Oppong, M. N and Agyei, G.


An analysis of hole deviation and its effect on production at Chirano Gold Mines Limited has been carried out. Chirano Gold Mines Limited employs sublevel stoping and open stoping methods where production holes are drilled in the form of rings. Complete control of borehole directions sometimes was not obtained during drilling. This problem caused shortfalls in the burden, spacing and hole depth parameters. The boretrak instrument was used to measure the drill hole deviations at the stopes during this study. The analysis was based on 29 holes in 5 rings which recorded total deviations of 4.4 m, 1.9 m and 16.8 m in the burden, spacing and hole depths parameters respectively. The result showed 31.2% deviation in the burden, 2.8% deviation in spacing and 3.2% deviation in the hole depth. The effect of the hole deviations on production was portrayed by an increased output of 1965.85 t of materials representing 23% deviation from the planned. This result also showed that there would be ore dilution which may decrease the mill head grade. This undoubtedly would increase the cost of production of the mine through extra energy requirement to blast and to process these waste materials. From the results obtained, it was recommended that more boretrak surveys should be carried out for informed decisions to be made by planners during the preparation of the charge plans. Also, deviations in the toe burden should be minimized by drillers using competent machines to drill accurately. Read full PDF

Keywords: hole deviation, production, burden, spacing, hole depth, boretrak instrument


[1] Manmit, R. and Chinmay, K. P. (2009), “Optimisation of Blasting Parameters in Opencast Mines”, BSc Project Work Report, National Institute of Technology, Rourkela, 79 pp.

[2] Anon. (2010), “Long Hole Drill and Blast Boart Long Year”, Accessed: 2nd November, 2018.

[3] Navarro, J., Segarra, P., Sanchidrain, R., Castedo, R. and Lopez, L. M. (2018), “Assessment of Drilling Deviations in Underground Operations”, Tunnelling and Underground Space Technology, Spain, pp. 255 – 261.

[4] Buaba, M. A. (2013), “Ground Fragmentation”, Unpublished BSc. Lecture Note, University of Mines and Technology, Tarkwa, 122 pp.

[5] Mann, C. D. (1982), SME Underground Mining Methods Handbook, Hustrulid, W. A. (Editor), New York, 362 pp.

[6] Aimone, C. T. (1992), SME Mining Engineering Handbook, 2 nd Edition, Vol. 1, Hartman, H. L. (Edition), pp. 738 – 739.

[7] Villaescusa, E. (2014), “Blast Design Parameters”, Geotechnical Design for Sublevel Stoping, Western Australian School of Mines, CRC Press, pp. 258 – 270.

[8] Haycocks, C. (1973), SME Mining Engineering Handbook, Cummins, A. B. and Given, I. A. (Editors), SME-AIME, New York, pp. 201 – 210.

[9] Anon A. (2009), “Blasting Techniques in Underground Metal Mines”, Accessed: 2 nd November, 2018.

[10] Suglo, R. S. (2012), “Underground Mining System”, Unpublished BSc Lecture Notes, University of Mines and Technology, Tarkwa, 28 pp.

[11] Denkena, B., Bergmann, B., Kaiser S., Mucke, M. and Bolle, D. (2018), “Process-Parallel Center Deviation Measurement of a BTA Deep-hole Drilling Tool”, 4th International Conference on SystemIntegrated Intelligence, Achim, Germany, pp. 230 – 234.

[12] Katsuki, A., Onikura, H., Sagima, A., Mohri, A., Moriyama, T. and Murakami, H. (2011), “Development of a Practical High-Performance Laser-guided Deep hole Boring Tool: Improvement in guiding Strategy”, Precision Engineering, pp. 221 – 227.

[13] Ghosh, R. (2018), “Development of a Geological Model for Chargeability Assessment of Borehole Using Drill Monitoring Technique”, International Journal of Rock Mechanics and Mining Sciences, Vol. 109, pp. 9 – 18.

[14] Ostberg, A. (2013), “High Precision Drilling”, 10th International Symposium on Rock Fragmentation by Blasting, pp. 1 – 6.

[15] Rustan, R. A. (1992), “Burden, Spacing and Borehole diameter at Rock Blasting”, International Journal of Surface Mining, Reclamation and Environment, 6(3), pp. 141 – 149.

[16] Henning, G. J. (2007), “Evaluation of Long-Hole Mine Design Influences on Unplanned Ore Dilution” PhD Thesis, McGill University, Canada, 325 pp.

[17] Anon. (2014a), “Chirano Gold Mine”, Accessed: 2nd November 2018. M.N Oppong and G. Agyei / NIPES Journal of Science and Technology Research 2(2) 2020 pp. 1-10 10

[18] Anon. (2014b), “Chirano Gold Mine”, Accessed: 2nd November, 2018.

[19] Anon. (2014c), “Geology and mineralization”, Accessed: 10th March, 2017.

[20] Diakite, O. (1998), “Ore Dilution in Sublevel Stoping”, Published Thesis, McGill University, Montreal, pp. 3 – 7.