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An Unofficial History of Coal Mining in the Illawarra

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TECHNOLOGY  - The history of mechanisation

The Continuous Miner - 1

A History of the American Continuous Miner

Continuous miners have been around since before the start of the 20th century, in fact the English Channel Machine built in 1870 and operated by compressed air, drove 1.5 miles at some 70 feet/day under the English Channel before the project was abandoned for political reasons.

The Hoadley Knight Machine of 1912 reduced coal to nut size. It had an electrically operated rotor with an hydraulic swing and water sprays.

Col. OTooles Machine early 1920s mined 154 tons in 9 hours 47 minutes. Trialled pneumatic conveying of the coal but also reduced it to powder.

1911 - Jeffrey MM32- A a cutter and loader machine
1913 - Jeffrey MM34-A the Jeffrey Entry Driver
1918 - McKinlay Entry Driver UK borer type machine

Two McKinlay Entry Drivers were installed in the New Orient Mine in 1926 and were successful from the beginning.

The McKinlay Entry Driver ultimately became the prototype Marietta Miner by Marietta Manufacturing Co. of Point Pleasant, West Virginia.

The first Marietta Miners were in operation in the late 1940s in the Orient #3 Mine of the Freeman Coal Co.

Ripper Type Continuous Miners:

The first ripper type continuous miners were patented in the early 1900s however were not widely accepted.

A machine developed and built by a Mr. Harold Silver in Denver in 1943 was installed in the Consolidated Coal & Coke Companys mine.

Improved during it's operation this machine was viewed by engineers from the Joy Manufacturing Company in 1946. Obtaining the rights to the design Joy developed 2 prototypes to be known as 2JCM models, the first going into service in January 1948.

December 1948 saw the 3JCM placed in production with 212 being built during the next 18 years. Following the 3JCM were the 4JCM, 1CM, 5CM and 6CM.

The first American miner in Australia was a 4JCM at Huntley Colliery in the Illawarra in 1950.

The advantages of the ripper type miner were its flexibility and its adaptability to various mining conditions. The disadvantages were its complexities, its inability to clean up adequately while advancing the face and its slow mining rate, a function of its small area of face attack.

Borer Type Continuous Miners:

In spite of the success of the McKinlay Entry Drivers at CW & F Coal Co. the units did not gain rapid acceptance , however when the 3JCM was introduced it spurred renewed interest into all kinds of mining machinery.

Prototype production of the Colmol occurred in 1948 with a low boring machine capable of taking 400 tpd from a 48 seam.

Jeffrey Mining Company acquired the rights to these machines and developed several models on the same principle with total machine HP being some 150 190 HP.

Larger boring machines were developed by Marietta, Goodman and Joy.

Marietta produced its first in Aug. 1950, being based on the McKinlay concept.

Clarkson Manufacturing Co. of Nashville, bought out Marietta in 1955 continuing development until itself was taken over by National Mine Service in 1957.

Larger borers were being produced with Marietta Type 675, 375 HP cutting to 76 high x 13 wide. Horse power was increased 450 and the weight to 57 tons, increasing to a machine specially built to mine potash at 250 tons, cutting 8 high and 25 wide. Each rotor was driven by a 400 HP motor, the all up hp climbing to 1900 HP.

Goodman introduced the type 500 miner in 1954, a miner capable of cutting to 7 wide and 132 wide, each rotor being driven by a 400lb motor and total weight being 73,000 lb.

Joy Manufacturing produced the 2BT in 1955, later developing the 2BT6 with 510 HP and weighing some 52 tons.

The use of borer type machines declined in the 1970s due to its lack of flexibility and associated face ventilation problems.

Auger Head Miners:

In 1955 a prototype having dual augers was developed by an A G Wilcox, particularly for low seam operations.

Jeffrey Manufacturing Co. introduced a similar machine in 1960, the 100-L having a chassis height of only 20 inches.

Jeffrey stopped production of the 100-L after the introduction of the low drum head miner in 1972 however Wilcox, by now part of Fairchild Inc. continued to produce hundreds of their low seam auger miners.

The Oscillating Head Ripper Miners:

In 1950 Mr. E M Arentzen, the president of the Lee Norse Company, invented and produced the Roadmaster, a machine consisting of rotating cutter wheels that oscillated horizontally during the downwords stroke.

Mounted on rubber tyres, the machine was quickly altered to crawlers in 1951.

By 1954, model CM36X was being tested with successive machines becoming ever increasingly larger and more powerful.

In 1964 Joy Manufacturing Company introduced the 8CM with hydraulic oscillation and triple bit rings. A lower version was produced in 1967 as the 9CM.

The 1960s proved popular for this type of miner, the chain ripper and borer type miners being on the decline.

The Drum Head Type Continuous Miners:

One of the major problems with the oscillating head ripper miner was the actual oscillating head itself - a relatively high maintenance item.

In 1967 Jeffrey Manufacturing Co. introduced the Heli Miner with a 14 wide, non oscillating cutter head.

Joy produced the 10CM in 1968, the head width being able to be reduced to facilitate the retreat from the face. In 1969, a lower height version was produced, the 11CM.

National Mine Service produced their first drum head miner in 1970 as model 3060.

Lee Norse persevered with the oscillating head design until 1970 later offering a choice of heads on their Norse 10 and Norse 11 models. In 1972 Lee Norse introduced the HH245 Hustler capturing a significant portion of the low seam market in America.

Excerpts taken from E. M. Warner, Director of Engineering, Mining Machinery Division, Joy Manufacturing Company, Penns. USA, 1979, A History of American Continuous Miners (A paper presented at the International Conference on Mining Machinery, Brisbane, July 2-6, 1979 and published in Mine and Quarry Mechanisation, 1979.)