Abstract:
In Sri Lanka, Geological Survey and Mines Bureau (GSMB) imposed royalty levy for
aggregate production volume using an equation (indirect method) which utilises the
quantity of explosives for the calculation. Since the equation resulted in higher deviations
and the previous studies emphasise the advantages of photogrammetric 3-dimensional (3D)
modelling (direct method) when determining production volume of bench blast, the present
study focus on investigating its applicability to irregular faced dynamic quarry with uneven
overburden. Pre and post 3D Digital Surface Models (DSMs) of the quarry were generated
using the structure from motion (SFM) algorithm with Real-Time Kinematic (RTK)
positioning system and Pix4D mapper software. Golden Software Surfer 16 was used to
determine depleted rock volume as the difference between pre and post 3D DSMs. Results
indicate a 5.50% deviation of the proposed method from true depleted rock volume
determined by truck measurements due to uncleaned quarry face during the pre-Drone
survey and unaccounted soil overburden removal. Presence of overburden while generating
DSMs can be overcome by pile volume estimation of overburden and decreasing it from
depleted rock volume when calculating production volume. GSMB equation calculated
production deviate -32% from true production due to the unaccounted explosive amounts
which contributed to the production and confirm the suitability of the proposed direct
method (5.5% deviation) for determining the depleted rock volume in open-cast mines.
Citation:
Ariyarathne, R.C.D.K., Samaraweera, S.A.C.V., Maduwantha, L.S.E., Insaf, M.J.M., Hemalal, P.V.A., Illankoon, I.M.T.N., Dharmaratne, P.G.R., Chaminda, S.P., & Lasantha, M.M.L. (2021). Determination of depleted rock volume in open cast mines using photogrammetric techniques for the purpose of royalty calculation. In D.M.D.O.K. Dissanayake & C.L. Jayawardena (Eds.), Proceedings of International Symposium on Earth Resources Management & Environment 2021 (pp. 68-75). Department of Earth Resources Engineering, University of Moratuwa. https://uom.lk/sites/default/files/ere/files/ISERME%202021%20Proceedings_2.pdf