding funnel at the orifice, and
pouring bythe water flow which carries aggregate; having a water injection test before
pouring, and meanwhile observing the water level of the discharge hole 11 to judge
the connectivity of the roadway; pouring the aggregate at a waterflow rate of 100m 3/h,
wherein a mass ratio of sand to gangue in the aggregate is 1: 1, the sand is fine-medium
sand with a particle size of 0.2-0.5mm, the particle size of gangue is 5-15mm, the mass
ratio of water to aggregate is 10: 1, and the pouring is stopped when the negative
pressure is less than 0.04 MPa. An aggregate accumulation body 9 is formed in the
roadway.
Grouting: after completion of aggregate pouring, cleaning drill-holes to the
roadway 1, injecting a mixed slurry of P.032.5 cement and secondary fly ash at a mass ratio of 5: 5, wherein specific gravity of the mixed slurry is 1.7 and a grouting flow rate is 400L/min, then reducing the grouting flow rate to 52L/min after the orifice pressure reaches 1.5MPa, and stopping the grouting after the pressure has been stabilized for minutes. A slurry filling body 10 is formed in the roadway.
Consolidation: cleaning drill-holes after the completion of grouting, drilling to 2m
below the baseboard of the roadway 1, and pulling out for supplementary grouting
again; pure cement slurry is selected for the supplementary grouting, wherein the
specific gravity of the pure cement slurry is 1.7 and the grouting flow rate is 250L/min,
then reducing the grouting flow rate to 52L/min after the orifice pressure reaches
1.5MPa, and stopping the grouting after the pressure has been stabilized for 15
minutes.
The construction is carried out on construction sections one by one from low to
high, until all filling of the roadway 1is completed.
Step 4: filling the goaf 3, as shown in Figs. 1-2
After the roadway 1 is filled, the goaf 3 forms a closed space to avoid slurry loss.
At this time, the construction of goaf filling holes is started. The drilling is made in two
stages, and the drilling casing 6 goes down to 10m above the goaf 3.
First a column of goaf-filling secondary holes 5 are drilled at intervals of 200m
along the goaf as discharge holes, then the construction progresses from low to high
and from a mining-stop line to an open-off cut in a "toothpaste squeezing" manner.
Goaf-filling primary holes 4 are drilled first, and then goaf-filling secondary holes 5 are
drilled, and the sections between primary holes are checked and consolidated.
Length of grouting section: after entry into the goaf 3, every 10m drilled is
deemed as a grouting section.
Grouting: injecting a mixed slurry of cement and fly ash at a mass ratio of 6: 4 in a "pure-pressure type static pressure continuous grouting method with grouting stopped by orifice", wherein a specific gravity of the mixed slurry is 1.7 and a grouting flow rate is 300L/min, then reducing the grouting flow rate to 52L/min after the orifice pressure reaches 1.5MPa, and stopping the grouting after the pressure has been stabilized for 15 minutes. When the grouting amount is greater than 40t/h or the consumption of drilling fluid in the goaf is greater than 50m 3 /h, the aggregate is poured in the same way as in step 3.
Step 5: Constructing access holes 12: adding boreholes which account for 10% of
the total of boreholes made during construction and using them as access holes 12.
The permeability and strength of the filling body are checked by a simple water
pressure test and a rock core strength test. Upon inspection, the water permeability
in the water pressure test is all less than 1Lu, and the saturated compressive strength
of the filling body rock cores is all greater than 2MPa.
The preferred embodiments of the present disclosure are described in detail
above in conjunction with the accompanying drawings. However, the present
disclosure is not limited to the specific details of the aforementioned embodiments.
The technical solution of the present disclosure may have multiple simple variations
within the scope of technical concept of the present disclosure, all of which fall within
the scope of protection of the present disclosure.
Furthermore, it should be noted that the technical features described in the
above embodiments, if not contradicting with each other, can be combined in any
suitable way. To avoid unnecessary repetition, the present disclosure will not describe
the possible combinations.
