Mining Board Width and Coal Extraction

This assignment delves into the relationship between mining board width and coal extraction effectiveness. It presents estimations demonstrating that wider boards result in lower coal recovery (4%) due to increased excavation along creases, while narrower boards yield higher recovery (7%) because more coal remains in place. The analysis also highlights how column sizes vary depending on board width to accommodate the load they bear. Narrower boards necessitate smaller columns.

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Part A
The various parameters regarding long wall mining can be discussed as-
Pillar sizes
Room and column mining is a non-subsidence for a mine, safeguarding the valuable farmland
above. It is among the most secure and a standout amongst the most biologically benevolent
ways to deal with mining coal today, making a non-subsidence condition and keeping up clean
water principles.
The extent of the pillar relies upon the quality of the coal creases, the nature of the rooftop and
the hardness floor of the mine, the impact of the gasses accessible in the air and to what extent
the columns should bolster the coal crease, also called the time subordinate strain. At the point
when the coal is solid, the mining operation will require columns with lesser width. The column
edges will be influenced by the quality of the rooftop; if the rooftop is solid, the edges will be
pulverized (Hout & Stein, 2014). The strain on the columns increments with the progression of
time while the heap conveyed stays steady. In this way if the column is not adequate in estimate,
it might come up short regardless of being steady in the beginning times.
Camp affirms that columns are essential for the security of the laborers in the mines in this way
the principle motivation behind the columns that are set at the head entryway section and the last
part passage is supporting the overlying strata. The head entryway is utilized for transporting the
excavators, coal and the provisions while the tail section is utilized for ventilating the mine from
clean. The measure of the columns to be utilized relies upon the thickness of the creases, the gear
being utilized and the profundity at which the mining is to be done (Eberhardt, Woo, Stead &
Elmo, 2015). At the point when the column is too thick, there are misfortunes made since the
coal at the column is not mined. In spite of the fact that there is a probability to mine the coal at
the column as the mining propels, there is still coal misfortune by a negligible rate when
withdraw mining is connected. At the point when the column is too thin, there is the likelihood
that the coal rooftop will crumple into the mining region. The crumple will prompt specialists
being hurt, backing off the procedure because of interruption of ordinary stream of work, and
lost a level of the coal that should have been mined because of aggravation to the strata and the
mistake with clean and other undesirable components. An average column measures six to forty

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five meters in width and six to twelve meters long. To help the help of the columns, extra help is
given by rooftop shooting.
Method of mining
Long wall mining is a very gainful underground coal mining procedure. Long wall mining
machines comprise of various coal shearers mounted on a progression of self-progressing water
powered roof underpins. The whole procedure is motorized. Long wall mining machines are
around 800 feet (240 meters) in width and 5 to 10 feet (1.5 to 3 meters) tall. Long wall diggers
separate "boards" - rectangular pieces of coal as wide as the mining hardware and as long as
12,000 feet (3,650 meters). Monstrous shearers cut coal from a divider confront, which falls onto
a transport line for evacuation. As a long wall excavator progresses along a board, the rooftop
behind the digger's way is permitted to fall (Xu, Mei & Ge, 2016).
Financially, the speculation costs are twice higher for Multi Slice Long wall technique when
contrasted with Long wall top coal folding strategy. Contrasted with the Multi Slice Long wall
strategy, the Long wall Top Coal Caving technique is more successful as it is more temperate as
it requires less work and gear and can be connected to thicker creases all the more effectively.
Created by the French in their coal mining industry, the Long wall top coal giving in strategy has
one face of the crease worked on the base while the coal that is left on top is taken from the
window through the rooftop bolster.
Best sequence for long wall mining
There are two methods for mining coal productively: Mining and progress Long divider
techniques. At the point when the coal is less than six meters profound, the best strategy is to
utilize the single cut Long divider technique. While if the coal mine will be more than 6 meters,
the financial matters security and dependability of the technique ought to be viewed as. For
example if the mining profundity is 20m, the multi cut technique can be utilized 5 times for
crease thicknesses of 4 m or the Long divider top coal giving in strategy can be utilized to
extricate a layer at the base of say 4m and the rest can be permitted to collapse with a specific

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end goal to take into consideration the recuperation of the coal crease that breakdown. Of the
two, the Long divider top coal strategy (Chen, Chang, Sofia & Tarolli, 2015) is best as it lessens
the cost of the operation. The measure of coal lost in the rubble amid the crumple is unimportant
and can be discredited by the advantages collected when contrasted with the assets that would
have been spent exhuming the 4 layers utilizing the multi cut technique. The methodology
utilized amid the mining procedure is process is either withdraw or progress. For the withdraw
technique, the passages are utilized to hinder the Long divider board and once this is done, the
extraction of the coal from the creases starts from the finish of the board and advances towards
the front and fundamental section of the coal mine. In the propel framework, nonetheless, the
mining starts at the fundamental passage and moves towards the finish of the board. As the coal
is evacuated, water driven frameworks and control frameworks are initiated to enable the
transport to advance and transport the coal to the assigned area. Constant improvement on the
two passages on each side that is for all intents and purposes dead work is disadvantageous in the
progress long divider strategy (Xue, Duan & Deng, 2015). This is so as to guarantee that the
sections are both open because of the gob framed when the hollows crumple. The ventilation of
the mine is additionally frenzied while utilizing the progress Long divider technique. The
withdraw strategy is favored as it removes coal from the creases and the ventilation work is
considerably less and there is no requirement for additional dead work amid the procedure.
Panel width choice while mining
Gob inlay includes setting particular material into the mining territory with the end goal of
supporting overburden. For long wall mining, gob inlay is likewise called finish inlay.
Ordinarily, there are three essential challenges for coal mines to execute inlay, of which one is
that the low profitability with inlay can't facilitate the high mining creation. All in all, the coal
profitability of 1 million tons for every year can't be picked up for an entire refilling long wall
confront, which is a long way from the necessities of a high-proficient current coal mine
(Nguyen & Niedbalski, 2016).
It decides the situations of the head and tail sections. Setting up the required machines and work
process relies upon the measure of the board and could take averagely nine to a year. The size
likewise decides the measure of coal that will be removed notwithstanding the kind of gear that

