Glen Douglas
Glen Douglas Mine is a mature open pit that has been in operation since 1957 and produces metallurgical quality dolomite construction aggregate and agricultural lime. RoM tonnes are in the order of 1.45Mtpa with a product yield of 94%. Of the total sales 50% is metallurgical dolomite supplied to Mittal Steel works at Vanderbijlpark in Gauteng and Newcastle in KwaZulu-Natal. A further 43% is supplied to construction aggregate producers and the balance of 7% supplied to farmers as agricultural lime. The major contract with Mittal Steel is currently being renegotiated. Transport of sales product is either contracted out or the responsibility of the buyer.
Production cost per RoMt was ZAR44.92 in 2004 and is planned at ZAR45.39 in 2005. The average price ZAR/t (FOR) was ZAR53.16 in 2004 and planned at ZAR54.0 for 2005. The mine has sufficient reserves of all products to sustain a mine life of 30 years.
Glen Douglas Mine is an open pit operation producing from a single excavation sub-divided by a 40m wide dyke zone into two pits, the B and C Pits. The C Pit is the main source of the low silica metallurgical dolomite and the B Pit supplies the high silica aggregate. Agricultural lime is produced as by-product from fines collected in settling ponds at the washing and screening plant.
The mining method comprises conventional drill, blast, load and haul using 7 x 50t Cat 773B diesel trucks and 2 x Cat 990 front-end loaders owned by Glen Douglas Mine. All ore and waste is drilled with 115mm blast holes and charged with bulk emulsion explosives. The strip ratio is 1.25 : 1 with bench heights of 14m. All ramp and haul roads are 25m wide at an inclination not exceeding 8.3%. The mine operates on a 3-shift basis over 5.5 days per week. There are community constraints on certain activities. Loading of waste must cease at 10pm and loading of dolomite at 23:00. These operations recommence at 06:00 the following morning. A significant amount of large rocks are evident in the bottom of the B Pit and the upper levels of both pits. These are a result of the low powder factor (0.18kg/t for six months to 30 June 2005) used, in an attempt to reduce the effects of blasting on the nearby community. Mining is affected by the presence of mud pockets that are exposed unexpectedly in the faces that contaminate the ore. The mud pockets also affect the blasting operation resulting in big rocks. All plant and equipment is maintained by mine personnel.
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