The embodiments of the present disclosure can also be combined arbitrarily. As
long as the combinations do not violate the idea of the present disclosure, they should
also be considered as being disclosed by the present disclosure.
Claims (10)
1. A method for reconstructing an old goaf roof on an upper layer of an extra
thick coal seam, characterized by comprising:
step 1: arranging roadway filling holes along a centerline of a roadway at intervals
of 80-100m, wherein the roadway filling holes are not more than 20m from ends of
the roadway; filling the roadway filling holes after being drilled, the filling comprising
aggregate pouring and grouting;
step 2: arranging goaf filling holes at intervals by the row in such a manner that
goaf filling holes of adjacent rows are staggered with a hole spacing of 40-60 m and a
row spacing of 20-30 m, wherein a row of goaf filling holes are filled immediately after
the row of goaf filling holes are drilled, and the filling comprises grouting and/or
aggregate pouring.
2. The method for reconstructing an old goaf roof on an upper layer of an extra
thick coal seam according to claim 1, characterized in that the filling of the roadway
filling holes comprises:
aggregate pouring: pouring aggregate at a water flow rate of 60-100m 3/h,
wherein a mass ratio of sand to gangue in the aggregate is 1: 1, or single aggregate is
selected, a particle size of sand is 0.2-0.5mm, a particle size of gangue is 5-15mm, a
mass ratio of water to aggregate is 12-8: 1, and the pouring is stopped when a negative
pressure is less than 0.04 MPa;
grouting: after completion of aggregate pouring, cleaning drill-holes to the
roadway, injecting a mixed slurry of P.032.5 cement and secondary fly ash at a mass
ratio of 5: 5 or 6: 4, wherein a specific gravity of the mixed slurry is 1.4-1.7 and a
groutingflow rate is400-250L/min, then reducing the grouting flow rate to40-60L/min
after an orifice pressure reaches 1.0-1.5MPa, and stopping the grouting after the pressure has been stabilized for 15-20 minutes.
3. The method for reconstructing an old goaf roof on an upper layer of an extra
thick coal seam according to claim 1 or 2, characterized in that the filling of goaf filling
holes comprises:
the goaf filling holes comprising goaf-filling primary holes and goaf-filling
secondary holes, wherein the goaf-filling primary holes and goaf-filling secondary
holes of adjacent rows are staggered at intervals; arranging a column of goaf-filling
secondary holes as discharge holes at intervals of 150-200m along the goaf, and then
filling progressively from low to high and from a mining-stop line to an open-off cut;
grouting: every 10-15m drilled is a grouting section; injecting a mixed slurry of
cement and fly ash at a mass ratio of 7: 3 or 6: 4, wherein a specific gravity of the mixed
slurry is 1.4-1.7, and a grouting flow rate is 400-250L/min, and reducing the grouting
flow rate to 40-60L/min after an orifice pressure reaches 1.5-2.5MPa, and stopping the
grouting after the pressure has been stabilized for 15-20 minutes; pouring aggregate
when the consumption of drilling fluid is greater than 50m 3 /h or the grouting amount
is greater than 40t/h.
4. The method for reconstructing an old goaf roof on an upper layer of an extra
thick coal seam according to claim 3, characterized in that the filling is implemented
by taking adjacent goaf-filling primary holes and an intermediate goaf-filling secondary
hole as an implementation unit;
the adjacent goaf-filling primary holes are filled first respectively and then the
goaf-filling secondary holes are filled.
5. The method for reconstructing an old goaf roof on an upper layer of an extra
thick coal seam according to claim 1 or 2, characterized in that the diameter of the
roadway filling hole is 311mm-215.9mm at the beginning, and then the drilling goes
to 10-15m above the roadway and the mined-out area, and the diameter of the roadway filling hole turns to 152mm-127mm at the time of drilling through; hole inclination of the roadway filling hole: the offset at the hole bottom is not more than 2m, and the inclination is measured every 10-20m during the drilling.
