U.S. patent application number 15/864740 was filed with the patent office on 2018-07-12 for mining underground formations.
The applicant listed for this patent is Seneca Industries Inc.. Invention is credited to Michael Cline, John Dickinson, Timothy J. Myers.
Application Number | 20180195390 15/864740 |
Document ID | / |
Family ID | 62782767 |
Filed Date | 2018-07-12 |
United States Patent
Application |
20180195390 |
Kind Code |
A1 |
Dickinson; John ; et
al. |
July 12, 2018 |
MINING UNDERGROUND FORMATIONS
Abstract
Mining systems include a continuous miner; a movable roof
support; a roof bolter; and a flexible conveyor train positioned
with its front end located under the roof support and extending
underneath the roof bolter.
Inventors: |
Dickinson; John; (Palm Beach
Gardens, FL) ; Myers; Timothy J.; (Beckley, WV)
; Cline; Michael; (Carlinville, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Seneca Industries Inc. |
Beckley |
WV |
US |
|
|
Family ID: |
62782767 |
Appl. No.: |
15/864740 |
Filed: |
January 8, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62444298 |
Jan 9, 2017 |
|
|
|
62511229 |
May 25, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21D 23/0472 20130101;
E21D 23/081 20130101; E21C 27/24 20130101; E21D 23/10 20130101;
E21D 23/0086 20130101 |
International
Class: |
E21D 23/00 20060101
E21D023/00; E21D 23/10 20060101 E21D023/10; E21D 23/04 20060101
E21D023/04 |
Claims
1. A mining system comprises: a continuous miner; a movable roof
support; a roof bolter; and a flexible conveyor train positioned
with its front end located under the roof support and extending
underneath the roof bolter.
2. The system of claim 1, wherein the roof support comprises: two
tracks; legs mounted on the two tracks; and a canopy supported by
legs and the two tracks; wherein the legs and the tracks are spaced
apart to define a gap that is wide enough to receive the flexible
conveyor train through the gap.
3. The system of claim 2, wherein the gap is at least 14 feet (4.3
meters).
4. The system of claim 2, wherein the legs comprise hydraulic
pistons.
5. The system of claim 2, wherein the moveable roof support is a
first roof support and the mining system comprises a second
moveable roof support.
6. The system of claim 5, comprising chains extending between a
canopy of the first moveable roof support and a canopy of the
second moveable roof support
7. The system of claim 2, wherein the moveable roof support
comprises a canopy and an extendable portion movable between an
extended position and a retracted position by a piston.
8. The system of claim 1, wherein the roof bolter comprises: two
tracks; a canopy supported by the two tracks; wherein the tracks
are spaced apart to define a gap that is wide enough to receive the
flexible conveyor train through the gap.
9. The system of claim 8, wherein the gap is at least 14 feet (4.3
meters).
10. The system of claim 8, wherein the roof bolter comprises six
drill masts.
11. The system of claim 8, wherein the canopy is supported by legs
mounted on the two tracks.
12. The system of claim 11, wherein the legs comprise hydraulic
pistons.
13. The system of claim 8, wherein the canopy is supported by a
scissors lift system mounted on the two tracks.
14. The system of claim 8, wherein the canopy comprises a work
platform.
15. The system of claim 14, wherein the roof support comprises four
drill masts pivotably mounted to the working platform and oriented
upwards to install roof bolts.
16. The system of claim 15, wherein the roof support comprises two
drill masts that are pivotably mounted to the working platform and
oriented sideways to install rib bolts.
17. A method of mining comprising: positioning a first movable roof
support between a continuous miner and a roof bolter; and extending
a flexible conveyor train between tracks of the roof bolter and
between tracks of the first movable roof support and positioning a
hopper of the flexible conveyor train to receive output of the
continuous miner.
Description
CLAIM OF PRIORITY
[0001] This application claims priority under 35 USC .sctn. 119(e)
to U.S. Patent Application Ser. No. 62/444,298, filed on Jan. 9,
2017 and 62/511,229, filed on May 25, 2017, the entire contents of
each application is hereby incorporated by reference.
TECHNICAL FIELD
[0002] This invention relates to mining underground formations, and
more particularly to systems and methods for mining underground
formations.
