An Assessment of Ore Waste and Dilution Resulting From Buffer/Choke Blasting in Surface Gold Mines
- Sandia National Labs., Albuquerque, NM (United States)
- ICI Explosives (Canada)
A discrete element computer program named DMC{underscore}BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting (Preece {ampersand} Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions (2-D). DMC{underscore}BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993). Buffer Choke blasting is commonly used in surface gold mines to break the rock and dilate it sufficiently for ease of digging, with the assumption of insignificant horizontal movement. The blast designs usually call for relatively shallow holes benches ({lt} 11 m) with small blastholes (approx. 165 mm), small burdens and spacings ({lt}5 m), often with 50% or more of the hole stemmed. Control of blast-induced horizontal movement is desired because the ore is assayed in place from the blasthole drill cuttings and digging polygons of ore and waste are laid out before the blast. Horizontal movement at the ore waste boundary can result in dilution of the ore or loss of ore with the waste. The discrete element computer program DMC{underscore}BLAST has been employed to study spatial variation of horizontal rock motion during buffer choke blasting. Patterns of rock motion can be recognized from the discrete element simulations that would be difficult or impossible to recognize in the field (Preece, Tidman and Chung, 1997). Techniques have been developed to calculate ore waste and dilution from the horizontal movement predicted by DMC{underscore}BLAST. Four DMC{underscore}BLAST simulations of buffer blasting have been performed. The blasts are identical except that the burden and spacing are systematically varied which also changes the powder factor. Predictions of ore waste or dilution are made for each burden in the blast, assuming no horizontal movement, to illustrate the spatial variation observed.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Financial Management and Controller, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 622487
- Report Number(s):
- SAND-97-2957C; CONF-980210-; ON: DE98001366; TRN: AD-a340 260
- Resource Relation:
- Conference: 24. International Society of Explosives Engineers (ISEE) annual conference on explosives and blasting technique, New Orleans, LA (United States), 8-11 Feb 1998; Other Information: PBD: 1997
- Country of Publication:
- United States
- Language:
- English
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