MINERAL RESOURCES OPEN DEVELOPMENT METHOD Russian patent published in 2011 - IPC E21C41/26 

FIELD: mining.

SUBSTANCE: method includes definition of development stages and substages, sequential deposit development by layers downwards by blocks that are drilled over by specified well pattern with known parameters and subdrill and exploded through location of explosive agents (EA) inside them with slope formation with an angle 60-65° at large value of least resistance line (LRL) at vertical wells or second row at inclined wells and large value of mine face length that reaches 3-4 m, and then rock mass is loaded and transported to storage and overload places. At choosing the parameters of well pattern and their drilling there considered is solids structure, their jointing, contents of large joints in the upper section of the layer formed mainly due to EA explosion in well subdrill area from previous explosion. In order to prevent boulders output in slope bottom zone with sloping angle 60-65° there drilled is a row of out-post wells with deviation from vertical line depthward the solid by 5-10°. For creation of steep slope even surface at an angle of 70-75° the wells are given a slope in rupture plane by 10-15° and are drawn together by the distance between out-post wells equal to 0.5-1 m in comparison to working wells pattern, large joints re-crushing in the upper zone is achieved by dividing main charge into two parts. The smaller part is put in lower stemming zone 1-1.5 m high and isolated from the main part by insert of the same height. For better solid re-crushing the upper charges of the wells are exploded by sections 10-15 ms earlier than the lower ones to create supporting loads at the bottom zone and increase explosion total energy for solid crushing. After block preparation in developed layer by the said method there begun are explosion and loading works. The following lower layers are worked out in the same manner.

EFFECT: improvement of solid crushing quality by decrease of boulders output, decrease of average piece size, slope formation that in general improves excavator production capacity and decrease of prime cost of 1 ton of rock mass development.

1 ex, 10 dwg