Overview of Highwall Mining. A small Pictorial Demonstration files. New Technology. Solution to unreachable beded deposit. Highwall mining is a remotely controlled mining method which extracts coal from the base of an exposed highwall. The method has the advantage of low capital cost and less lead time compared with a full underground mine, while being capable of producing in excess of 1 million tonnes per system per year.

1. HIGHWALL
MINING
Presentation by: Bikram Pal
Department of Mining Engineering
Kazi Nazrul University

2. CONTENTS
• Introduction
• Brief History of Highwall Mining
• Highwall Mining Method
• Components of Highwall Miner
• Forms of Highwall Mining
• Design of Highwall Face
• Determination of Pillar Width
• Conclusion

3. INTRODUCTION
Mining a visible coal seam by
making rectangular, mainly
parallel, unsupported
drives, using an unmanned
cutter head and coal
transport system,
controlled from a mining
unit positioned outside the
drive, in front of the seam.

4. BRIEF HISTORY OF HIGHWALL
MINING
•Highwall mining in the form of Auger mining
started in 1983 in USA.
•USA has about 50 to 55 million tonnes per
annum coal production from highwall mining.
•First technology in India was introduced on 2010
in Ramagudam II opencast project of M/s
Singereni Collieries Company Ltd.

5. HIGHWALL MINING METHOD
• Highwall mining is adopted for mining flat shallow coal seams.
• An unmanned continuos miner is driven underground and operated in front of the highwall
• The miner stands on the pit floor or on the bench directly in front of the exposed seam
• It makes long parallel rectangular shaped drives into the coal seam
• The remotely operated cutter module is pushed into the seam by a string of pushbeams.
• Coal is transported from coal face to surface by the contra rotating augers housed inside the closed boxes of push beams or
other mode of transport like chain conveyor etc.
• Coal face is supported by a series of web pillar placed between two highwall drives.
Figure: CAT® HW300 Diagram (Hansen and Kelly, 2014).

6. COMPONENTS OF
HIGHWALL MINER
• Cutting head
• Cutter module
• Push beams
• Material transport unit
• Reels and chains
• Base unit
• Power source
• Discharge conveyor

7. CUTTING HEADS

8. AUGER TYPE

9. FORMS OF HIGHWALL MINING
1. Contour mining of outcrop seam
2. Highwall mining from trench
3. Highwall mining in benches
4. Highwall mining from surface mines

10. FORMS OF HIGHWALL MINING

11. DESIGN OF HIGHWALL FACE
To Design a Highwall
mining face layout:
1. Web pillar width
2. Number of web pillars
between barrier pillars
3. Barrier pillar width

12. DESIGN OF HIGHWALL FACE
Input design parameters
(unchangeable):
1. The highwall miner width of cut
(hole for augur)
2. The mining height (height of
cut)
3. The overburden depth
Considerations:
1. Estimated coal pillar strength
2. The applied stress on pillars
3. The pillar stability factor

13. DETERMINATION OF PILLAR WIDTH
For long pillars (length>>width), as per Mark-Bieniawski formula
SPW= 𝑆𝑖 [0.64 +
0.54 ∗ 𝑊
𝐻
] SPB= 𝑆𝑖 [0.64 +
0.54 ∗ 𝑊′
𝐻
]
Here,
SPW= Web pillar strength (MPa) SPB= Barrier pillar strength (MPa)
Si= Insitu coal strength (MPa) H= Height of cut (m)
W= width of web pillar (m) W’= Width of barrier pillar (m)

14. DETERMINATION OF PILLAR WIDTH

15. CONCLUSION
• Highwall Mining is still a new mining technology for India
• This is efficient and economic means of mining
• Solution for thin seams
• Adoption in larger scale (considering positive results)
• Immediate roof and immediate floor strength and physical properties must be well
studied
• Mark-Bieniawski equation must be considered in pillar designing

16. THANK YOU