BACKGROUND
[0003] Continuous miners are typically machines with a large
rotating steel drum equipped with tungsten carbide picks that rip
material (e.g., coal) from an underground formation (e.g., a coal
seam). Continuous miners account for about 45 percent of
underground coal production. Conveyors transport the removed coal
from the seam. Remote-controlled continuous miners are used to work
in a variety of difficult seams and conditions, and robotic
versions controlled by computers are becoming increasingly common.
Continuous mining is a misnomer, as room and pillar coal mining is
very cyclical. In the US, one can generally cut .about.20-35 feet
(.about.6-12 meters) before the continuous miner backs out and the
roof is supported by a roof bolter, after which, the face has to be
serviced, before it can be advanced again. During servicing, the
"continuous" miner moves to another face. Some continuous miners
can bolt the face while cutting coal. Most continuous mining
machines in use in the US lack the ability to bolt. This may partly
be because incorporation of bolting makes the machines wider, and
therefore, less maneuverable.
[0004] A roof bolter is a rubber tired or cat-driven machine used
to install rock bolts in mines, tunnels, underground power plants,
and storage facilities. Roof bolting is also a common application
in underground coal mines for securing mine roofs to be
self-supportive. It is extremely dangerous as an occupation,
accounting for nearly 56 percent of injuries in underground coal
mining operations.
SUMMARY
[0005] Methods and equipment have been developed that can provide
increased production relative to conventional continuous
miner/bolter methods and systems. In addition, these methods and
systems can also increase the safety of equipment operators
relative to conventional miner/bolter methods and systems. These
methods and equipment can combine the use of canopies, roof
bolters, continuous miners, and flexible conveyor trains.
[0006] In one aspect, mining systems include: a continuous miner; a
movable roof support; a roof bolter; and a flexible conveyor train
positioned with its front end located under the roof support and
extending underneath the roof bolter. Embodiments of mining systems
can include one or more of the following features.
[0007] In some embodiments, the roof support includes: two tracks;
legs mounted on the two tracks; and a canopy supported by legs and
the two tracks; wherein the legs and the tracks are spaced apart to
define a gap that is wide enough to receive the flexible conveyor
train through the gap. In some cases, the gap is at least 14 feet
(4.3 meters). In some cases, the legs comprise hydraulic pistons.
In some cases, the moveable roof support is a first roof support
and the mining system includes a second moveable roof support. The
system can include chains extending between a canopy of the first
moveable roof support and a canopy of the second moveable roof
support. In some cases, the moveable roof support comprises a
canopy and an extendable portion movable between an extended
position and a retracted position by a piston.
[0008] In some embodiments, the roof bolter includes: two tracks; a
canopy supported by the two tracks; wherein the tracks are spaced
apart to define a gap that is wide enough to receive the flexible
conveyor train through the gap. In some cases, the gap is at least
14 feet (4.3 meters). In some cases, the roof bolter comprises six
drill masts. In some cases, the canopy is supported by legs mounted
on the two tracks. In some cases, the legs comprise hydraulic
pistons. In some cases, the canopy is supported by a scissors lift
system mounted on the two tracks. In some cases, the canopy
comprises a work platform. In some cases, the roof support
comprises four drill masts pivotably mounted to the working
platform and oriented upwards to install roof bolts. In some cases,
the roof support comprises two drill masts that are pivotably
mounted to the working platform and oriented sideways to install
rib bolts.
[0009] In some aspects, methods of mining include: positioning a
first movable roof support between a continuous miner and a roof
bolter; and extending a flexible conveyor train between tracks of
the roof bolter and between tracks of the first movable roof
support and positioning a hopper of the flexible conveyor train to
receive output of the continuous miner.
[0010] In operation, these systems and methods facilitate mining a
deeper cut than conventional systems while providing roof and rib
protection to the operators
[0011] The details of one or more embodiments of the disclosure are
set forth in the accompanying drawings and the description below.
Other aspects, features, and advantages of the disclosure will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0012] FIGS. 1A and 1B are, respectively, a plan view and a profile
view of a mining system.
[0013] FIGS. 2A and 2B are, respectively, a plan view and a profile
view of a mining system.
[0014] FIGS. 3A and 3B are, respectively, a plan view and a profile
view of a roof support.
[0015] FIGS. 4A and 4B are, respectively, a plan view and a profile
view of paired roof supports.
[0016] FIGS. 5A, 5B, and 5C are, respectively, a plan view, a
profile view (separated), and a profile view (together) of paired
roof supports.
[0017] FIGS. 6A and 6B are, respectively, a plan view and a profile
view of a roof bolter.
