Anthraxolite is a hard, black lustrous graphitic coal, which has sometimes been confused with anthracite. The two differ in several respects, in hardness (anthraxolite 3-5, anthracite 2-2.5), and in fixed carbon content. The fixed carbon in anthraxolite varies between 75 and 90%. Our experiments however, showed samples with percentages over 95%. The average of samples gave the following results: fixed carbon 77.3%, ash 18%, moisture 3.5%, volatile matter 1.2%, which compares with results of tests done nearly 100 years ago.
Samples of both anthracite and anthraxolite were burnt and their ash content compared, as well as the ease of burning and the amounts of heat evolved. It was found that anthracite burns much better than anthraxolite, while the latter left much more ash.
The story of anthraxolite parallels the early history of mining in the Sudbury Region. In 1833, C.P. Rail accessed the area. Prospecting began. In 1890-91, Robert Bell reported galena and sphalerite in several places. Interest in the mineral possibilities of the Sudbury Basin was sparked by the discovery of anthraxolite on Balfour Township of the then District of Algoma, by J.R. Gordon of Sudbury in June 1896. This was during a search for platinum. He found little platinum. But he did report finding in the Onwatin slate, a black coal-like substance crossing it at various points. There was an outcrop situated not far from Stobie Falls and along the same belt as the faulting.
The owner of lot 10 in the first concession of Balfour township, claimed that the substance was anthracite, while mineralogists maintained it was anthraxolite.
Whatever it was, in a province without coal, this was an important find. Furthermore it had the added bonus of being close to the nickel mines. Experts on Pennsylvania hard coal declared the rocks similar to theirs and prophesied great things. A great coal boom was about to start. The Sudbury area was in for a period of prosperity.
The Bureau of Mines provided a diamond drill. Under the supervision of Gordon, drilling began in February 1897 in black fissile slate 100 feel south of the outcrop of anthraxolite. The vein was struck at 229 feet and proved to be 4 feet thick. This looked promising indeed, but later tests disproved the presence of anthracite and the unsuitability of anthraxolite as a fuel.
In 1922, A.F.A. Coyne, a Toronto consulting geologist, tried again. He talked of employing 35,000 men. In 1926 another shaft was sunk into the side of the old Gordon showings. Again the project failed. Efforts to develop the mines were abandoned in 1927, since neither the Balfour or Fairbank showings proved to be the sought-for coal.
Anthraxolite burns with a brilliant blue flame and great heat, but leaves behind a great amount of ash. It is the ash that presented the problem and which makes anthraxolite so different from the more profitable anthracite.
Anthraxolite occurs with quartz and pyrite in a fissure vein in slates. It is an introduced deposit in which carbon has been concentrated. Experiments have shown that the proportion of volatile constituents were higher than in anthracite. Quartz, (the ash), occupies the space left by the volatile matter. The anthraxolite deposit is thought to have been originally a vein of bitumen, derived from the enclosing black slate, and then losing most of its hydrocarbons and oxygen to become a substance so similar to anthracite as to be mistaken for it.