Company:China Mineral Processing & Metallurgy League
Email: Bonnie@hotminingepc.com
Phone:+86 18252116933
Fax:+86 10 58646590
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Full Mechanized Mining (longwall) on 78 Degree Steeply Inclined Coal Seam
3212 (II) Working Face of
Lushuidong Coal Mine of Guangneng Company of Sichuan Coal Group is located in
the West Wing of Daluowan anticline. The panel length of this coal mine is 550
meters. The length of working face is 110-140 maters. Coal seam dip increases
gradually from north to south, which is higher in the south and lower in the
north. The average is 60 degrees and the maximum is 78 degrees. There is only
one coal seam with an average thickness of 2.5 meters. The large dip angle of
coal seam mining is very rare in China and even in the world. Under such
conditions, 3212 (II) fully mechanized coal mining face of mining team 1 produced
27985 tons of coal in October, an increase of 12985 tons compared with
Guangneng's initial target of not less than 15,000 tons. For two consecutive
months, a new high output has been achieved, which marks the initial success of
the steep inclined fully mechanized mining project to tackle key problems in
Lushuidong Coal Mine.
The Lushuidong Coal Mine was
completed and put into operation in December 1981. It has been mining for 37
years. The shape of the coal seam in this mine is like "M". Two anticlines
are intersected by one syncline. And the deeper the mining, the greater the dip
angle of the coal seam. As mining time goes by, coal reserves of 50° and below
become less and less, and an average inclination of 60° and above will become
the normal. There is no precedent for China to implement mechanized
comprehensive mining at such a large dip. There is no relevant literature as
well. Before mining, engineers and technicians do not have full confidence in
mechanized mining for such a large dip.
According to the actual
situation of coal seams occurrence in the 3212 (II) working face, generally the
traditional mining methods use the flexible shield blasting technology for
extraction. Since the successful application of the large dip angle fully mechanized
mining in 1997, the mine has been using fully mechanized mining. At present,
there are very few workers familiar with the flexible shield blasting
technology. Moreover, the use of flexible shield blasting technology on the
working face with such a large dip angle would not only face the problems of
bad mining environment, which harms the health of employees, but also the low
production and difficult safety management.
The fully mechanized mining of
3212 (II) working face in Lushuidong Coal Mine has attracted great attention
from the leaders of Guangneng Company. They have listened to the report of the
mining plan and went to the site several times for investigation and
demonstration. Finally, they have agreed to tackle the key problems of fully
mechanized mining at 3212 (II) working face. They have joined hands with the
machinery and mining experts from Beijing HOT Mining Technology Co., Ltd to
gather wisdom to ensure success in solving problems.
There are many technical
problems to be solved in installing fully mechanized mining equipment on steep
inclined working face with slope of 60°—78°. For example, how to prevent
hydraulic support, shearer, scraper conveyor and other equipment from falling
and sliding? How to prevent gangue and rib spalling from hurting people? How to
prevent the support from stringing and sliding? Many problems remain to be
solved one by one.
The gangue board and the
airbag designed by Beijing HOT Mining Tech Co., Ltd. have solved the
problem that the gangue can hurt people when they enter the machine
channel. The problem of people falling down and hurt has been solved
increasing the density of the gangue gate between the supports. The difficult
problem of the support and conveyor sliding in the working face has
been solved by increasing pump pressure and changing production
technology. The improved shearer developed by HOT Mining has made the
performance of anti-running and braking more than double. By improving the
strength of the middle groove 8 word ring, the problem of the middle
groove bulgs caused by the breakage of the 8 word ring will be eliminated,
the problem which affect the smooth running of the shearer. The
improvement of the internal structure of the end support solves the difficulty
of pushing the end support and the problem of effectively connecting the roof
when the working face is super high. The improvement of the lifting seat of the
end support solves the difficulty of the end support lifting. The safety
passage of the end support outlet of the working face is designed
independently, which solves the safety problem of the exit personnel walking.
The problem of easy burning of shearer motor has been solved by adding
anti-collision device of shearer motor and increasing safety factor of flexible
shaft. The improvement of the lifting seat of the shearer rocker arm solves the
problem that the oil cylinder nozzle is easy to be damaged. The shallow
hole blasting and retracting technology are implemented in the advanced
support of the wind tunnel, which basically solves the problem of large-area
empty roof in the corner goaf of the working face.
It becomes a serious problem
that how to safely install the fully mechanized mining support that each weighs
23 tons on the open-off cut which is dangerous as the cliff.
On the night shift on May 31,
the 5th Coal Mining Team began to install the first face end
support.The mine director Chen Shengming personally attended the command,but
when the support is lowered to 28 meters below the exit, the load-bearing track
on the floor was broken, the center of gravity of the support shifted and
slipped out of the track.Handling overweight support is a dangerous and
difficult task.Cheng shengming command the site people to raise the bracket
onto the road on steep slopes where it is difficult for people to stand.
However, the same problem occurred again and again in the process of lowering,
crushing three places on the track, and the face end support was not put in
place until the night shift on June 1.
This installation method is
time-consuming, laborious and unsafe, so the mine leaders decided to
reinstall the track of 3212 (II) working face and add two more tracks on the
original basis, leaving only the upper sleeper for those sleepers that exceeds
the height of two sleepers,fully using concrete pouring the lower sleepers
together with floor, installation after acceptance.
On August 6, the installation
of all equipment in the working face was completed. On August 7, the first
equipment debugging of 3212 (II) working face was carried out by the first coal
mining team. On August 12, the test mining of 3212 (II) working
face opened in the expectation of more than 1700 workers in Lushuidong
Coal Mine.
It is the first time to carry
out fully mechanized mining operation on such a steep workface. The operators
for shear and moving scraper and support were very carefully to prevent
improper handling which might lead to slide down and cause accident. But the
results of commissioning were beyond everyone’s expectations. The originally
worried problem about the support sliding down did not appear. Instead, on
August 18, the phenomenon of support shifting up appeared which made 200mm
coal seam could not be cut at the side of head. The first mining team adopt
lower the support, and after two whole days’ adjustment, the distance between
1# support and face-end support returned to normal finally.
During middle shift of 12
October, the support of working face slid down, and caused the scraper conveyor
between 15# and 21# support hunch up. The interval between floor and scraper
conveyor reached up to 0.9m, which made the shear could not go down. The site
manager reported to superior at once and convened special meeting to discuss
how to solve the problem. After 5 days and nights of work, the problem of scraper
conveyor hunching up was solved finally.
Ever since commissioning, the
team of mine overcame several difficulties of working face completed equipment,
such as shifting up and sliding down. During 20 days commissioning in August,
more than 8000 tons commercial coal was produced; in September, the team
produced commercial coal 26181 tons; in October, the team achieved new peak,
and produced commercial coal 27985 tons. During the three months, there was no
accident worse than minor injuries. Since then, the fully-mechanized coal
mining of 3212(II) steep working face stepped towards normal.
HOT Mining tech is delicated
to provide comprehensive solution for hard mining condition, including steeply
inclined, big angle, low coal seam, gas and water burst, old coal mine upgrade
and etc.
Contact Us
Serena Fu
Teresa Zheng
Kira Zhang
E-mail
serena.fu@hot-mining.com
teresa.zheng@hot-mining.com
kira.zhang@hot-mining.com
Skype
Serena20140924
teresa.zheng123
kira.zhangjing