[0018] FIG. 7 is an end view of a roof bolter.
[0019] FIGS. 8A and 8B are perspective views of a continuous
miner.
[0020] FIG. 9 is a perspective view of a flexible conveyor
train.
[0021] FIG. 10 is a cut sequence for an advancing mining
sequence.
[0022] FIGS. 10A-10I are plan views of an advancing mining
sequence.
[0023] FIG. 11 is a cut sequence for a retreating mining
sequence.
[0024] FIGS. 11A-11G are plan views of a retreating mining
sequence.
[0025] FIG. 12 is a cut sequence for a retreating mining
sequence.
[0026] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0027] Methods and equipment have been developed that can provide
increased production relative to conventional miner/bolter methods
and systems. In addition, these methods and systems can also
increase the safety of equipment operators relative to conventional
miner/bolter methods and systems. These methods and equipment can
combine the use of roof supports, roof bolters, continuous miners,
and flexible conveyor trains. We discuss examples of these methods
and equipment in the context of extracting coal from a coal bed but
they can be applied to other mining applications including, for
example, mining trona, gypsum, potash and salt.
[0028] FIGS. 1A and 1B illustrate a mining system 100 that can be
deployed, for example, off a surface mine highwall or from
previously developed underground workings. The mining system 100
includes a continuous miner 110, two roof supports 112, and a roof
bolter 114. A flexible conveyor train 116 is positioned with its
front end 118 located under the canopy of the roof support 112 and
extends underneath the roof bolter 114. The roof support 112 and
the roof bolter 114 both have split bases (e.g., tracks and
hydraulic jacks that straddle the flexible conveyor train 116.
[0029] FIGS. 2A and 2B illustrate a mining system 100' that is
substantially similar to the mining system 100 but only includes
one roof supports 112. Both the mining system 100 and the mining
system 100' can provide increased production and safety relative to
conventional miner/bolter methods and systems but the mining system
100 is anticipated to provide more operational flexibility than the
mining system 100'.
[0030] In operation, these systems and methods facilitate mining a
deeper cut than conventional systems while providing roof and rib
protection to the operators. The independent operation of the
continuous miner 110, the roof support(s) 112, and the roof bolter
114 balances out the inherent imbalance between the cutting/loading
cycle and the roof support cycle. To achieve mining without
stopping for roof bolting, it is necessary to install four roof
bolts in approximately the time it takes to mine ahead 4 feet (1.2
meters) with the continuous miner. Mining ahead 4 feet (1.2 meters)
is about two sump cycles (e.g., sump, rip/load, set over, sump,
rip/load then clean up each side) of the continuous miner 110. It
is anticipated that operators of the roof bolter 114 can install
four roof bolts in approximately the same time as required for a
cutting/loading/cleanup/set over cycle of the continuous miner 110.
In the event that operators are not able to install four bolts,
move up the roof bolter 114 and the roof support 112 in the same
amount of time as the sump cycle, the roof support 112 provides the
"lost motion" time. By driving straight ahead, these systems and
methods provide long (e.g., hundreds of feet) uninterrupted runs
for the mining and give the option to retreat by shortwall,
longwall or slabbing/pillar recovery from a surface mine highwall
or previously developed deep mine entries.
[0031] FIGS. 3A and 3B illustrate the roof support 112 in more
detail. The roof support 112 includes a canopy 120 that is
supported by four legs 122 (e.g., hydraulic jacks) mounted on two
tracks 124. The legs 122 and the tracks 124 are spaced apart to
define a gap 126 that is wide enough to receive the flexible
conveyor train 116 and/or the continuous miner between the legs 122
and the tracks 124. Similarly, the roof supports 112 have a height
measured to the underside of the canopy of .about.6.5 feet
(.about.2 meters) during mining operations.
[0032] For example, the roof support 112 has tracks 124 that are 2
feet (0.6 meters) wide and spaced 14.5 feet (4.4 meters) apart.
