Landwall Mining Method Design Options

This assignment explores various design options for landwall mining methods. It delves into the challenges associated with each option, such as risk factors like roof collapse and seismic activity, emphasizing the importance of geological analysis and worker training. The report also examines the efficiency and reliability of different methods, ultimately recommending the belt transect method due to its cost-effectiveness and operational advantages. Part 2 focuses on designing a specific landwall system, considering pillar dimensions and strength based on provided data and empirical formulas. It highlights the importance of ensuring design safety and adherence to material strength limitations.

REPORT ON THE DESIGN OPTIONS OF LANDWALL MINING METHOD
PART 1: DESIGN 1
The mining options presented have got a myriad of challenges such as risk factors that must be
analyzed during establishment of standard operating procedures. Admittedly, risks associated
with each mining option have unique characteristics such as accidental collapse of the roof in
areas where reinforcements are not done properly. The cross deep shaft method is often
associated with this kind of risk as the shafts are sunk relatively deeper. Due to the overbearing
weight of the earth movers and the vibration of the machines, areas prone to earth quakes may be
triggered off. The geologists must therefore competently analyze the data from the area using
modern sophisticated tools and software. The identified hotspots must therefore be avoided at all
costs.
Improper and insufficient training of all workers can also be a potential source of problems. The
inexperienced crane operators and drivers may cause damage to people and properties as they try
to navigate the terrain during mining. The entire system of mining must therefore take into
consideration the complex routing of the machinery and equipment to minimize on backtracking
and unnecessary collisions.
Some mines have weaker rocks which could cave in during operation. It is therefore often
required that once an area is depleted, the remnants must be cleared off. The belt transect method
will come in handy in this case.
The above mining design options have got both merits and limitations. The belt transect method
is the fastest and perhaps the cheapest to establish and run. The area identified is worked on in a
rectangular manner before collapsing the weaker walls to give way to new region as movement
is both traverse and longitudinal.
Therefore, in conclusion, we propose the belt transect method which takes into proper account of
risk, efficiency and reliability.
PART 2: DESIGN II
The objectives of this portion are to:
Ensure design incorporates adequate dimensioning based on the given data and can be tested to
ascertain whether or not they are safe
The pillars are also designed to act as barriers so that localization of problems is highly
encouraged hence:
Now, given the following information:
Pit pillar height= 100m
Seam thickness, t= 3.6m
Main gate development dimension:

4headings (3.6x4.5m)
3 pillars (8.0m wide)
Main gate pillar width= 50m
Head and Tail gate development dimension:
2headings (3.6mx 4.5m)
1 pillar (8.0m)
For the purpose of stability and strength incorporation in the design, the following parameters are
checked using the provided data:
By employing the empirical method, the height of the pillar can be checked using the equation:
P= 0.1h+15…(1)
Where P= pillar width (m) and h=depth of the shaft
P= 50m, h= 100m
Taking p=50m, 0.1h +15= 50
0.1h=35
H= 35/0.1= 350m
The design as it stands allows harnessing up to a maximum height limit of 350m hence the actual
height h=100m is safe.
Next, we check the pillar strength whereby it is given as:
P= 276+1379(w/h)
Suppose we design using h=100m, p= 276+1379(50/100)
=965.5MPa
But the material tensile strength available is at 550MPa (hardened mild steel)
Since the required strength is greater than the given material strength, the design will not meet
the minimum strength threshold hence we redesign:
Suppose a height of 350m is used (although more material will be needed);
P= 276+1379(50/350)= 473MPa
This is safe design hence can be used

REFERENCE
B Ramesh Kumar, S Chandrasekhar and B Veera Reddy . (2016). Construction and operation of
high capacity longwall project : Adriyala experience. The Singareni Collieries Company Ltd
Kothagudem.
SINGH, R.N., A.G. PATHAN , A.G. & ÜNVER, B. (no year). DESIGN OF RIB PILLARS IN
LONGWALL MINING BASED ON THEORETICAL AND PRACTICAL APPROACHES.
Available from: http://www.maden.org.tr/resimler/ekler/17c0907e67d868b_ek.pdf