Ok Tedi is in a period of transition. By 2008 mill feed will consist of higher levels of high-grade but metallurgically challenging skarn ores. Additionally, the Taranaki pit will start production in 2008 along with the start-up of a new pyrite concentrator. Taranaki ores are very high in sulfur. Sulfur is captured in a pyrite concentrate prior to tailing entering the Ok Tedi River. These and other complex scheduling issues will need to be resolved over a critical three-year period. With these requirements in mind, Ok Tedi contracted AMC Consultants to develop a custom version of the Life of Business Optimisation System (LOBOS) to assist medium-term production scheduling at Ok Tedi. LOBOS utilities enable Ok Tedi planning engineers to: import polygon-based reserve data (Blast Masters) from MineSight's Interactive Planning Tools (IP Tools); graphically construct block sequencing and material flow constraints; edit constraints defining standard scheduling, processing and financial relationships; define dump and stockpile attributes; and assign capacities to production systems, plants, dumps and stockpiles._x000D_
LOBOS converts Ok Tedi's production scenario into a mixed integer program (MIP) and submits the resulting model to Ilog's Cplex MIP Solver. The Solver seeks an optimal production schedule that maximises net revenue per mill hour while meeting all constraints. This paper introduces Ok Tedi and its production requirements and relates these requirements to the facilities developed for an Ok Tedi version of LOBOS._x000D_
FORMAL CITATION:Smith, M L, Horacek, D and Sheppard, I K, 2007. Optimisation of Ok Tedi's medium-term production schedules using the life of business optimisation system (LOBOS), in Proceedings Sixth Large Open Pit Mining Conference 2007, pp 145-152 (The Australasian Institute of Mining and Metallurgy: Melbourne).