This configuration provides a gap between the tracks 124 that is
wide enough to receive standard continuous miners which are 11.5
feet (3.5 meters) wide with a clearance of 1.5 feet (0.5 meters) on
either side of the continuous miner. The feeder/breaker and the
body of the flexible conveyor train 116 are typically .about.7 feet
(.about.2.1 meters) wide and 5 feet (1.5 meters) wide,
respectively, and easily pass between the tracks 124 of the roof
support 112. The flexible conveyor train 116 typically has a height
of approximately 5 feet (1.5 meters) and the continuous miner 110
typically has a height of .about.6 feet (.about.1.8 meters). This
configuration enables the roof support 112 to straddle both the
continuous miner 110 and the flexible conveyor train 116 and pass
over the continuous miner 110. Some mining systems 100 use roof
supports 112 that have legs and tracks that are spaced far enough
apart (e.g., 7.5 feet (2.3 meters), 8 feet (2.4 meters), 8.5 feet
(2.6 meters)) to straddle the flexible conveyor train 116 but not
the continuous miner 110.
[0033] Some systems are configured to use rubber tired mined
material haulage equipment rather than a flexible conveyor train to
transport mined material away from the continuous miner 110. In
these systems, the roof support 112 may be wider to accommodate the
rubber tired mined material haulage equipment. Some systems use
roof supports and/or roof bolters that are mounted on rubber tires
rather than tracks.
[0034] Under permanently supported roof (e.g., bolted roof), the
roof supports 112 can be used as a canopy rather than being
pressurized against roof. This provides additional protection for
miners while avoiding damage to the permanent roof support. In
unsupported sections, the roof supports 112 can be pressurized
against roof.
[0035] The legs 122 (e.g., hydraulic jacks) of the roof support 112
hydraulically telescope to raise the canopy into contact with the
roof of the mine. Some roof supports 112 are configured to provide
a false roof effect without being raised into contact with the roof
of the mine. The canopy 120 of the roof support 112 provides
protection from falling roof and rib material, enables a much
deeper cut, and reduces the need to change from one entry to
another.
[0036] Some roof supports 112 incorporate a motor operable to drive
the tracks 124. Some roof supports 112 include rib protection such
as, for example, heavy chains hanging down from the side edges of
the canopy.
[0037] Using a pair of roof supports 112 with one roof support 112
moving with the continuous miner 110 and one roof support 112
moving with the roof bolter 114 further decouples the advance of
the continuous miner 110 from the advance of the roof bolter 114 to
increase operational flexibility and speed of mining. Some roof
supports include features configured to provide roof protection in
gaps that can develop between the main canopies of the roof
supports due to the different speeds of advance of the continuous
miner and the roof bolter.
[0038] FIGS. 4A and 4B show a pair of roof supports 113. Each roof
support 113 is substantially similar to the roof support 112 but
includes a canopy 120 with an extendable portion 121 and a
hydraulic piston 123. If a gap starts to develop between the main
canopies of the roof support 113 moving with the continuous miner
110 and the roof support 113 moving with the roof bolter 114, the
hydraulic piston 123 extends to deploy the extendable portion 121
of one or both roof supports 113.
[0039] FIGS. 5A-5C show a pair of roof supports 115. Each roof
support 115 is substantially similar to the roof support 112. The
pair of roof supports 115 are joined by chains 117 that extend
between the canopies of the roof supports. The chains 117 provide
protection if a gap starts to develop between the main canopies of
the roof support 115 moving with the continuous miner 110 and the
roof support 115 moving with the roof bolter 114 (see FIGS. 5A and
5B). When a gap starts to develop between the main canopies of the
roof supports 115, the chains 117 stretch between the canopies 120
of the roof supports 115. Unlike the roof supports 113, the roof
supports 115 are physically linked. The linkage between roof
supports 115 may provide better roof protection at a cost of
reduced operational flexibility relative to the roof supports
113.
[0040] FIGS. 6A and 6B illustrate the roof bolter 114 in more
detail. The roof bolter 114 includes a working platform 128. Like
the canopy 120 of the roof support, the working platform 128 is
supported by four legs 122 mounted on two tracks 124. The legs 122
and the tracks 124 are spaced apart to define a gap 126 that is
wide enough to receive the flexible conveyor train 116 and/or the
continuous miner between the legs 122 and the tracks 124. This
configuration enables the roof bolter 114 to straddle both the
continuous miner 110 and the flexible conveyor train 116 and pass
over the continuous miner 110. Some systems are configured to use
rubber tired mined material haulage equipment such as, for example,
shuttle cars or ram cars, rather than a flexible conveyor train to
transport mined material away from the continuous miner 110. In
these systems, the roof bolter 114 may be wider (e.g., define a gap
of 11.5 feet (3.5 meters), 12 feet (3.7 meters), 13 feet (4
meters), or more) to accommodate the rubber tired mined material
haulage equipment. The legs 122 of the roof bolter 114
hydraulically telescope to raise the working platform into position
for roof bolts to be installed into the roof of the mine. Depending
on the entry height, the operators of the roof bolter 114 can be on
top of or underneath the working platform 128. The canopy 120 of
the roof support 112 provides protection in front of the roof
bolter 114.
