Coal Age

JUN 2013

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The Fletcher® Walk-thru Roof Bolter Concept Most of J.H. Fletcher & Co. (Fletcher) safety and productivity innovations over 75 years have resulted from "brain storming" meetings between miners (Fletcher customers) and Fletcher sales and engineering representatives. Fletcher customers explain the mine conditions that are potential safety hazards to help in developing the bolter design. Between customers and Fletcher representatives, very often a new concept for the roof bolting machine is developed to address safety and/ or productivity issues. The original idea for the "walkthrough" (WT) chassis for the roof bolter came from the mine foreman at No. 37 Mine, U.S. Steel Lynch District, Harlan County Kentucky. In 1983 the No. 37 Mine was in early development, and the seam height averaged ten feet (3.05m). The coal ribs were extremely hazardous. Fletcher sales and engineering people worked closely with Lynch District Chief Engineers in developing the WT design. These WT machines were model DDR high seam roofbolters having the drilling booms arranged for "inside the booms" operator control positions. Elevating operator platforms were incorporated on each drill boom to raise the and Kentucky. Beginning in the early 1990's, wheel and crawler Fletcher HDDR WT have been sold in England, Australia, China, Norway, Canada, Mexico and operators, with the drilling controls, for easy reach of the mine roof. The HDDR WT and other models spread to the U.S. Western states, Alabama, "inside the booms" operators control position concept South Africa. The Fletcher HDDR WT roofbolter is widely used in South Africa where the room and pillar system is the prevalent mining system. The industry surge to develop metallurgical grade coal seams throughout had been developed Appalachia began in the early 2000's and continuing today has been a key previously in 1978 for element in the improved designs on the low seam Fletcher DDR WT. Seam Bethlehem Energy, heights below 50" created opportunities for various improvements in the Ellsworth Division in layout of the Fletcher DDR WT to accommodate men crawling through the S.W Pennsylvania. The chassis as well as material flow issues. inside the booms con- The walkthrough chassis has had many configurations, and many improve- trol arrangement affords ments have been made over the years. Significant improvements are listed the operators protection below in chronological order: from rib hazards by 1. The walkway deck thickness through the length of the chassis was placing the boom struc- reduced from 9 inches to 4 inches. This gives the operator 5 inches ture between the hazard and operator. The limitations of these earlier machines were that the operators were required to walk between the roofbolters and rib to enter or leave the booms control position. However, the design was a significant additional head room. 2. A powered retracting entrance ramp was incorporated at the rear of the chassis. 3. An automated material handling system for loading bolts, resin, and other supplies (assembled outside the mine in trays) onto the machine safety advancement, for the day. Hazardous ribs were and currently are prevalent in many coal mines. Soon after the U.S Steel No. 37 mine bolters were installed, model DDO WT arm feed roofbolters with inside the boom controls were built for chassis. 4. Operator platform back guard was designed to include a "butt rest" which allows the operators to rest their legs. 5. Lower seam Fletcher DDR chassis was improved. Spreading the chas- Westmoreland Coal Co. in Virginia. Fletcher's first model HDDR WT roofbolter was built for Monterey Coal No. 1 Mine in Illinois in the mid 1980's. Soon after, the sales of Fletcher sis out to allow crawl through in low conditions. 6. Rib access booms were developed on all walkthrough models to allow the operator to better position himself in rib and truss bolt installation. www.jhfletcher.com Company Profile - Paid Advertisement

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