Abstract: Microcapsules containing a solution or dispersion of a colorant, especially a solution of an oil-solubilized sulfur dye, in an organic liquid having a vapor pressure below 20 mm Hg at 25.degree. C. can be coated on a side of a sheet of paper for use in pressure-sensitive carbonless copy systems. The solutions of the oil-solubilized sulfur dyes, i.e. 1) colored products of the oxidation of a leuco sulfur dye, leuco sulfurized vat dye or reaction product of a leuco dye or sulfurized vat dye with a cationic compound and 2) colored reaction products of a solubilized sulfur dye with a cationic compound also constitute an aspect of the invention, as do microcapsules whose walls contain an opacifying agent incorporated therein.

Abstract: In the mining of various minerals from the earth, large mining shafts extending from the surface down to the deposited mineral layers or seams in the earth can be provided through the use of large diameter bore hole drilling equipment. With the drilling equipment stationed on the surface of the earth, a drilling member is drilled down into the earth for forming a shaft in excess of 10 feet to a depth of at least 2000 feet. As the earth is broken up during the drilling operation, the broken fragments are removed from the drilled hole by a reverse circulation drilling operation. During the drilling operation, the drilling bit is maintained in proper alignment with the shaft being drilled by the use of non-rotating stabilizers having an outer diameter substantially equal to the diameter of the hole being drilled.

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.

Abstract: Minerals, in particular coal, that have been deposited in layers or along seams in the earth can be mined utilizing a large diameter bore hole drilling equipment. With the drilling equipment stationed on the surface of the earth, a drilling member is drilled down into the earth along the seam of the mineral deposit. If the mineral deposit extends at an angle to the earth, i.e. less than 90.degree., the drilling operation is conducted so as to drill at a similar angle to the earth. As the mineral deposits are broken up during the drilling operation, the broken fragments are removed from the drilled hole. After drilling has occurred for a certain distance in a forward direction, a creeping effect is induced in portions of the side walls of the drilled hole. The drilling member is then retracted from the drilled hole in such a manner so as to drill out any mineral fragments in the hole of the drilling member. These mineral fragments are then removed from the hole as the drilling member is retracted.