Customised underground utility vehicles

Over the years, J.H. Fletcher has established itself as a leading manufacturer of custom-designed equipment. Today, the company provides a wide array of speciality equipment that are direct results of customer-based endeavors. Some examples include the Model 3800 articulated diesel tractor, can manipulator, beam setter, degasification drill and passby bolter.

Model 3800 articulated diesel tractor

The Fletcher Model 3800 articulated diesel tractor is backed by a unique story. Several years ago, a customer approached Fletcher about building a custom version of a machine they had previously purchased from another supplier. At the time Fletcher did not manufacture the machine, but was ready to take on the task. The result was the introduction of an entirely new product line in 2006: Fletcher’s 3800 Series diesel tractor, a vehicle Fletcher commonly refers to as the prime mover.

The standard 3800 Series diesel tractor is designed with a diesel-powered articulating frame to carry and move supplies and other equipment underground. These machines feature fifth wheel or pintle-hook-type hitch, a powerful diesel engine, four-wheel drive and pressurised enclosed cab.

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“This machine is designed to haul supplies in and out of the mines,” said Sean Farrell, Fletcher’s product manager for the prime mover. “It features a trailer with a tongue attached to fifth wheel for moving gravel trailers, water tanks, raw materials and longwall shields, etc. It is basically a utility vehicle for whatever the mine needs. And we design it to perform based on what the customer wants. Grades, weights, axle ratios and engine size are some of the variables that come into play.”

To create an even more custom piece of equipment, Fletcher offers a variety of tractor attachments. These attachments include: battery loader, coupler/pintle hitch, DR bolter, grader blade, loader and prime mover boom.

Can manipulator

The introduction of the Fletcher can manipulator came shortly after it was brought to its attention that operations were purchasing existing equipment and adapting it for underground usage. Many mines use off the shelf gripper mechanisms designed for handling large rolls of paper and then attaching them to other less desirable, but available, carriers. This can result in loss of time, money and, sometimes, unsafe working conditions. With cans increasing popularity, Fletcher saw the importance of creating a piece of machinery specifically for setting longwall cans.

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The Fletcher can manipulator can reduce cycle time by reducing the extra steps and precautions miners had to previously take when setting cans. The Fletcher can manipulator is designed to pick up and set a can anywhere in a normal 20 ft wide entry without moving the chassis of the machine. The design of the machine creates a low centre of gravity, allowing the machine to pick up a 36” dia., 3500 lb can and tram with it secured safely in the gripper. It also provides the ability to set up to 10 ft cans and up to 5000 lb cans, eliminating the need to set multiple smaller cans.

Beam setter

The Fletcher beam setter was designed around the same focus as the can setter: helping relieve miners from dangerous, grueling labour. When a customer was confronted with the issue of using tall square set beams that were difficult to assemble underground and needed to be lifted over and around a 24 in. dia. vent tube and 42 in. wide conveyor, the company knew to contact Fletcher. Fletcher was able to not only provide a machine that did these functions, but also operated in a confined space and allowed for safely installing steel plates and cementitious grout. This was the introduction of the Fletcher beam setter.

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The beam setter allows for safer installation of square set beams over and around vent tubing and conveyer belt systems for slope development. The beam setter is built to transport, place and hold heavy beam assemblies during installation.

Degasification drill

The Fletcher degasification drill was a result of a partnership project. When a customer presented the idea of drilling long horizontal holes to de-gas coal seams, Fletcher accepted the challenge. Through working directly with the customer, the equipment manufacturer helped to develop not only a new piece of equipment, but also a new method for methane drainage.

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The degasification drill is designed to drill horizontally up to 5000 ft (1524 m) into the working coal face for methane drainage, dewatering and seam orientation. These machines vary in torque and thrust capacities according to the application. Fletcher offers machines from 10,000 lb. (4535.9kg) to 50,000 lb. (22,680kg) thrust and typically use "NQ" or "BQ" size drill rods.

Passby bolter

The traditional method of roof bolting in single entry systems has been the use of handheld equipment. But handhald equipment is very limited in its application, and can put operators in dangerous situations. To overcome these shortcomings, Fletcher began work with a customer to develop a very unique bolter: the passby bolter.

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The passby roof bolter is a narrow 54 in. (1.37 m), yet provides the benefits of a much larger bolter. The unique tramming and steering system allows for difficult maneuvering so that roof bolts can be installed after the cutting process. It is designed to work in single roadway developments where multi-entry and place-changing cannot take place.

Adapted from press release by Jonathan Rowland

Read the article online at: https://www.worldcoal.com/product-news/18022014/fletcher_customised_underground_utility_vehicles_coal534/