+Bychkov G. V., Professor, Doctor of Engineering Sciences, Ural State Mountain University.

In the last ten years the Urals region has taken first place in Russia in accordance with volumes of processed stone. The number of the plants has purchased unique foreign machinery equipped with computer controlling centers and destined for producing of highly artistic articles of complicated forms. At the same time productive capacity of the stone-processing plants has not been developed in full measure. Labor productivity is 3-4 times lower than the last one at the analogous enterprises abroad, but the cost of production is higher. Smooth band-saws with loose abrasive (quartz sand), used for sawing of the weak rocks and the rocks of the middle strength, have been replaced by the band-saws armored with the diamond segments. Sawing of the hard rocks is carried out often as before by the steel band-saws with application of the cast-iron shot. But above mentioned saws are replaced today by the gang-saws and lately by the multi-wire sawing machines equipped with the Numerical Control. Productivity of the multi-wire sawing machine, in course of producing of the tiles, more than three times exceeds productivity of the gang-saw with the cast-iron shot. Advantages of the diamond-wire sawing machines are most obvious in producing of large-size articles. Productivity of above mentioned machines in this case almost fifteen times exceeds productivity of the gang-saws with the cast-iron shot. It is evident, that in near future the gang-saws will be completely replaced by the diamond wire machines. Gang-saws have significant shortcomings in comparison with the diamond-wire machines. Foundations and water-purification plants for gang-saws are complicated and capitalcapacious constructions. Sawing of brittle granite with the gang-saws is almost impossible owing to inevitable vibration. At the same time the diamond-wire machines are less metalcapacious ones. They may be quickly re-equipped for producing of the new kind of articles. New module cutting centers replace gradually the ordinary block-cutters for granite. Thanks to combining in time of the vertical and horizontal cutting productivity of cutting increases at least by 30%. It has been determined that life of the diamond tools in the cutting centers increases by 25-30% owing to decrease of vibration loads. Module cutting centers are used at the Urals now. Construction of the machine-tools for processing of natural stone is almost absent in Russia. So, almost all machines are bought abroad. Construction of the machine-tools in Russia has to be directed to projection and producing of the machines for manufacturing of the large-size articles.