Sydney Coal Field      Geographically, Cape Breton is an island on the Atlantic Seaboard of North America with a total area of approximately 3,981 square miles or 10,311 square kilometres. The whole coast is deeply indented by bays and channels, some of which constitute excellent harbours. Indeed Sydney Harbour ranks among the finest harbours in North America. The cliffs along the shoreline are generally between 30 to 80 feet high, and the country inland of the coal fields is gently rolling in character.      The remains of certain coal seams can be seen in the cliffs along the coast. The majority of these seams dip gently into the sea and so, much of this coal field lies under the ocean. The submarine coal fields of Cape Breton are merely former land coal fields which have been inundated by the sea over the passing centuries. The conversion of the land into submarine coal fields, accelerated by the subsidence of the earth between Newfoundland and Cape Breton, is ongoing. From observations made over a period of 30 years in the late 19th century by Richard Brown at Sydney Mines, it appeared that the conversion of dry into submarine coal field proceeded at a rate of 5 inches per year. At that rate, over 200 feet of the present ocean bed was land coal field when John Cabot landed in North America in 1497.      Of the three main coal fields in Cape Breton: Inverness, Richmond and Sydney, the latter was and still is the most extensively worked and about which most coal history has been written. The Sydney area coal deposits are the most important coal fields in Eastern Canada, the coal field occupies about 500 square kilometres of land in the shape of a parallelogram, extending a distance of about 52 kilometres from Port Morien on the east to the Great Bras d'Or Inlet on the west and then inland for about 10 kilometres. The field is divided by spurs of the East Bay, Coxheath and Boisdale Hills into the Morien, Glace Bay, Sydney Harbour and Bras d'Or Basins, in all of which mining is or has been carried on.      The shape and extent of the submarine portion of the coal field is not precisely known. There are indications that it is roughly oval in shape with its long axis running north easterly. No one knows exactly how far seaward the coal seams extend, but it is safe to say that they continue far beyond the shoreline. The coal beds are remarkably regular in dip and in thickness, so that the chief mining problems of the future will be ventilation and the troubles that arise from pressure at great depths.      Large-scale mining soon exhausted the coal measures in the land area. The workings then proceeded under the sea around 1867 and, by 1941, mining had reached a distance of 2 3/4 miles from shore and a depth of 1,980 feet below sea level. Mining in the submarine portion of the coal field took place mainly in the Harbour Seam at Sydney Mines prior to 1907. Later, entrances were begun at several other points on the south side of Sydney Harbour over a frontage of 15 miles.      Basically, four seams have been worked from the 25 miles of shore frontage extending from the Florence Colliery on the west to Dominion No. 6 Colliery (Donkin) on the east side of the field.      The topmost seam is the Lloyd's Cove Seam. This seam has been worked only near Sydney Mines, where it was followed to a distance of 5,100 feet from the shoreline and to a depth of 500 feet of submarine cover. No work has been carried on at this site since 1923.      Lying below the Lloyd's Cove Seam at a varying distance is the Hub Seam, the topmost seam worked in the Glace Bay - New Waterford area. The high position in the strata column occupied by the Hub Seam and the relatively shallow submarine cover should make it possible to work this seam further seawards and over a wider area than any other seam beneath it, providing it remains workable in thickness and the coal is of good quality.      Below the Hub Seam and separated from it by 300 feet of strata is the Harbour Seam. This seam is remarkably consistent in quality and thickness.      Lying beneath the Harbour Seam, at an average depth of 450 feet is the Phalen Seam, the most extensively mined seam in the Sydney coal field.      The coal of the Sydney Field is of the Bituminous or "soft" variety with little diversity in the quality of the different seams. As compared to other coal, Cape Breton's often contains a greater proportion of combustible material and a smaller proportion of ash; on the other hand, it usually contains a greater amount of sulphur.      The bed of rock between the seams is chiefly made up of shale and slate. They are flexible enough to allow the whole seam to be taken out after the face has advanced far from the shoreline without any fear of a leakage of seawater through the cracks caused by subsidence. The strata dips seaward at an average rate of 6 percent while the ocean bed has a gentle inclination of about 2 percent. Thus, the over burden of rocks on the coal seams increases from the shore line at a rate of about 4 percent. In a few instances there are dips that run as high as 40 percent, but usually the dips in the working places run from 7 percent to 22 percent. The strata are regular and remarkably free of any faults.      Systematic mining has been carried out for over a century, with a peak annual tonnage in 1913 with a figure of 5.75 million tons - a figure not since exceeded. Approximately 300 million long tons of coal have been recovered for sale or for various other uses since coal mining commenced in the Sydney Coal Field.      In 1979, the mining operations of the Sydney Coal Field produced over 2.5 million tons (2 million tonnes) of coal out of a national output of 40 million tons (32.3 million tonnes) or about 6 percent of the total figure. Contrast these figures with those from 1915. In that year, Cape Breton produced 6.2 million short tons of coal or 47 percent of the national total. Today the largest coal-producing province is Alberta - 18 million tons (15 million tonnes) in 1979 - over seven times the figures for Nova Scotia.      Nova Scotia's coal reserves assure a long future for the coal mining industry. The Government of Canada's estimates for the Sydney coal fields show a measured reserve of 238 million tons, an indicated reserve of 622 million tons and a presumed reserve of 557 million tons for a total reserve of 1,357 million tons of coal. Taking into consideration all contingencies that decide annual production market demand, colliery capacity, nature and location of the unworked coal seams - it has been estimated that the recovery time for the projected reserves of the Sydney coal field is in the order of another 200 years of continued mining activity.

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