6. A construction method for reconstructing an old goaf roof on an upper layer of
an extra-thick coal seam, characterized by comprising:
Si: construction of roadway filling holes;
arranging roadway filling holes along a centerline of the roadway at intervals of
-100m, wherein the roadway filling holes are not more than 20m from ends of the
roadway; filling the roadway filling holes after the roadway filling holes are drilled, the
filling comprising aggregate pouring and grouting;
S2: construction of goaf filling holes;
arranging goaf filling holes at intervals by the row in such a manner that goaf
filling holes of adjacent rows are staggered with a hole spacing of 40-60 m and a row
spacing of 20-30 m, wherein a row of goaf filling holes are filled immediately after the
row of goaf filling holes are drilled, and the filling comprises grouting and aggregate
pouring.
7. The construction method for reconstructing an old goaf roof on an upper layer
of an extra-thick coal seam according to claim 6, characterized in that the filling of
roadway filling holes comprises:
aggregate pouring: pouring aggregate at a water flow rate of 60-100m 3/h,
wherein a mass ratio of sand to gangue in the aggregate is 1: 1, or single aggregate is
selected, a particle size of sand is 0.2-0.5mm, a particle size of gangue is 5-15mm, a
mass ratio of water to aggregate is 12-8: 1, and the pouring is stopped when a negative
pressure is less than 0.04 MPa; grouting: after completion of aggregate pouring, cleaning drill-holes to the roadway, injecting a mixed slurry of P.032.5 cement and secondary fly ash at a mass ratio of 5: 5 or 6: 4, wherein a specific gravity of the mixed slurry is 1.4-1.7 and a groutingflow rate is400-250L/min, then reducing the grouting flow rate to40-60L/min after an orifice pressure reaches 1.0-1.5MPa, and stopping the grouting after the pressure has been stabilized for 15-20 minutes.
8. The construction method for reconstructing an old goaf roof on an upper layer
of an extra-thick coal seam according to claim 6 or 7, characterized in that the filling of
goaf filling holes comprises:
the goaf filling holes comprising goaf-filling primary holes and goaf-filling
secondary holes, wherein the goaf-filling primary holes and goaf-filling secondary
holes of adjacent rows are staggered at intervals; arranging a column of goaf-filling
secondary holes as discharge holes at intervals of 150-200m along the goaf, and then
filling progressively from low to high and from a mining-stop line to an open-off cut;
grouting: every 10-15m drilled is a grouting section; injecting a mixed slurry of
cement and fly ash at a mass ratio of 7: 3 or 6: 4, wherein a specific gravity of the mixed
slurry is 1.4-1.7, and a grouting flow rate is 400-250L/min, and reducing the grouting
flow rate to 40-60L/min after an orifice pressure reaches 1.5-2.5MPa, and stopping the
grouting after the pressure has been stabilized for 15-20 minutes; pouring aggregate
when the consumption of drilling fluid is greater than 50m 3/h or the grouting amount
is greater than 40t/h.
9. The construction method for reconstructing an old goaf roof on an upper layer
of an extra-thick coal seam according to claim 6 or 7, characterized in that the diameter
of the roadway filling hole is 311mm-215.9mm at the beginning, and then the drilling
goes to 10-15m above the roadway and the mined-out area, and the diameter of the
roadway filling hole turns to 152mm-127mm at the time of drilling through;
hole inclination of the roadway filling hole: the offset at the hole bottom is not more than 2m, and the inclination is measured every 10-20m during the drilling; casing depth: the casing goes down to 10-15m above the roadway roof and the mined-out area; construction sequence: each roadway is divided into N construction sections at intervals of 400-500m, and for each construction section, the drilling-through in the lowest position is completed first and the hole formed therefore is used as a discharge hole, then the construction is carried out on the construction sections one by one from low to high along the roadway, and the drilling in each construction section is performed in a hole-skipping manner.
