
Mine Plan and Mine Design by N G nair Malanjkhand Copper Project. sub Level open stopes and VCR Methods of sotpe (Ore Extraction) practiced at Kolihan copper mine and khetri copper mine of of Hindustan Copper Limited.
Web Site Copper Mining in India and Mining Methods Open Cast and Under Ground Mining by N G Nair Published for the benefit of Mining Engineering Students.

| From Mines Plan and section, Khetri and Malanjkhand |
| From Mines Plan and section, Khetri and Malanjkhand |
Some autorites (eg. Higham) condiser it to be a variation of overhand stoping adapted to massive and wide ore deposits. However, the drill holes used in the stopes may be downwarde or in a ring or fan pattern and the stoping method is better treated as a seprate variety of open stping.
The method involves the driving of subleves within the orebody to vertically divide a block to be stoped. Miners working within the sublevel opening drill a pattern of holes, long holes of re.
Vertical pillars are left between stopes on the same level. These are called rib pillars. Horizntal pillars are left to support the main haulage levels. The horizontal pillar for support of the upper level is called crown pillar; the one support of the lower level is called the sill pillar.