Importance

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Abstract

In the mining of minerals from the earth, it is necessary to drill deep bore holes typically between 3000 and 6000 feet in the earth. In order to protect those entering the hole for additional mining operations, after drilling the hole, the hole is lined with a stack of specially constructed lining segments. These segments are formed of either prestressed concrete or steel. The segments are lowered one at a time into the bore hole so as to build up a stack within the hole, thereby lining the hole. The segments are carried to the hole on a transporter and then lowered by the transporter into the hole. Guide cables are threaded through guide conduits provided within the segments so as to maintain the orientation of such segments during the operation. The weight of the segment as it is lowered is supported by fluid, normally the drilling mud, that fills the hole and the transporter until the segment comes into contact with the top of the uppermost segment on the stack of those segments already placed into the hole. Grout is then placed between the lining segments and the inner wall of the bore hole. The grouting process is periodically carried out after every few segments have been placed into the hole. After the lining operation has been completed, the miners can enter the bore hole for other mining operations.

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First Claim