The cave-in problem was solved by the method of square set timbering invented by Philip Deidesheimer, a German mining engineer from San Francisco, who had been requested to survey the problem by the owners of the Ophir Mine. Previously, timber sets consisting of vertical members on either side of the diggings (ribs) capped by a third horizontal member to support the back (roof), creating a tunnel (drift). However, the Comstock ore bodies were not veins, but sporadic pockets too large for this method. Instead, as ore was removed it was replaced by timbers set as a cube six feet on a side (ribs), front (face) or top (back), all at the same time. Thus, the ore body would be progressively replaced with a timber lattice. Often these voids (stopes) would be re-filled with waste rock from other diggings after ore removal was complete. By this method of building up squares of framed timbers, an ore body of any width may be safely worked to any height or depth. Deidesheimer was appointed to the Ophir as mine manager for his ingenious idea.