[0041] The work platform 128 also functions as a canopy for workers
under the work platform. Some roof bolters include a frame that is
more robust than a normal portal type canopy. The drill masts 132
are hung from the canopy of the working platform 128. The roof
bolter 114 includes four drill masts 132 that are pivotably mounted
to the working platform and generally oriented upwards to install
roof bolts. The roof bolter 114 includes two drill masts 132 (one
on each side) that are pivotably mounted to the working platform
and generally oriented sideways to install rib bolts.
[0042] Operators can move across the front of the work platform 128
when performing roof bolting. Three operators are anticipated to
operate the roof bolter 114--one operator installing bolts with the
left two roof drill masts and the left rib drill mast, one operator
installing bolts with the right two roof drill masts and the right
rib drill mast, and a helper. This manning combined with the
configuration of the roof bolter 114 is anticipated to enable
mining sequence described in this disclosure.
[0043] Using a follow-on roof bolter in this fashion enables
bolting to occur quicker than a place change system in which a
continuous miner is withdrawn from a face and replaced by a roof
bolter while affording additional protection for the operators of
the roof bolter 114. The roof support 112 provides temporary roof
support for the operators of the roof bolter 114. By delinking the
roof bolter function from the mining and conveying functions
provides for increased production over systems in which roof
bolters are mounted on continuous miners.
[0044] Some roof bolters include an electric motor to move the roof
bolter, hydraulic pumps to raise and lower the work platform,
blowers and a dust box. A prepackaged box 130 holds roof bolting
supplies. It is anticipated that the working platform 128 will hold
two or more shifts worth of roof bolting supplies in the
prepackaged box 130. As illustrated, the prepackaged box 130 sits
on top of the work platform 128 of the roof bolter 114. This
configuration is typically used when the mining height is 10-18
feet (3-5.5 meters). When the mining height is less than 10 feet (3
meters), the prepackaged box 130 is typically slung underneath the
work platform 128 of the roof bolter 114. The ability of the roof
bolter 114 to tram over the flexible conveyor train 116 facilitates
resupply. To resupply, the roof bolter 114 trams back to a crosscut
where, for example, a diesel forklift removes the depleted supply
box and loads a fresh prepackaged supply box from the crosscut.
Such resupply is typically done during power and belt moves to
limit impacts on mining operations.
[0045] FIG. 7 illustrates a roof bolter 144 that is generally
similar to the roof bolter 114. However, the roof bolter 144
includes a scissors lift system 146 rather than the hydraulic jacks
of roof bolter 114. The work platform 128 of the roof bolters is
not required to support the roof so hydraulic jacks are not
required.
[0046] FIGS. 8A and 8B illustrate the continuous miner 110 in more
detail. The continuous miner 110 has a large rotating steel drum
134 equipped with tungsten carbide teeth 136 that rip coal from the
coal face. Continuous miners are traditionally used in a "room and
pillar" mining system where the mine is divided into a series of
18-to-20 foot (5.5-to-6.1 meter) "rooms" or work areas cut into the
coal bed. A continuous miner can mine as much as 38 short tons of
coal a minute, and can remove swaths of material approximately 11.5
feet (3.5 meters) wide. Continuous miners can utilize, for example,
conveyors, ram cars or shuttle cars to transport the removed coal
from the coal face, and unlike the shearers often used in longwall
mining operations, is independently mobile rather than carried or
otherwise conveyed along the length of the coal face.
[0047] A trailing cable 138 (see FIG. 8B) provides power to the
continuous miner 110. The cable can be carried and deployed from
the flexible conveyor train 116. The operator controls the
continuous miner by wireless systems. The water is supplied to the
continuous miner through a separate water hose, which can also be
mounted on the flexible conveyor train 116.
[0048] FIG. 9 illustrates the flexible conveyor train 116 in more
detail. The material extracted by the continuous miner 110 is
loaded into a hopper 140 located at the front end of the flexible
conveyor train 116. The flexible conveyor train removes the
received material from the face by conveying it via a conveyor belt
142 running along the length of the flexible conveyor train 116.
