Decreasing ore grades and increasing labor and material costs have seriously eroded the economic vitality of many mining operations. Coupled with global economic stagnation and recession in the early 1980’s, these conditions have forced re-evaluation of operating strategies and methodologies with the objective of remaining competitive in a world marketplace.

An important factor in system design and economics is utilization strategy. This strategy should be developed in the initial stages of the project, since both operating and capital costs can be significantly affected by the selected methodology. Strategy development should include input from operations-experienced personnel to help assure a system easy to operate and maintain and one that can be practically implemented into the mining operation. Equally important, every effort should be made to include technical and operating personnel who will be responsible for operation of the system at the minesite. This can help develop a “bonding” between the system and its users, simplifying startup and increasing system acceptance.

A two-step format was utilized to assist in the equipment design function. Each design and component was first evaluated for commercial availability and suitability, manufacturer cooperativeness, versatility, ease of operation and maintenance, field support, aesthetic appeal, and reasonable cost. The second step evaluated the design or component for simplicity. This criteria was considered to be of major importance, the simplest form usually being the most cost-effective and mechanically sound.

Portable crushing and conveying systems can benefit open pit mining operations by (1) reducing mine haulage operating costs, (2) reducing future haulage capital expenses, (3) permitting more cost-effective mine designs, and (4) providing the opportunity to adjust to changing conditions. They cannot be justified under all conditions, however, and care must be exercised to ensure that a thorough and valid evaluation is made for each potential application.

The physical availability of the crusher has exceeded 90% since March of 1984, closely approximating the conventional inpit ore crushers. Vibration of the structure is within acceptable limits, with no metal or weld failures. The crusher microprocessor monitor and control system has performed very well, justifying the use of a four-wire multidrop communications link. Its user friendliness has provided for good operator acceptance and the reliability and modularity of the system segments have given maintenance personnel the confidence required with such a state-of-the-art system.