ABSTRACT
Waterjet mining at lower pressure, i.e., at pressures below 700 bar, has been used in a number of rock cutting operations. Many of these were outgrowths of the work carried out in California during the development of the original technique for hydraulic mining (Chapter 5). One such development led into the extraction of clay and alluvial surface deposits, described above, another has been in mining high quality sand particles, particularly those of larger size [7.1]. There is some advantage to waterjet use for this, under certain conditions. The benefit comes from the other side of the coin which, on its negative side, led to the problems of river silting which arose during the early hydraulic mining in California.
