Mining or in situ disintegration of hard material – Processes – Mine safety
Utility Patent
1998-03-10
2001-01-02
Lillis, Eileen D. (Department: 3673)
Mining or in situ disintegration of hard material
Processes
Mine safety
Utility Patent
active
06168240
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to atmospheric detection in an underground mine and, more particularly, measuring the presence of methane gas near a mine face during continuous mining operations.
2. Description of the Prior Art
Coal is typically found in substantial horizontal seams extending through rock strata, such as limestone, sandstone or shale. Surface mining and underground mining are the primary methods used to mine coal. Surface mining may be strip mining which involves the removal of the overburden by means of a dragline or other earth moving equipment to fully expose the coal seam for recovery. However, strip mining is limited by the depth of the overburden which eventually makes strip mining impractical. When the depth of the overburden makes strip mining impractical, a large quantity of coal may remain in the seam. Recovery of this coal is accomplished by highwall mining, wherein an entry or a hole is initiated at the exposed face of the seam at the highwall, and mining follows the seam inwardly from the highwall forming a bore. One particularly successful and innovative apparatus for continuously mining coal by highwall mining is the ARCHVEYOR® continuous mining apparatus as described in U.S. Pat. No. 5,667,279, which is hereby incorporated by reference.
The ARCHVEYOR® continuous mining apparatus includes a continuous miner, a tramming conveyor and a load-out vehicle. A bolter car may be positioned between the continuous miner and the tramming conveyor. The miner mines coal at a mine face. The mined coal is conveyed to the tramming conveyor and deposited onto a transverse conveyor. The transverse conveyor then deposits the mined coal into hopper cars or trucks for transport. An operator located in the load-out vehicle controls the operation of the continuous miner and the tramming conveyor.
A constant concern in any underground mining operation is the buildup of methane gas. Where human miners are involved, continuous monitoring of methane, as well as oxygen and carbon monoxide, is monitored to ensure safe operating conditions. Mine Safety Health Administration of the United States Department of Labor (MSHA) sets forth the rules and regulations for monitoring the methane gas levels in mines. In the case of highwall mining, MSHA does not require monitoring of the methane gas levels at the mine face using the ARCHVEYOR® continuous mining apparatus because all people involved in the mining operation are positioned outside the underground bore formed by the continuous miner. In other words, the load-out vehicle and the operator are located outside the underground bore.
However, in other applications of continuous mining, such as wing mining where humans are positioned underground, constant monitoring must be conducted near the mine face. The ARCHVEYOR® continuous mining apparatus can be used in this application. On a typical miner section, a bolter car may also be provided for installing mine roof bolts and support plates behind the continuous miner. Typically, the bolter car is positioned approximately forty feet behind the continuous miner. The bolter car installs the mine roof bolts and the bearing plates in the mine roof approximately forty feet behind the mine face. Hence, the mine shaft formed by the continuous miner has a supported roof at a distance beyond forty feet of the mine face and an unsupported roof at a distance less than forty feet toward the mine face.
Until recently, MSHA permitted methane gas levels to be measured at the last row of permanent support in the face area of the mine during continuous mining applications as shown in FIG.
1
. Specifically,
FIG. 1
shows a mine shaft
10
defined by two spaced apart ribs or walls
12
(only one of which is shown), a mine roof
14
, a mine floor
16
and a mine face
18
. The mine roof
14
has a supported portion
20
beyond a distance X measured from the mine face
18
and an unsupported portion
22
the distance X as measured toward the mine face
18
. Under the previous MSHA rules, a miner
24
would monitor the gas levels of the mine shaft
10
at the distance X using a hand-held gas detector
26
. Typically, under the MSHA rules, continuous mining stopped and then the miner
24
took gas readings using the detector
26
every twenty minutes. If the methane gas reading was unacceptable (too high), then mining was stopped until the methane gas level was reduced. As should be evident, this procedure puts the miner
24
at risk and adds to the cost of extracting coal since the continuous miner must be stopped every twenty minutes. Some continuous miners include a methane sensor coupled to a display attached to the continuous miner in series. If the methane sensor measures a level above a certain level, say 2%, then all power to the sensor and the continuous miner is cut off. During the period of time between shutdown and reactivation, which requires a miner
24
to enter the mine shaft
10
to restart the continuous miner, the sensor cannot measure methane levels. This arrangement places the miner
24
at great risk since gas levels are not known. Further, even during extended cut operations, the monitor cannot be read since it is positioned under the unsupported portion
22
.
Recently, MSHA changed the rules for measuring gas levels in mining. Specifically, pursuant to 30 C.F.R. §§ 75.323(b)(1) and (2) and 75.362(d)(1), MSHA now requires that methane gas readings be taken in close proximity of the mine face
18
. However, under MSHA rules, the miner
24
can be no closer to the mine face
18
than under the old MSHA rules due to the unsupported roof conditions. To comply with these new MSHA rules, the detectors
26
have been fitted with probe extensions
28
, shown in phantom in FIG.
1
. The probe extensions
28
have a length X of approximately forty feet so that gas readings can be taken at the mine face
18
. This arrangement is extremely cumbersome and time consuming to use. Further, this method for measuring methane gas near the mine face
18
yields inaccurate results since it has been found that methane gas levels decrease when the mine face is not being worked by the continuous miner.
Therefore, it is an object of the present invention to safely measure gas levels near a mine face without interrupting mining by a continuous miner.
SUMMARY OF THE INVENTION
The present invention is an atmospheric detection system for use in a mine that includes a continuous miner, a sensor adapted to detect an atmospheric condition, a controller and a display. The continuous miner includes a rotary cutter head attached to a frame and a motor for driving the rotary cutter head. The sensor is mounted to the continuous miner. A first power line is provided for supplying the power to the motor. The controller is coupled to the motor and the first power line for controlling rotation of the rotary cutter head at a remote location. A second power line is provided for supplying power to the sensor. The monitor is coupled to the sensor for detecting the atmospheric condition at a location remote of the sensor. The sensor is positioned in close proximity to the rotary cutter head. Preferably, the rotary cutter head is rotatably coupled to a boom that is pivotally mounted to the frame. The sensor can be mounted to the boom.
The continuous miner can include a miner conveyor in fluid communication with the rotary cutter head and an arrangement for moving along a mine floor. A tramming conveyor can be coupled to the continuous miner. The tramming conveyor includes a conveyor in fluid communication with the miner conveyor. The tramming conveyor is also operatively coupled to the controller for controlling movement of the tramming conveyor along a mine floor and movement of the tramming conveyor. An operator station can be provided where the controller and the display are positioned therein. Preferably, the sensor is a methane sensor. The methane sensor can continuously or intermittently detect methane levels. Additional sensors can be provided, such as an air
Retzer Patrick E.
Stickel Danny L.
Archveyor Pty Ltd.
Lillis Eileen D.
Senniger Powers Leavitt & Roedel
Singh Sunil
LandOfFree
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