Coal chute refurbishment helps eliminate chronic blockage and wear issues for mining and energy

T.W. Woods' hood and spoon chute designs under construction
T.W. Woods' hood and spoon chute designs under construction

A coal chute refurbishment and redesign service is being introduced by T.W. Woods to help eliminate chronic problems in older chute types, including premature chute and conveyor belt wear, blocking and product spillage.

The service – which complements T.W. Woods new smooth-flowing materials handling transfer chute business – applies to both underground and overland conveyor chutes used with mine and energy plant conveyors typically between 900-1200mm with and up to 1200 tph capacity. It also applies to chutes used by quarries.

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 better and more robust materials, such as high-impact, extremely wear resistant chromium carbides, which make advanced hood and spoon designs possible.

“While many of the improved designs and materials have been around for the last decade or so, many of the older plants around seem to be rusted on to older designs – they just patch them up or repair them as they wear through,” says T.W. Woods Director Mr Tom Woods.

“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.”

Faults in older chutes, mostly due to outdated design, include:

  1. Blocking or hang-up due to fines, clay or sticky material being conveyed. “At T.W. Woods we incorporate self-cleaning features which keep the product flowing through the chutes at the same velocity as the speed at which the discharge belt and receiving belt are moving. This keeps the product moving, reducing slow flow areas and reducing boil -over at the discharge belt, which in turn reduces spillage and chute hangup”.
  2. High Impacts at loading points on chutes, which wears holes through the chute because of constant impact. T.W. Woods designs its refurbished and replacement chutes so as to reduce the impact angle of the material onto the chute. This reduces impacts, reduces noise and keeps the material flowing, rather than bouncing and becoming uncontrolled. “We also recommend chromium carbide material, which is designed to handle the high constant impact and extend the life of the chute considerably by a number of years,” said Mr Woods.

T.W. Woods also incorporates large radius turns into the chute design, which allows material to flow easier and not hang up. This also reduces wear on the chute, extending their life.

“Problems can arise because original mine designers can tend to produce standard chutes of the type they always have without full consultation with the mine owners or engineers.

“An education process is sometimes needed with maintenance engineers on the costs and downtime this can incur,” says Mr Woods, whose company’s new and refurbished chutes have been employed by industry leaders in the Hunter Valley and nationally. “Initially the mine maintenance engineer may have to realize they have a problem with wear, impact, hangup, blocking, spillage and premature conveyor belt wear.

“Once these problems are identified, we partner with the plant to look at the issues affecting particular sites and discuss options to vary the design, to give a longer, lower maintenance life – along with easier and usually cheaper ongoing repair and maintenance, with an easier exchange replacement time/downtime.

“Some traditional mines look at the upfront cost in particular applications and baulk at that – they would rather pay ongoing charges, adding up to a much greater sum, than to pay one sum to address the chronic problem and achieve an overall much lower cost of running the chute.

“But once a refurbished chute 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.”

T.W. Woods products for mineshaft development include shaft liners, drilling tooling and wear plate materials, as well as custom-fabricated wear plate kits manufactured at the company’s new plate processing facility for the maintenance of heavy machinery used in shaft development as well as bulldozers, trucks, graders and loaders.

The company’s new technology includes low-height transfer chutes which feature a conical head developed by mining specialist designers to maintain high volume high flow rates (up to 2000 tons an hour) when conveyors change direction either underground or on the surface.