Diamond wire sawing in ornamental basalt quarries: technical, economic and environmental considerations

The market interest in ornamental rocks commercially referred to as "œstones€" has grown significantly in recent years, particularly regarding basalt. This has resulted in the widespread use of diamond wire equipped with sintered diamond beads for precision sawing in basalt quarries, especially those located in the industrialized countries; it also has the advantage of preventing rock damages. Diamond wire has been widely used in up-line cutting and other sawing works in both marble and granite quarries for decades; therefore, performance data about the use of this tool on these two different types of rocks are widely documented in academic literature. However, for basalt sawing, information pertaining to the use of diamond wire is unavailable due to various reasons, but mostly because of to its relatively recent introduction in the basalt quarries and also to the historical low market demand for processed basalt in the past. This study offers a possible solution to this lack of information and provides a technical, economic and environmental assessment of diamond wire used in quarrying basalt for ornamental purposes. After an overview on the state of the art of diamond wire and on the final use of processed basalt, the study describes the experimental plan and the results. These show a tool yield much higher than those measured when diamond wire is used on other silicate dimension stones (e.g. granites). Moreover, the composition of basalt sawdust (sludge) has been analysed in the laboratory and has indicated the absence of polluting materials related to tool wear; therefore, basalt sludge, which is made of water and micronized basalt, can be used as a secondary raw material for the environmental restoration of the area or for any other purpose. Further research on other lithotypes is also proposed.