Brittleness and Packing Density Effects on Blast-hole Cuttings Yield of Selected Rocks

B. Adebayo


This paper evaluates brittleness and packing density to analysis their effects on blast-hole cutting yield for three selected rocks in Nigeria. Brittleness test (S20) was carried out in accordance with Norwegian Soil and Rock Engineering and the Brittleness Index (BI) for the selected rocks were estimated. The packing density determined from the photomicrograph of the rock samples. The grain size of 45 blast-holes drill cuttings collected from three selected while drilling of these rocks were determined using standard method of America Society for Testing and Materials (ASTM) D 2487. The brittleness values are 50%, 44% and 42% for micro granite, porphyritic granite and medium biotite granite respectively. The result of BI varied from 10.32 – 11.59 and they are rated as moderately brittle rocks. The values of packing density varied from 92.20 – 94.55%, 91.00 -92.96% and 92.92 – 94.96% for all the rocks. The maximum weights of blast-hole particle size retained at 75 µm are 106.00g, 103.28 g and 99.76 g for medium biotite granite, micro granite and porhyritic granite respectively. Packing density values have correlation to some extent with (S20) values hence, this influence the yield of blast-hole cuttings as drilling progresses. The minimum weight of blast-hole cuttings particle size retained at 150 µm agrees with brittleness index classification for micro granite.


blast-hole; cuttings; yield; brittle; index; density

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R. E. Goodmman, Methods of Geological Engineering in Discontinuous rock, Wiley, New York, 1976

E. J. Chaput, Observation and analysis of hard rocks cutting failure mechanisms using PDC cutter, Ph.D. Thesis, Imperial College, London, 1991

P. Nicodeme, Transition between ductile and brittle mode in rock cutting, Rapport de stage d’ Option Scientifique, Ecole Polytechnique, 1997

T. Richard, Determination f rock strength from cutting test, MS Thesis, University of Minnesota, 1999

E. Z. Pozin, V. Z. Melamed, S. M. Azovtseva, “Towards a method of quantitative assessment of the cuttability of coals”, Soviet Min. Sci., vol. 15, 1979, pp. 573–581, 1979

M. Cigla, S. Yagiz, L. Ozdemir, “Application of tunnel boring machines in underground mine development”, 17th International Mining Congress and Exhibition of Turkey, Ankara, Turkey, 2001, pp. 155–164, 2001

R Altindag, “Correlation of specific energy with rock brittleness concepts on rock cutting”, The Journal of the South African Institute of Mining and Metallurgy, Vol. 103, No. 3, pp. 163–171, 2003

H. Copur, N. Bilgin, H. Tuncdemir, C. Balci, “A set of indices based on indentation tests for assessment of rock cutting performance and rock properties”, The Journal of the South African Institute of Mining and Metallurgy, Vol. 103, No. 9, pp. 589–600, 2003

R. M. Goktan, N. G. Yilmaz, “A new methodology for the analysis of the relationship between rock brittleness index and drag pick cutting efficiency”, The Journal of The South African Institute of Mining and Metallurgy, Vol. 105, pp. 727 – 734, 2005

V. Hucka, B. Das, “Brittleness determination of rocks by different methods”, Int. J. Rock Mech. Min. Sci. and Geomech. Abstr., Vol. 11, pp. 389–392, 1974

Z. O. Opafunso, B. Adebayo, “Blast-hole cuttings: an indicator of drill bit wear in quarries”, European Journal of Scientific Research, Vol. 20, No. 4, pp. 721-736, 2008

B.V. Gokhale, “Flushing of Blast-hole”,, pp 1-4, 2004

A. Erosy, M. D. Waller, “Textural characteristics of rocks”, in: Engineering Geology, Elsevier, Netherlands, pp. 123136, 1995

B. Adebayo, J. M. Akande, “Textural Properties of Rock for Penetration Rate Prediction”, Daffodil International University Journal of Science and Technology, Vol. 6, No. 1, pp 1-8, 2011

G. E. Andreev, Brittle failure of rock materials. Balkema/Rotterdam, 1995

A. Borg, Hard Rock Tunnelling Boring in Norway, in: Norwegian Tunnelling Today, Norwegian Soil and Roc Engineering Association, Publication No. 5, Tapir Publisher, Trondheim, pp. 109 – 112, 1988

AFTES, Guidelines for characterization of rock masses useful for the design and the construction of underground structures, Tunnels et ouvrages Souterrains, no. 177, Mail / Juin, 2003, p. 49, 2003

J. S. Kahn, “The analysis and distribution of the properties of packing density and size sediments”, Journal of Geology, Vol. 64, pp 385-395, 1956

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