Drop Raising in Mining (VCR) Method


Drop Raising in Mining (VCR) Methods of Stopes ( Extraction of Ore).
Hindustan Copper Limited has addressed the complex ‘raising’ operation in mining and developed and implemented Drop Raising techniques at 80 meters intervals which improved safety and led to faster and higher productivity. A pattern of five (165mm) blast holes have been standardized for blasting the raises sequentially by the carater method.

Vertical crater retreat (VCR), also known as vertical retreat mining (VRM), reduces the cost of mining wide, steeply orebodies. The stope has a similar shape, but instead of small longholes drilled in fans, large blastholes are drilled vertically from a top sill to break through into a bottom sill on the sublevel below. This allows the ore to be broken into the bottom sublevel in successive horizontal slices using the same blasthole for each successive deck or blast. No slot raise is required. Only the bottom of each hole is loaded for each successive blast. This breaks off a slice of ore from the bottom of the ore block, which falls into the drawpoint level below, where it can be mucked out. Mucking provides room in the stope for the next blast. Dilution is controlled by removing just enough ore to create a sufficient void for the following blast. This mining method is particularly safe, because the miner does not enter the area where the ore is blasted. Drilling and loading are done from the top sill. The method also eliminates the need to support the ground in the stope after each blast. Mucking can be done using  LHDs or by any loading equipment. 
Life goes by too quickly. We are constantly on the move with little thought of what tomorrow might bring. While there may be material things of value that we can leave to our family – all of those “things” will eventually have very little meaning. But our thoughts, our hopes, our dreams, and our memories – those are the true treasures of life! . Sarla Nair India (Copper Mining Family)
Copper Calling - A House Journal of Hindustan Copper Limited
Mr. H R Bharatia Dy. General Manager (Mines), Hindustan Copper Limited with the Blasting team at Khetri Copper Mines, Khetrinagar, Jhunjhunu Dist. Rajasthan State India. Drop Raising in Mining (VCR) Methods of Stopes ( Extraction of Ore). Sarla Nair India (Copper Mining Family)Sarla Nair India (Copper Mining Family)
Hindustan Copper Limited has addressed the complex ‘raising’ operation in mining and developed and implemented Drop Raising techniques at 80 meters intervals which improved safety and led to faster and higher productivity. A pattern of five (165mm) blast holes have been standardized for blasting the raises sequentially by the carater method.
HCL has developed single sub-level method of stoping using large diameter (165mm) blast holes over level intervals of 50 to 60 meters. Excellent fragmentation has been achieved. Benefits of new stoping method has been in reduction of drilling cost and explosive cost, reduction of manpower and reduction in stopes preparation time. 
 
 

Blasting in Mines to improve Fragmentation and Reduce Ground Vibration in Mines - 
‘Blasting in Mines – An Art or a Science?.
Ethics and values in Extraction of Ore from the Earth Crust 

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