Blast Impact Prediction Studies at Ghana Manganese Company (GMC) Ltd, Nsuta, Ghana
Keywords:
blast impact, environment, prediction, regulatory thresholdAbstract
Ghana Manganese Company (GMC) Limited has its mining operations currently concentrated in the Pit C area, and the company intends to re-develop the northern extension known as Pit C North, close to Tarkwa-Banso community. Mining of the pits involve both free digging and drilling and blasting of the overburden and the fresh competent rocks respectively. To conduct safe blasting operations in the Pit C North, studies were undertaken to assess the environmental impacts of blast associated with ground vibration, air blast and fly rock at 400 m from the pit periphery. It is however envisage that settlements within 400 m from the pit periphery should be resettled by the Company. Various models were used to predict the blast impact in terms of ground vibration, air blast and fly rock distance. The ground vibration at 400 m from the pit periphery predicted with the USBM model is 0.67 mm/s but predicted with Gustaffson’s model is 1.15 mm/s. Both predicted ground vibration values are below the Ghanaian’s regulatory threshold of 2 mm/s. Similarly, at 400 m from the pit periphery, the predicted maximum air blast based on current drill and blast design parameters of the Mine is 52.17 dB (L). This predicted air blast values is lower than Ghanaian’s regulatory threshold of 117 dB (L). The estimated maximum fly rock throw from Pit C North using the current drill and blast design parameters is 194 m. By adhering to best blasting practices and current drill and blast design parameters for Pit C North, impacts of ground vibration, air blast and fly rock on the neighbouring Tarkwa-Banso community are within the acceptable regulatory requirement for residential areas.References
Amegbey, N. (2009), “Blasting Standards for Ghanaâ€, Unpublished Final Report Submitted to PMU for MSSP, September, 40 pp.
Amegbey, N. (2010), “Assessment of the Impact of Blasting Activities at Pit C North of Ghana Manganese Company (GMC) on Tarkwa Banso Communityâ€, Unpublished Report, GMC, Tarkwa, 7 pp.
Amegbey, N. and Afum, B. O. (2014), “Atmospheric Pollutants Diffusion Studiesâ€, Unpublished Report, GMC, Tarkwa, 48 pp.
GMC-EIS (2012), “Environmental Impact Statement (EIS) for the Proposed Pit C North Project, Ghana Manganese Company (GMC)â€, Unpublished Report, GMC, Tarkwa, 126 pp.
Holmberg, R. and Persson, G. (1978), “Fly Rock and Air Shock Waves in Blastingâ€, Report DS 1978, Swedish Detonic Research Foundation, Stockholm, Sweden, 15 pp.
Kesse, G. O. (1976), “The Manganese Deposits of Ghanaâ€, Ghana Publishing Corporation, Geological Survey Department of Ghana, Tema, Ghana, pp. 13-34.
Kesse, G. O. (1985), The Mineral and Rock Resources of Ghana, A. A. Bulkema Publishers, Rotterdam, pp. 11-33 and pp. 298-321.
Lundborg, N. (1981), “The Probability of Fly Rock Damageâ€, Report DS 5, Swedish Detonic Foundation Report, Stockholm, Sweden, 39 pp.
Ollofson, S. O. (1990), Applied Explosives Technology for Construction and Mining, Applex Publisher, Arla, Sweden, pp. 238-240.
Persson, P-A., Holmberg R. and Jaimin, L. (1994), “Rock and Explosives Engineeringâ€, CRC Press, pp. 375-380 and pp. 383-384.
Downloads
Published
Issue
Section
License
Copyright © 2021 University of Mines and Technology (UMaT), Tarkwa. Ghana