Receiving the coal from the continuous miner 110 and transports the
coal, for example, to a fixed section belt for removal from the
mine, the flexible conveyor train 116 reduces the total number of
mobile machines (e.g., shuttle cars) and workers in the mine.
Higher capacity production is also possible as the continuous
haulage eliminates the bottle necks and wait times during batch
haulage systems. In addition, material degradation is reduced with
the reduction of transfer points improving product quality while
reducing dust and improving safety. Flexible conveyor trains are
typically provided with radio remote controls similar to the
continuous miners.
[0049] In operation, the systems and methods described above
facilitate mining a deeper cut than conventional systems while
providing roof and rib protection to the operators. The independent
operation of the roof support 112 and the roof bolter 114 balances
out the inherent imbalance between the cutting/loading cycle and
the roof support cycle. To achieve mining without stopping for roof
bolting, it is necessary to install four roof bolts in
approximately the time it takes to mine ahead 4 feet (1.2 meters)
with the continuous miner. Mining ahead 4 feet (1.2 meters) is
about two sump cycles (e.g., sump, rip/load, set over, sump,
rip/load then clean up each side) of the continuous miner 110. It
is anticipated that operators of the roof bolter 114 can install
four roof bolts and two rib bolts in approximately the same time as
required for a cutting/loading/cleanup/set over cycle of the
continuous miner 110. In the event that operators are not able to
install the bolts, move up the roof bolter 114 and the roof support
112 in the same amount of time as the sump cycle, the roof support
112 provides the "lost motion" time. By driving straight ahead
like, these systems and methods provide long (e.g., thousands of
feet) uninterrupted runs for the mining and give the option to
retreat by shortwall, longwall or slabbing/pillar recovery from a
surface mine highwall or previously developed deep mine
entries.
[0050] FIG. 10 shows a cut sequence for using an embodiment of the
mining system 100 to develop a mine 200. The mine 200 includes a
No. 1 entry (left entry) 150, a No. 2 entry (center entry) 152, and
a No. 3 entry (right entry) 154. FIGS. 10A-10I illustrate
implementation of this embodiment of the mining system 100.
Although the mine 200 has a three-entry system, other mines may
have different numbers of entries depending on factors including,
for example, the flexible conveyor train limitations and
ventilation requirements.
[0051] In FIG. 10, faces 157 of the entries are indicated by dashed
lines. The cuts are indicated by numbered arrows in the entries and
crosscuts. As shown in FIG. 10A, the continuous miner 110, the roof
support 112, the roof bolter 114, and the flexible conveyor train
116 are initially located in the middle entry 152 outby the
crosscut to be mined next. When mined, this crosscut is part of Cut
#1 (FIG. 10).
[0052] An independent mobile roof bolter 148 is located in the left
entry 150 and another independent roof bolter 148 is located in the
right entry 154. Each of the entries has a width W1 of .about.18
feet (.about.5.5 meters) and the entries are separated from each
other by a width W2 of .about.65 feet (.about.20 meters) of the
formation being mined. The mobile roof bolters 148 are used to
install roof bolts 156 in the ends of the left entry 150 and the
right entry 154. These roof bolts 156 are not shown in FIGS.
10B-10I to make it easier to see other system components.
[0053] Cut #1 (FIG. 10) is mined and bolted to the left until it
cuts through the bolted left entry 150. The roof supports 112 and
the roof bolter 114 follow the continuous miner 110 with the roof
supports 112 and the roof bolter 114 straddling the flexible
conveyor train 116 (FIG. 10B). The crosscut is .about.75 feet
(.about.23 meters) long and the crosscut and No. 2 entry define an
angle .lamda. of .about.60-75 degrees.
[0054] The continuous miner 110, the roof support 112, and the roof
bolter 114 are operated in the cutting/loading cycle and the roof
support cycle described above during the advance. The roof supports
112 function as a canopy (i.e., they are not pressurized against
the roof while under the bolted entry). The roof supports 112 are
only pressurized as they advance under the unbolted roof. The roof
bolter 114 follows along bolting the unsupported roof as it becomes
mined.
[0055] The second roof support 112 functions as the temporary roof
support for the bolting function. In some systems, the roof bolter
114 also includes integrated temporary roof support components.
This approach frees up the second roof support 112 to continue on
with the other roof support 112 and the continuous miner 110.
