Mining or in situ disintegration of hard material – Processes – With material-handling
Reexamination Certificate
2000-12-18
2002-10-08
Shackelford, Heather (Department: 3673)
Mining or in situ disintegration of hard material
Processes
With material-handling
C299S019000
Reexamination Certificate
active
06460937
ABSTRACT:
TECHNICAL FIELD
The present invention relates to mining, in particularly longwall mining,
BACKGROUND OF THE INVENTION
Longwall mining is one of three underground coal mining methods typically used. A seam of coal which can be suitably mined using longwall mining is typically 1 to 6 meters in thickness and may extend at an angle to the horizontal. To enable coal to be mined using the longwall method, a seam of coal is typically divided into a number of elongated rectangular blocks by forming a network of roads throughout the seam. The roads typically include a series of parallel roads. The roads are typically straight, although their height varies according to variation in thickness of the seam of coal, The roads are formed so that their height, where possible, is equivalent to or less than the thickness of the seam of coal.
Referring to
FIG. 1
, the network of roads typically includes roads A
1
and B
1
and a series of approximately parallel roads
1
,
2
,
3
,
4
. . . n which are approximately normal to roads A
1
and B
1
. Road A
1
can include any number of adjacent, parallel roads and is formed first. Roads
1
and
2
are then developed and the development of road B
1
usually follows the development of roads
1
and
2
. The development of roads
3
and
4
are typically positioned close to each other as are roads
1
and
2
. Roads
2
and
3
are typically separated by a much larger distance to define an elongated rectangular block of coal, namely block A of FIG.
1
. Although the network of roads typically includes pairs of closely positioned, approximately parallel roads,
1
and
2
,
3
and
4
etc, a network of roads can include a repeating pattern of up to 5 or more closely positioned, approximately parallel roads which are separated by a sufficient distance to span the width of Blocks A, B etc.
Block A is mined using a longwall shearer which repeats a cycle involving moving a small distance from road B
1
(the top of Block A as viewed in
FIG. 1
) toward road A
1
, and subsequent lateral movement of a plough shear or rotatable cutting drum across the coal face which spans the width of Block A. As the shearer moves from road B
1
toward road A
1
, it mines block A with the use of the plough shear or rotatable cutting drum which moves across coal face, cutting coal from the longwall face of block A. The separation distance of roads
2
and
3
is therefore determined by the maximum lateral movement of the longwall shearer.
Roads
1
,
3
,
5
etc are developed to provide alternative escape routes in the event of an emergency situation. The roads also deliver a continuous supply of air to dilute methane gas. The profile of roads
1
,
3
,
5
etc is typically the same as that of roads
2
,
4
and
6
. As can be seen from
FIG. 1
, roads
5
and
6
are spaced apart from roads
3
and
4
the same distance that roads
3
and
4
are spaced apart from 1 and 2 to create elongated rectangular block B, which has approximately the same width as elongated rectangular block A. The process of developing roads is repeated to create a series of adjacent elongated rectangular blocks.
Roads 1-n are typically formed using a Continuous Mining Machine (CMM) in combination with a Shuttle Car (SC) and a Conveyor Belt (CB). In the case of a series of pairs of roads,
1
and
2
,
3
and
4
etc, as shown in
FIG. 1
, a pair of adjacent roads is usually developed together with a single CMM. The process of creating pairs of roads is typically the same for each pair of roads. For ease of explanation, roads
1
and
2
will be referred to throughout the specification; however, the reference
1
and
2
applies equally to any of the pairs of roads,
1
and
2
,
3
and
4
,
5
and
6
etc of FIG.
1
and also applies to a pair of adjacent roads which form part of a number of closely positioned, approximately parallel roads in road development systems that include more than one alternative escape route and air passageway. A conveyor belt (CB) is assembled in road
2
to extend along the longitudinal length of road
2
as it is being developed and hence extended by the CMM. Coal which is mined from the CMM is transferred to the CB by a SC. Each pair of roads is developed so that lateral roads link roads
1
and
2
. The lateral roads are also formed by the CMM and are typically developed by mining, with the CMM, from road
2
to road
1
. One method typically used to develop roads
1
and
2
and the lateral roads is as follows:
(a) The CMM mines road
2
so that it extends beyond the end of road
1
and a recently formed lateral road, with the SC making frequent trips between the CMM and the end of the conveyor.
(b) The CMM then retraces its path along road
2
until it reaches the most recently formed lateral road and moves to road
1
via this lateral road and subsequently mines road
1
so that its blind end is approximately laterally positioned relative to the blind end of road
2
.
(c) The CMM then crosses over to road
2
to develop a lateral road which extends between blind ends of roads
1
and
2
.
(d) The CMM then retraces its path along the most recently formed lateral road until it reaches road
2
.
As the above cycle is repeated, an end of the CB which is closest to the CMM is moved along the length of road
2
to follow the CMM as it mines and hence extends road
2
. However, the CB is not extended beyond a lateral hole until the next lateral hole is developed. The SC constantly moves between the CMM and the SB, as the CMM develops roads
1
and
2
and the lateral roads.
The efficiency and hence productivity of the CMM is greatly reduced by any movement of the CMM in the above described steps a-d which is not for the purpose of extending roads
1
or
2
or the lateral roads. That is, any movement between roads
1
,
2
or the lateral roads, as well as any movement which requires the CMM to retrace its path, has a substantial negative impact on the productivity of the CMM. Because the productivity of longwall mining is limited by the speed with which the roads are created, it is desirable to provide a more efficient method of roadway development for longwall mining. It is therefore also desirable to provide apparatus suitable for implementing an improved method of roadway development.
OBJECT OF THE INVENTION
It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.
SUMMARY OF THE INVENTION
The present invention provides a method of roadway development for longwall mining comprising the steps of:
(a) developing first and second substantially parallel roads;
(b) joining first and second roads with lateral tunnels which extend laterally between the first and second roads and are positioned at predetermined distances along the longitudinal length of the first and second roads; and
(c) transporting material mined in the process of developing the first road to the second road, via one of the lateral tunnels for transportation along the second road and subsequently out of the mine.
The step of joining the first and second roads with lateral tunnels preferably comprises the steps of:
(a) forming a blind hole which extends laterally from the second road; and
(b) extending the first road to intersect a blind end of the blind hole to result in the lateral road joining the first and second roads.
The second road is therefore preferably developed ahead of the first road so that lateral tunnels, which extend from the second road, do not intersect the first road until the first road is subsequently developed or extended. The subsequent development of the first road results in the first road intersecting a recently formed lateral tunnel. The material mined in the process of developing the-first road is preferably transported, via a lateral tunnel which is closest to an end of the first road which is being mined. An auger which may be used to transport material which is mined in the process of developing the first road, to the second road is therefore preferably moved along the first road in the direction in which the f
Leisemann Bret Edward
Seear Peter Kenneth
Cutting Edge Technology Pty Ltd.
Kreck John
Ladas & Parry
Shackelford Heather
LandOfFree
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