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Virginia Administrative Code (Last Updated: January 10, 2017) |
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Title 4. Conservation and Natural Resources |
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Agency 25. Department of Mines, Minerals and Energy |
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Chapter 101. Regulations Governing Vertical Ventilation Holes and Mining Near Gas and Oilwells |
Section 170. Pillars of coal to be left unmined, and other protective measures
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A. When mining using an underground, auger or highwall mining method within 200 horizontal feet of a vertical ventilation hole or a gas well, the mine operator shall submit a plan showing the projected pillars of coal to be left unmined around each hole or well.
B. Pillars shall be situated so that each hole or well is centered within a pillar, and each pillar shall conform to the specifications shown in Table I below, based on the depth of cover above the area being mined. The entries developed adjacent to any pillar may not exceed 20 feet in width without prior approval from the chief. In no circumstances may the most narrow pillar dimension be less than twice the width of the adjacent entries.
Table I
Pillar SpecificationsCover (in feet)
Required Solid Pillar Area (in square feet)
Required Additional Pillar Area (Solid or Split, in sq. ft.)
Total Area Bearing Surface Required (in sq. ft.)
0-149
3,600
3,600
150-249
5,625
5,625
250-349
10,000
10,000
350-449
10,000
5,600
15,600
450-549
10,000
13,000
23,000
550-649
10,000
22,000
32,000
650 or more
10,000
30,000
40,000
Historical Notes
Derived from Volume 17, Issue 20, eff. July 18, 2001.
Statutory Authority
§§ 45.1-161.3, 45.1-161.106, 45.1-161.121, 45.1-161.254 and 45.1-161.292 of the Code of Virginia.