800HP Motorized Pulleys at the Westmoreland coal mine, Wyoming USA

Coal mines and thermal power plants have used Rulmeca Motorized Pulley conveyor belt drives for more than 60 years.  From Kazakhstan to the US to Thailand, on every continent, mine and plant operators have learned that Motorized Pulley technology is reliable, safe, and easy to install.  The Westmoreland Kemmerer, Inc. coal mine in Kemmerer, Wyoming is a 13,400 acre opencast mine complex which currently produces coal in three active areas from 12 primary seams and splits.  It opened in 1881 as the Twin Creek underground mine to work the Adaville Formation and opened the Elkol Underground Mine in 1950.  The mine supplies approximately 2.8 MTPY of coal to a 700 megawatt thermal power plant, adjacent to the mine, via a 4,200 ft long overland conveyor.


Operational challenge
Faced with an aging silo reclaim conveyor and 20 years of coal in reserve, the mine decided to improve plant efficiency and plan for the future, by upgrading a problematic drive system on the 450 ft long 54 in wide inclined #130 conveyor in 2015.  Fed by three weigh belt feeders beneath three silos at a rate of 1,600 tph, this convex conveyor feeds the overland conveyor as well as a truck loader.

Eventually, the exposed drive system became unreliable due to chronic coupling failures (requiring weekly re-welding) and occasional pulley slippage. Slippage was most prevalent during winter weather temperature, which can approach -30°F.

In addition to improving conveyor reliability and performance, mine management has a strong desire to improve working conditions for plant personnel while reducing the cost of maintenance as much as possible.


Quick Installation
Conveyors & Equipment of Salt Lake City, UT suggested that Kemmerer Mine consider a Rulmeca Motorized Pulley to replace the aging #130 conveyor drive in 2015.  By December of that year, one 180 HP model 800HD Rulmeca Motorized Pulley was installed in the conveyor head position (Figure 3).  The installation crew only required one shift to install the 5,700 lb Motorized Pulley thanks to the pulleys’ compact size, light weight, and ease of alignment.  Time-consuming drive component alignment was unnecessary because all drive components are internal and pre-aligned.

Kemmerer Mine Maintenance Superintendent, Jerry Schinke, said, “The actual install of the Rulmeca Motorized Pulley was quick and painless. There was a noticeable drop in the noise level and I am looking forward to the heat from the pulley keeping the belt ice free.”

Motorized Pulleys, in general, increase system reliability, lower maintenance expense, improve personnel safety, save space, and reduce power consumption because they enclose all drive components within an oil-filled and hermetically sealed pulley shell.

The Kemmerer Mine’s adoption of Motorized Pulley technology is part of a local trend, which began in the trona mines in southwestern Wyoming several years ago in both surface and underground conveyors.  The acceptance of Motorized Pulley technology throughout the US, across Europe, and in Asia began slowly in the 1980s but has accelerated in this century.

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