Method and apparatus to complete horizontal drain holes

摘要

A method and the necessary equipment to form horizontal cased and perforated drainholes for an underground, in situ leach mining operation. After a vertical hole has been formed and cased in the earth, horizontal drainholes are to be drilled from below its casing. The depth and thickness of the ore body which is to be recovered is determined. Following this, the proper whipstock orientation is computed and the horizontal drainhole is whipstocked and drilled from above the ore bed into it. A flexible casing, such as Coflexip pipe, is used to case the drainholes. Perforations or slots are provided for in these casings before they are put in the earth. A special retrievable cement plug, basket, and one-way valve are used to control and direct the flow of cement to the volume between the outside of the juncture at the casings.