Caterpillar tested a shield from the Kotinskaya mine and the results showed that the roof support condition justified an additional 30,000-cycle life extension with only a minor rebuild.

Over the past eight years Kotinskaya’s longwall face has achieved repeated production records at regular intervals, producing more than 28 million tons of coal and running through the shields 30,000-cycle lifespan.

The 30,000-cycle test run performed at 10% overload confirmed that “the face equipment at the mine should be good for another 20,000 cycles without the need for any major rebuilding”, according to a statement from Caterpillar.

“The tests also show that with only minor rebuild work, the shields will carry on for another 10,000 cycles beyond that – effectively doubling their lifespan at minimal extra cost to Kotinskaya.”

To date, the only significant alteration that has been made to Kotinskaya’s shields has been an upgrade which enables the shields to be operated automatically.

The Kotinskaya mine is operated by the Siberian Coal Energy Company, Russia’s largest individual coal producer, with an output of 97.5Mt in 2012.

Kotinskaya mines thermal coal from the Sokolovskoe coalfield within the Kemerovo region of western Siberia.

Kotinskaya’s longwall is equipped with 1.75m-wide, two-leg Cat shields that have support capacity of 725t each.

With an operating range of 2200mm to 4800mm, the supports are used in a seam that is typically more than 4m thick on face panels that are 230-250m long.