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Powering underground coal mines

World Coal,


Becker Mining Systems has recently been awarded a contract to support an expansion project for a mine in the US Midwest, involving building underground power centres and a longwall electrical system. The operation, expected to produce more than 5 million tpa of coal from 2014, required the utmost in equipment protection to help reduce costly downtime and maximise machine productivity.

Challenge

To meet the needs of the project, Becker required a compact circuit protection solution to protect its customised underground power centres. The breakers needed to support operation of the mine’s conveyance systems, which help transport coal from the underground operation to the mine’s surface. The breakers also needed to meet the mine’s specific space requirements without sacrificing performance.

“Our electrical equipment is routinely included in one of the last construction phases of the project, which made expedited delivery that much more important,” explained Greg Sanders, president and chief executive officer at Becker Mining America. “The faster we could provide an engineered circuit protection solution for our power centres, the faster our customer could begin operations.”

Solution

Due to a long-standing relationship between the two companies, Becker turned to Eaton, which had recently introduced new medium-voltage circuit breakers that were specifically designed for mining applications. The Eaton circuit breakers provided the most compact footprint in the industry and could be delivered in six weeks, about half the time of competitive solutions, to help Becker meet the customer’s aggressive timeline.

Eaton showed Becker the W-VACiMB breakers, which incorporated its proven vacuum interruption technology.

The circuit breakers are engineered to operate in a sealed environment with no external arcing, a safety feature for mining applications where hazardous gases may exist. Interruption of the electrical arc in a sealed vacuum chamber is the safest choice for confined-space mine operations.

Alternative technologies using sulfur hexafluoride (SF6) gas can be a very dangerous choice, as a combination of SF6 gas with an electrical discharge produces toxins that can be fatal. Incorporating vacuum interrupters encapsulated in epoxy resin, the Eaton circuit breakers are protected from mechanical impact, vibration and environmental contaminant – increasing durability and performance in a compact footprint.

Furthermore, the newly designed mechanism assembly in the W-VACiMB has fewer moving parts and requires minimal service during its proven type-tested life of 20,000 operations. The design of the circuit breakers makes them virtually maintenance free, which is extremely important in difficult-to-access underground mining operations.

Results

Convinced of Eaton’s support and its commitment to stand behind the W-VACiMB solution, Becker incorporated 30 Eaton mining circuit breakers in its power centres. By using these breakers, the company was able to integrate the industry’s latest circuit protection technology into a compact design that fit the customer’s space requirements.

By providing a solution within six weeks, Becker was able to significantly improve delivery time to help its customer maximise profitability.

“Although these circuit breakers were a brand new technology, we were confident in Eaton’s ability to deliver a robust and reliable solution based on its circuit protection innovation and experience with mining industry applications,” said Sanders. “Together, we were able to engineer and deliver a solution that will support dependable, safe service for years to come.”

Written by Eaton. Edited by Sam Dodson

Read the article online at: https://www.worldcoal.com/mining/22102014/circuit-breakers-used-in-us-underground-coal-mine-1436/


 

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