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IMPROVEMENT OF PRODUCTIVITY IN QUARRYING DIMENSION STONE USING NEW BLASTING AND DRILLING TECHNIQUES

Objectif


Ornamental stone quarrying by drill and blast methods was surveyed. Although a traditional technique, significant improvements were identified during the investigation.
A method for analysis of rock masses, with particular attention to systems of discontinuities, has been cast, so that planning of quarrying works is made in a sound and systematic way.
Numerical modeling has been used to get an insight of the action of explosive on the rock in the typically uncoupled blasting; both dynamic and quasi-static simulations were carried out in a variety of blasthole geometries (cylindrical and notched) and explosive charges. Preliminary critical (maximum) borehole spacings were obtained by modelling.
Laboratory and small scale tests in marble and granite have been carried out to investigate the effect of explosive charge, coupling ratio, notches and fill material on the quality of the cut and allowable blasthole spacing. Some innovative methods, such as blasthole lining with slotted tubes have also been tested in marble. The positive effect of decked charges of black powder has also been observed in granite cutting.
Some case studies have been analyzed in detail, and better use of drill and blast has been put into practice: decking of black powder in granite primary and secondary blasting, notched holes in granite squaring and in marble secondary blasting.
Practical considerations are given for blast cutting in granite and marble. Suitable drilling equipment is found of great importance for good quality blasting, mostly for using notched drillholes efficiently. A preliminary design of a drill-and-notch machine has been developed.
A computer program for the design of quarry operations has been developed.
The proposed research is directed to develop new controlled blasting and drilling techniques in order to improve productivity in quarrying dimension stones. These new techniques are intended to : A) Reduce the formation of microfissures around the blastholes, and B) To increase spacing between blastholes. The results will be summarized in a computer software capable to define the best blasting parameters. The major research tasks are the following :

(i) Analysis of natural conditions of the rock mass; geological and geotechnical parameters.

(ii) Analysis of present techniques; evaluation of stone waste due to the explosive action.

(iii) Theoretical analysis of the fissure formation process, analysis of the gas action of the explosive; numerical simulations methods.

(iv) Study and development of new blasting techniques such as : notched blastholes; ligamented charge holders; shaped charges; blastholes lining with suitable material; and special decoupling materials.

(v) Development of computer software for blasting design.

(vi) Development of practical methodologies for application of above detailed new techniques.

(vii) Definition of the specifications for the design of a new rock drill capable of drilling notched blastholes.

Successful completion should yield productivity increase of the order of 20-30% by increasing the drilling spacing and through savings in stone waste due to radical crack reduction.

Champ scientifique

Programme(s)

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Data not available

Régime de financement

CSC - Cost-sharing contracts

Coordinateur

UNION ESPANOLA DE EXPLOSIVOS SA
Contribution de l’UE
Aucune donnée
Adresse
CLAUDIO COELLO 124
28006 MADRID
Espagne

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Dernière mise à jour: 26 Février 1993

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Permalink: https://cordis.europa.eu/project/id/BRE20315/fr

European Union, 2024