METHOD OF PREPARING INUNDATED KIMBERLITE PIPE FOR UNDERGROUND MINING Russian patent published in 2000 - IPC

FIELD: mining. SUBSTANCE: method may be used in preparation for underground mining of inundated kimberlite pipes under conditions of Yakut diamond deposits. Method involves determination of displacement zone round kimberlite pipe caused by underground working of lower horizon, sinking behind displacement zone of main and auxiliary shafts, driving of working over helical line in downward direction round kimberlite pipe, sinking of main and auxiliary shafts for drilling and grouting of holes. Beginning of each turn of spiral working is connected with main shaft, and end of each turn is connected with auxiliary shaft. As working driving advances, grouting holes are drilled. In so doing, center of each next hole is located on intersection of radii r₁ and r₂, with r₁ = k₁ F₁, r₂ = k₂ F₂, where k₁ is coefficient considering nonuniformity of last hole grouting; k₁ = 0.6-1.0; F₁ is actual diameter of grouting zone of the last grouted hole, m; k₂ is coefficient considering nonuniformity of grouting of the last but one hole, k₂ = 0.6-1.0; F₂ is actual diameter of grouted zone of the last but one hole, m. Working is driven under protection of waterproof curtain formed by grouting of holes drilled from previous turn of workings. Drilled for control over reliability of waterproof curtain are control holes from grouted working of previous turn by leading the driving face to region of location of route of working turn. One part of control holes after opening of working by face is extended to air or to air-passage connections. The method provides for preparation for formation of grouting curtain of high quality with low expenditures and short terms of operation performance. EFFECT: higher efficiency. 3 cl, 6 dwg