Drilling Construction Technology Used in Deep Overburden Layer of Luanhe Ancient Channel in Hebei

Abstract:

The construction situation of Lujiatuo iron ore mine area is deep overburden layers in Quaternary and Tertiary systems, broken bedrock strata and accidents caused by collapse, sticking, diameter shrinkage and water leakage. The new special soil coring tool was selected for overburden layer drilling combined with conventional bit and special diamond bit; and wire-line core drilling technology was used for bedrock drilling with combination of enlarged borehole diameter, wall protection with high quality chemical grout and thief zone plugging. At the same time, mud performance adjustment and maintenance were strengthened, monitoring and adjusting of drilling pressure, drilling speed and pump amount were enhanced. The original designed hole depth was 1300m and the actual depth is 1408m with borehole curvature of 29°, the average coring rate is up to 80% in overburden layer, 100% in both rock formation and ore bed, the hole completion cycle is 75 days. The requirements of the design program are met and the borehole is evaluated as high-quality one.