One of the biggest inefficiencies in the continuous mining process is waiting for a batch haulage unit to arrive and get into position.

A customer in the Midwestern United States recognized this inefficiency in its own operation, but could not achieve long-term results because whenever they focused and improved on one aspect of the process, the inefficiency seemed to take another form.

Solution design 

Integrating its products, services, experts and processes through JoySmar Solutions, Joy Global began tracking the mine’s “Time between Haulers.” By tracking the time from when the conveyor on the continuous miner was turned “OFF” until the time the conveyor was turned “ON,” Joy Global experts were able to determine wait time.

Process analysis revealed that the process to schedule the feeder move was based on availability of the night shift crew. With four active units at this mine, the crew was moving one of the units every night. Prioritizing was more of a first come, first serve.

Pulling data from the machines for analysis, JoySmart Solutions experts were able to reveal the important tie between wait time and feeder location. A benchmark average of 44.2 second wait time between cars was set, and the solution developed from there.

Through the use of comparison data between units the optimum feeder location was determined. Production rates were used to pace the units’ rate of advance and determine an optimum move schedule.

Results

By the end of 2014, comparison data showed a nearly 2-second improvement in wait times. By reducing the wait time between haulage units per continuous miner, per shift, over the year prior, from 44.2 seconds to 42.7 seconds, on average, the savings began to add up.

With eight continuous miners running daily, the tons added through wait times reduced came to an additional 66,150 tons produced per year.

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