10. The construction method for reconstructing an old goaf roof on an upper layer
of an extra-thick coal seam according to claim 1 or 2, characterized in that the filling is
implemented by taking adjacent goaf-filling primary holes and an intermediate goaf
filling secondary holes as an implementation unit;
the adjacent goaf-filling primary holes are filled first respectively and then the
goaf-filling secondary holes are filled.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110589840.6A CN113279811B (en) | 2021-05-28 | 2021-05-28 | Reconstruction method and construction method for layered old goaf roof on super-thick coal seam |
| CN202110589840.6 | 2021-05-28 | ||
| PCT/CN2021/140958 WO2022247258A1 (en) | 2021-05-28 | 2021-12-23 | Extra-thick coal seam upper layer old goaf roof reconstruction method and construction method |
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| AU2021447461A1 true AU2021447461A1 (en) | 2023-10-19 |
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| AU2021447461A Pending AU2021447461A1 (en) | 2021-05-28 | 2021-12-23 | Extra-thick coal seam upper layer old goaf roof reconstruction method and construction method |
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| Country | Link |
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| CN (1) | CN113279811B (en) |
| AU (1) | AU2021447461A1 (en) |
| WO (1) | WO2022247258A1 (en) |
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| CN113279811B (en) * | 2021-05-28 | 2024-05-03 | 中煤科工集团西安研究院有限公司 | Reconstruction method and construction method for layered old goaf roof on super-thick coal seam |
| CN116771417A (en) * | 2021-10-29 | 2023-09-19 | 丛培杰 | Mine goaf slurry backfilling method for preventing groundwater pollution |
| CN114215590A (en) * | 2021-11-17 | 2022-03-22 | 中煤科工开采研究院有限公司 | Desk type grouting method suitable for high-space goaf |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB2177389A (en) * | 1985-07-01 | 1987-01-21 | Mitsubishi Mining & Cement Co | Filling and solidifying grout slurry in coal pit |
| CN202500606U (en) * | 2012-01-20 | 2012-10-24 | 山东大学 | Device for filling aggregate into formation cavity through ground surface borehole |
| CN103498696B (en) * | 2013-10-02 | 2015-08-05 | 中国矿业大学 | A kind of method from roadway in the roof grouting filling compacting goaf filling body |
| CN103742149B (en) * | 2014-01-22 | 2015-10-28 | 太原理工大学 | A kind of combining puts the method that second mining remains ground coal |
| CN103899351B (en) * | 2014-03-28 | 2016-05-04 | 中冶沈勘工程技术有限公司 | A kind of filling reinforcement means of processing complicated cavity |
| CN103924976B (en) * | 2014-04-04 | 2016-10-19 | 太原理工大学 | A kind of method in outdoor second mining Guo Canmei district |
| CN104153807B (en) * | 2014-07-04 | 2016-06-29 | 河南理工大学 | A kind of placement method of thick seam slicing system Coal Face Passing Through lower leaf old working |
| CN106368731A (en) * | 2016-11-16 | 2017-02-01 | 中国神华能源股份有限公司 | Goaf disposal method |
| CN109488301A (en) * | 2018-09-30 | 2019-03-19 | 中国矿业大学 | A kind of mine, which picks up, fills place's recovery method |
| CN110374600B (en) * | 2019-07-29 | 2020-07-14 | 中国矿业大学(北京) | Non-offset arrangement method for mining roadway of extremely-close coal seam group |
| CN110630321B (en) * | 2019-10-29 | 2024-05-17 | 中冶沈勘秦皇岛工程设计研究总院有限公司 | Goaf aboveground filling equipment and goaf aboveground filling method |
| CN111237010B (en) * | 2020-01-20 | 2021-05-18 | 中煤科工集团西安研究院有限公司 | Coal mine curtain grouting method |
| CN111577381A (en) * | 2020-05-11 | 2020-08-25 | 中铁第四勘察设计院集团有限公司 | Goaf filling structure and goaf treatment method |
| CN111794799A (en) * | 2020-07-16 | 2020-10-20 | 中煤天津设计工程有限责任公司 | Solid waste treatment technology for ground drilling, grouting and filling of old goaf |
| CN113279811B (en) * | 2021-05-28 | 2024-05-03 | 中煤科工集团西安研究院有限公司 | Reconstruction method and construction method for layered old goaf roof on super-thick coal seam |
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