Hadi, Arif Maulana
(2023)
Evaluation of Drilling and Blasting Geometry at Kencana Underground Gold Mine PT. Nusa Halmahera Minerals, North Halmahera District, North Maluku Province.
Skripsi thesis, Universitas Negeri Padang.
Abstract
Blasting is the activity of breaking a material (rock) by using explosives to divide the overburden, dismantle solid rock or valuable material or ore deposits that are compact from the parent rock into material suitable for working in the next production process(Ridho & Gusman, 2019).The blasting geometry applied at PT Nusa Halmahera Minerals (PT NHM) at heading size 5 x 5, which is 0.96m burden x 1.10m spacing, where the fragmentation size of top size fragmentation after obtained from image analysis is 37.32 cm and the average fragmentation of Kuz-ram method calculation is 60.68 cm with a total average of 45 blast holes, and the blasting cost is Rp. 30,723,545. These fragmentation results affect the performance of the feeder mill which can still accommodate rock fragmentation with a size of 70cm. However, the company has a plan to reduce the number of blast holes in order to reduce drilling work time and blasting costs, with the fragmentation size being below the company standard. Therefore, it is necessary to create a new drilling and blasting geometry. From the theoretical calculations, a recommendation for drilling and blasting geometry is obtained with an average burden value of 0.81 m and a spacing of 1.07 m with a total number of blast holes of 39 holes which results in a top size fragmentation after image analysis of 43.53 cm and an average size of fragmentation Kuz-ram calculation of 56.45 cm with a blasting cost of Rp. 27,213,524. This shows a cost reduction of Rp. 3,510,021.
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