[0056] Cut #1 (FIG. 10) is continued to extend the No. 1 entry. The
continuous miner 110, the roof supports 112, and the roof bolter
114 continue to mine and bolt up the left entry 150 for a distance
that places the face 20 feet (.about.6 meters) past the next
crosscut to be developed (i.e., when Cut #4 is made). In this
illustrated layout, this continuation of Cut #1 extends the
left-hand entry .about.100 feet (.about.30 meters) from the initial
crosscut.
[0057] After Cut #1 is completed, the continuous miner 110, the
roof supports 112, the roof bolter 114, and the flexible conveyor
train 116 are then retreated back to the middle entry 152. When the
advance is stopped, the roof bolter 114 is separated from the end
of the entry by the roof supports 112 and the continuous miner 110.
The conventional roof bolter 148 bolts the last 50-55 feet
(.about.15-17 meters) of the No. 1 entry left unbolted due to this
separation after the continuous miner 110, the roof support 112,
the roof bolter 114, and the flexible conveyor train 116 retreat
back to the middle entry 152.
[0058] Cut #2 (FIG. 10) is mined and bolted to the left until it
cuts through the bolted right-hand entry and extends the right-hand
entry in the same manner that the Cut #1 was mined and bolted (FIG.
10C). After Cut #2 is completed, the continuous miner 110, the roof
supports 112, the roof bolter 114, and the flexible conveyor train
116 are then retreated back to the middle entry 152.
[0059] Cut #3 (FIG. 10) is mined and bolted to extend the middle
entry 152. The continuous miner 110, the roof supports 112, and the
roof bolter 114 mine and bolt the middle entry 152 past where the
next crosscuts will be turned (FIG. 10D). The middle entry is mined
and bolted at least 10 feet (.about.3 meters) past where the next
crosscuts are to be turned left in Cut #4 and right in Cut #5. This
leaves 30-35 feet (.about.9-11 meters) of unsupported roof inby the
crosscuts that will be bolted by the conventional roof bolter (148)
as soon as practicable during the mining of Cut 4 or Cut 5.
[0060] The independent mobile roof bolter 148 from the left entry
150 can be used to bolt the unsupported roof at the end of the
middle entry 152. The continuous miner 110, the roof support 112,
the roof bolter 114, and the flexible conveyor train 116 start the
crosscut to the right entry 154. In some cut sequences, the order
of forming the crosscuts is reversed and the independent mobile
roof bolter 148 from the right entry 154 is used to bolt the
unsupported roof at the end of the middle entry 152.
[0061] FIG. 10F-10H illustrate one approach to using independent
mobile roof bolter 148 from the left entry 150 to bolt the
unsupported roof at the end of the middle entry 152. When the
crosscut is long enough to receive the continuous miner 110, the
roof support 112, and the roof bolter 114, the flexible conveyor
train 116 retreats into the middle entry 152 outby the intersection
of the crosscuts and the middle entry 152. The independent mobile
roof bolter 148 from the left entry 150 moves though the cleared
intersection of the crosscuts and the middle entry 152. After the
independent mobile roof bolter 148 enters the No. 2 entry inby the
intersection, the flexible conveyor train 116 and the roof bolter
114 advance into the crosscut to rejoin the continuous miner 110
and the roof support 112. The continuous miner 110, the roof
support 112, the roof bolter 114, and the flexible conveyor train
116 finish the crosscut and extend the right entry 154 while the
independent mobile roof bolter 148 bolts the unsupported roof at
the end of the middle entry 152.
[0062] As shown in FIGS. 10H and 10I, the continuous miner 110, the
roof support 112, the roof bolter 114, and the flexible conveyor
train 116 retreat into the middle entry 152 outby the intersection
after extending the right entry 154. After the continuous miner 110
clears the right entry 154, the independent mobile roof bolter 148
moves up and bolts the unsupported roof at the end of the right
entry 154. After the continuous miner 110 clears the intersection
between the crosscuts and the middle entry 152, the other
independent mobile roof bolter 148 moves back to the left entry
150. That independent mobile roof bolter 148 bolts the unsupported
roof at the end of the left entry 150 while the continuous miner
110, the roof support 112, the roof bolter 114, and the flexible
conveyor train 116 repeat the steps of extending the No. 2 entry
and forming the next crosscut.
