Rockbreaking accounts for 60% of the direct mining costs in small-scale mining. When drilling and blasting practices are poorly implemented the process becomes inefficient and dangerous. The introduction of a proven drill and blast system to artisanal mining offers a number of challenges, with safety being considered the backbone of any sustainable operation and a standard that cannot be compromised.The paper is based on a project at an artisanal cassiterite (tin) mining operation in a small village in the Kayonza District in the Eastern Province of Rwanda. A drill and blast programme utilizing industry best practice was introduced at an underground development end; a raise developed at an inclination of 23 degrees. The underground working is accessed via a 17 degree incline shaft with an operating length of 105 m and serviced by a single drum winder. The winder operates at a speed of about 3.5 m/min hoisting two 1 t wagons from the bottom of the incline to surface for tipping (Figure 1).The drill and blast programme was implemented over a three-week period. As part of the work, a number of drilling patterns and cuts were investigated and a recommended pattern for the 1.2 m by 1.5 m raise was established. As part of the implementation process a time study was conducted of the development-related work cycle from the entry examination to the initiation of the development end.The challenges that arose with dry drilling in the schist and mica-quartz rock, as well as the issues of dust and ventilation, are discussed. The paper highlights the challenges and importance of the use of direction and grade lines, proper blast-hole marking and drilling, and the use of the burn cut.As part of the implementation programme, the actual cost of development was established, thereby allowing future mine Introduction of drill and blast utilizing pneumatic rock-drills plans to include accurate estimations of the cost of smallscale development activities. Recommendations are made for further work to ensure that the drilling and blasting operations remain safe and are conducted as efficiently as possible.The initial scope of work for the team of mining diplomates (National Higher Diploma in Mining Engineering) from the University of Johannesburg was to assist with the implementation of drilling and blasting in one of the underground workings on the mine. The raise was selected as high-priority development end, as the raise was urgently required to (1) to provide a second egress for workers in the G1 gallery and B1 stope and (2) improve the ventilation of both working places, as all workings were dependent upon natural ventilation and the use of compressed air for ventilation.Currently, incline and tunnel development is through the use of pneumatic rock-drills (without air legs). The initial incline development work appears to have been excavated and supported in a reasonable manner. The final 30 m of development in the horizontal haulage was poorly developed by contractors. The tunnel was not excavated straight, nor blasted to the in...
Surface mining is generally the easiest form of mining for artisanal small-scale miners, as the mineral of interest is either outcropping or is very close to surface, requiring less effort to access and, to a certain extent, entailing a reduced risk to mineworkers. In principle, the lower the stripping ratio (waste to ore ratio) the greater the profits. Bench mining offers a simple and safe method to exploit a deposit, but requires a systematic approach, with the removal of waste and ore in a sequence.
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