Pit Floor
Down Dip (7 degrees)
7.2 km
6.1 km
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will be utilized. The border cut out for the board ought to take into consideration the persistent
operation of the mine utilizing the gear being used. As a rule, the hardware being used is self-
progressing pressure driven rooftop bolsters, a heavily clad transport line parallel to the coal
divider face to transport (Zhang, Zhang, Han, Qian, 2014) the coal when it mined to the assigned
zone and the coal shearing machine that takes into consideration the coal to be shared and put on
the transport line. Typically, if the nature of the mine is good, up to 80% of the coal being mined
will be recovered. Around the board, there ought to be 10 to 15 feet space left to take into
account adequate space for the excavators to work notwithstanding the gear (Fengyu, Dongjie,
Haiying & Delin, 2015).
PART B
The given diagram of the geometry is as follows-

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Now applying the Simpsons rule for the given geometry as-
Area A=h
3 ( f 0+ 4 f 1+ f 2 )
The given values for the above geometry are as follows
 Pit Pillar (100 m)
 Seam thickness (3.6 m)
 Main gate development dimensions
o 4 headings (3.6 m x 4.5 m)
o 3 pillars (8.0 m wide)
 Main gate pillar width (50 m)
 Head and Tail gate development dimensions (Newcomen & Dick, 2016)
o 2 headings (3.6 m x 4.5 m)
 1 pillar (8.0 m wide)
Now the volume of the coal mine (L = 1000) will be-
Volume of coal mine L= 1000
Width Length Height Volume
1150 3100 3.7 13190500
1150 3050 3.7 12977750
1150 3000 3.7 12765000
1150 2950 3.7 12552250
1150 2850 3.7 12126750
1150 2750 3.7 11701250
1150 2750 3.7 11701250
1150 2950 3.7 12552250
1150 2650 3.7 11275750
1150 2450 3.7 10424750
1150 1450 3.7 6169750

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1150 1300 3.7 5531500
total 132968750
x f(x) h/3 area volume f(x)i
i
h/3 area volume
0 3100 400 2800 400
1200 3050 400 3100 400
2400 3000 400 7640000 26893000 2900 400 7180000 22827000
3600 2900 400 0 2500 400 0
4800 2900 400 7240000 28573000 1400 400 5860000 21295000
6000 3000 400 0 1300 400 0
7200 2500 400 6800000 24957000 800 400 3020000 11023000
20800000 75947000 16100000 57694000
Total Volume 156370000
Pillar volumes
Type of pillar Length Widt
h
Height Volume
Pit pillar 100 100 3.7 37000
Main gate 50 50 3.7 9250
3 Pillars 8 8 3.7 236.8
8 8 3.7 236.8
8 8 3.7 236.8
Total volume 46960.4
Volume Of Seam Coal Using Panel Length As 1400M

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2400 3000 3.7 26640000
2400 3100 3.7 27528000
2400 2900 3.7 25752000
2400 2900 3.7 25752000
2400 2800 3.7 24864000
2400 1400 3.7 12432000
total 142968000
x f(x) h/3 area volume f(x)ii h/3 area volume
0 3100 600 2700 600
1800 3000 600 3050 600
3600 2800 600 1074000
0
39564000 2850 600 1058000
0
3829000
0
5400 2700 600 1900 600
7200 2500 600 9900000 38620000 700 600 6736000 2413400
0
2064000
0
76834000 1741000
0
6251400
0
total volume 137927000
Coal recovered percentages will be-
length of panel volume
(Simpsons)
volume
(panels)
pillar
volume
volume
remaining
% of coal
recovered
1150 135454000 127849000 45702 7794000 7%

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2300 135846000 132846000 45702 5080000 4%
The examination then of the above estimations is that when the boards are bigger, more coal is
mined from the creases and along these lines the sum recuperated (i.e. that remaining parts) is
significantly less, at 4% while with boards of lesser width, more coal remains along these lines
the sum recuperated is 7%. The column sizes likewise change as indicated by the board width
because of the heap they convey. Boards with lesser width require boards that have lesser
measurements.
References
In't Hout, C. W., & Stein, R. T. (2014). U.S. Patent No. 8,876,220. Washington, DC: U.S. Patent
and Trademark Office.
Eberhardt, E., Woo, K., Stead, D., & Elmo, D. (2015, January). Transitioning from Open Pit to
Underground Mass Mining: Meeting the Rock Engineering Challenges of Going Deeper. In 13th
ISRM International Congress of Rock Mechanics. International Society for Rock Mechanics.
Xu, N., Zhang, J., Tian, H., Mei, G., & Ge, Q. (2016). Discrete element modeling of strata and
surface movement induced by mining under open-pit final slope. International Journal of Rock
Mechanics and Mining Sciences, 88, 61-76.
Chen, J., Li, K., Chang, K. J., Sofia, G., & Tarolli, P. (2015). Open-pit mining geomorphic
feature characterisation. International Journal of Applied Earth Observation and
Geoinformation, 42, 76-86.