[0063] Cut #4, Cut #5, and Cut #6 (FIG. 10) are mined and bolted
similar manner as Cut #1, Cut #2, and Cut #3 (FIGS. 10E-10F). As
shown in FIG. 10E, when repeating the sequence of forming a
crosscut and extending the No. 1 entry in Cut #4, completion of the
crosscut isolates a trapezoidal pillar in the formation that is
.about.100 feet (.about.30 meters) long and .about.65 feet
(.about.20 meters) wide. The iteration of the cut sequences can be
continued to extend the entries into the formation being mined
(see, for example, Cut #7, Cut #8, and Cut #9 in FIG. 10).
[0064] FIGS. 10A-10I illustrate an embodiment of the mining system
100 that includes two roof supports 112 between the continuous
miner 110 and the roof bolter 114. Single roof supports such as,
for example, those shown in FIGS. 2A and 2B could also be used. The
paired roof supports provide operational flexibility but can result
in additional roof unsupported at the end of the entries when the
mining system retreats away from a face.
[0065] FIG. 11 shows a cut sequence for using an embodiment of the
mining system 100 to mine the panel developed in the sequence
illustrated in FIGS. 10A-10I. FIGS. 11A-11G illustrate mining the
panel developed in the sequence illustrated in FIGS. 10A-10I. The
continuous miner 110 and the flexible conveyor train are used in
this retreat mining sequence. The illustrated sequence uses two
roof supports 112 to extend the length of cuts off the entries
while maintaining overhead protection without requiring additional
roof bolting. The roof bolter 114 used in the advance is removed
before beginning the retreat sequence.
[0066] FIG. 11A shows a three-entry system with the continuous
miner 110 and two roof supports 112 deployed in the left entry 150.
The flexible conveyor train 116 extends from the middle entry 152,
through a crosscut, and up the left entry 150 through the two roof
supports 112 to the continuous miner 110. Pairs of mobile roof
supports 149 deployed in each of the entries 150, 152, 154. The
middle entry 152 extends to a bleed air shaft 190.
[0067] FIG. 11B shows the initial cuts (Cut #1-Cut #5 in FIG. 11)
being made by the continuous miner 110. The first cut is to the top
left. Terms of orientation are used to indicate position relative
to the figures being described rather than absolute orientation.
The protection of the two roof supports 149 allow the continuous
miner to advance .about.50-60 feet (15.2-18.3 meters) before
retreating into the left entry 150 in preparation for the next cut.
Cuts to the right are made to intersect the crosscut between the
middle entry 152 and the left entry 150. Cuts to the left and right
alternate with the two mobile roof supports following along the No.
1 entry 150 as the retreat sequence continues.
[0068] FIG. 11C shows the cuts to the left continuing but the cuts
to the right changing orientation. On the first cut to the right
(Cut #6 in FIG. 11), the distance between the No. 1 entry 150 and
the crosscut approximately matches the length of the continuous
miner 110 and the two roof supports 112. The second right-side cut
(Cut #10 in FIG. 11) runs along the No. 1 entry and reduces the
distance between the mined area and the No. 2 entry. The two mobile
roof supports continue to follow along the No. 1 entry 150 as the
retreat sequence continues.
[0069] FIGS. 11D and 11E show a similar sequence of cuts being made
off the right entry 154.
[0070] FIG. 11F shows cuts from the middle entry 152 being used to
mine the pillars with alternating right- and left-side cuts (Cut
#21-Cut #28 in FIG. 11). The cuts made along the left entry 150
(see FIG. 11C) and the No. 3 entry (see FIG. 11E) reduce the width
of the pillars to allow the alternating right- and left-side cuts
from the middle entry 152 to be performed without additional roof
protection beyond the roof supports 112 and the mobile roof
supports 149. This approach is anticipated to provide higher
production rates than systems that need roof bolting during the
retreat sequence. Like the development sequence, the retreat
sequence is also anticipated to provide higher productions rates
than approaches that include higher numbers of equipment moves.
[0071] FIG. 11G shows the continuous miner 110 and the roof
supports 112 before they pull back down the No. 2 entry 152 in
preparation for repeating the process illustrated in FIGS. 11A-11H.
The remaining portions of the pillars by the mobile roof supports
149 in the middle entry 152 will often be left in place.
[0072] A number of embodiments of mining systems and methods have
been described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. For example, FIG. 12 shows the cuts for
another retreat mining sequence. This approach leaves additional
portions or the formation in place to provide additional support
near intersections where roof stresses will be greatest.
Accordingly, other embodiments are within the scope of the
following claims.
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