Abstract: The invention relates to a process for the preparation of spiro[cis-4-(&bgr;-hydroxyethyloxy)cyclohexane-[3H]indol]-2′[1′H]-one derivatives of the formula (I) wherein R1 and R2 are as defined herein, by reduction of a dispiro[(1,3-dioxolane)-2,4′-cyclohexane-1′3′-[3H]indol]-2″[1″H]-one derivative of general formula (II), wherein R1 and R2 are as defined herein, which comprises carrying out the reduction (a) with sodium cyanoborohydride in the presence of a Lewis acid, or (b) with sodium borohydride in the presence of a strong acid.

Abstract: The mining method of this invention is particularly suitable for the underground extraction of large mineral deposits, wherein a subsidiary road is formed perpendicularly to the work face from which the mineral deposit is to be removed. A boundary subsidiary road is formed substantially perpendicularly to the subsidiary road, a first mine tunnel is formed by removing the mineral deposit from the work face along the subsidiary road until the boundary gate road is reached. Then the material around said first mine tunnel is collapsed to fill the same along the subsidiary road and the collapsed matter is consolidated along the subsidiary road. Finally a second mine tunnel is formed along the subsidiary road. The second mine tunnel can be horizontally or vertically adjacent to the first mine tunnel.