The colliery had been trying to get a smooth flow of a clay-rich coal through its washery. But chute redesign efforts left coal clogging up the chute that angles down from a feeder bin before the coal is washed.

“The coal wasn’t getting through properly,” a maintenance spokesman for the colliery said.

“We’d had the chute taken out of refurbishment twice already, at a cost that makes me shudder.

“It still wasn’t performing smoothly without the coal sticking. The transfer chute had gullies in it.”

TW Woods Group replaced all the working areas of the chute, remoulding and polishing them.

This removed the sticking points.

The colliery handled two sorts of coal. One type was dry, the other clay-like and sticky.

“The second type was causing all the trouble for us,” the spokesman said.

TW Woods coal chute refurbishment and redesign service was introduced to help eliminate chronic problems in older-type chutes. This included premature chute and conveyor-belt wear, blocking and product spillage.

Refurbishment componentry, including soft-loading chutes in hood and spoon configurations, take advantage of advances in chute design over the past 10 years, as well as robust materials such as high-impact extremely wear resistant chromium carbides. This makes advanced hood and spoon designs possible.

“Many of the older plants around seem to be plodding on, unaware of the latest technologies and how they can help the flow of materials,” TW Woods director Tom Woods said.

“Such plants have a continuous problem with having to employ labour to clean the chutes out and to clean up the spillage they cause, costing time and money.

“Some traditional mines baulk at the upfront cost of upgrading their chutes, but once a refurbished or replacement chute is installed, they usually go on to convert all their chutes over time.

“This has happened at quite a few mines in recent years.”