JUSTIFICATION FOR THE REQUIRED SPEED OF TUNNEL PENETRATION WHILE OPENING DEEP HORIZONS OF THE NYURBA QUARRY BY JC «ALROSA»

Abstract

Nyurba quarry of JC “ALROSA” to a depth of 750 m, the depth of known reserves, has been offered. The technology includes two stages: modifying the traditional scheme of opening at the depth of 370 m to a circuit opening steeply inclined ramp (21-25%) while using all-wheel drive dump trucks CAT-745C with lifting capacity of 41 t and transition at the depth of 530 m to the opening by a spiral-shaped road tunnel, made outside of displacement area. The main parameters of the innovative opening scheme are given. The proposed technology allows to increase the angles of slopes of non-working sides of the quarry from 45-48 degrees to 57-75 degrees, to reduce the volume of overburden to 3-8 times and to refine effectively the mineral reserves.
Particular attention has been paid to the justification of the required speed of tunnel penetration which has a decisive impact on the effectiveness of the proposed opening scheme. The method of calculation of the required speed of penetration, taking into account the speed of the pit recess, slope of roads, the vertical distance between the portals of the tunnel, the inclination
angles of the working and non-working quarry sides and the direction of the recess. It has been defined that in the conditions of the Nyurba quarry the required speed of penetration should be not less than 19.7 m/month. The use of modern heading equipment on the basis of selective action heading machine AM-105 of the company “Fest Alpine” provides a maximum rate
of penetration up to 60-70 m/month. It has been determined that by reduction of the tunnel incline from 20% to 5% the necessary speed of penetrating increases 2,4- 3,0 times and approaches the maximum possible under specifications. This coases the need and efficiency of the use of all-wheel drive dump trucks and increased slope at the tunnel opening of deep horizons of kimberlite open pits.