At the end of the project, four main technical achievements can be presented:
- a rubber moulded diamond wire giving significant rise in the cutting performances,
- a diamond wire rotation control device, named "Girafil", enabling a regular wear of the diamond wire, improving by this its output,
- a methodology of designing the granite quarries, based on granite geostructural studies,
- an economical survey, based on the "in situ" value concept, showing the benefits for the quarry owners to extend the use of the diamond wire.
This research programme is designed to improve the yield, i.e. the recovery and value of saleable dimension stone, from 'granite' through improved diamond wire technology. Most such quarries currently recover something between 5% and 15% of the total stone mined as saleable polished stone product. There is thus room for improvement which could reduce the environmental impact of the quarry, improve its product to waste ratio, increase its cash flow and reduce its costs per unit of product. The programme is in three parts. The first part of the research will concentrate on the improvement of the cutting of the stone by the use of the diamond wire saw. At present, diamond wire sawing is not used in all granite quarries and is then usually used for the primary cuts only. This research is designed to improve the cutting efficiency of the diamond wire in granites to enable its use to be secondary and even tertiary cutting in the quarry and in the stone yard. Firstly new diamond wire technolgy, such as thinner wires, will be investigated with a view to improvements in the performance and economics of wire use. Secondly the actual cutting mechanism in the granite and its relationship to the mineralogy and geoparameters of the ore will investigated as it is possible that directional cutting related to crystal orientation for example could improve cutting performance. In the stoneyard, diamond wires offer advantages of less noise, accurate cuts, higher cutting speeds and the ability to cut any size of block as compared with other methods. This research aims to improve these advantages while improving the economics. In the second part of the research programme work will be done on primary cut optimisation which involves, firstly geoparametric research into the 'orebody' designed to characterise the 'orebody' in geological and physical terms. This research will investigate the predictive tools available for defining the likely 'good' granite for recovery and the orientation of the cuts for maximum good block production. Comparisons will then be made between diamond sawing of various types, jet piercing and drill & blasting, or any combinations of these methods, for taking the primary cuts. This will involve test work in actual quarries from time to time. The planning and scheduling of block production from the above data will form the third part of this research programme.
Funding SchemeCSC - Cost-sharing contracts
36201 Vigo (Pontevedra)
SW7 2BP London