The Sydney coal field, the largest and most valuable in Nova Scotia, is situated on the north eastern coast of the Island of Cape Breton, extending from Mira Bay on the south to Cape Dauphin on the north, a distance of thirty miles, and has a general dip northeast under the sea. The field embraces the mining communities of Morien, Birch Grove, Reserve, Dominion, Glace Bay, New Waterford, and Sydney Mines. The city of Sydney is situated about midway between the northern and southern extremities of the field and on the western fringe of the productive coal measures.
Sydney Harbour crosses the coal field, cutting off direct rail connection between Sydney Mines and the greater part of the field to the southeast.
The coal measures are exposed in the cliffs on the coast line, which rise to an average height of thirty feet, and are almost continuous throughout the length of the fields.
The portion of the coal field under land forms a small segment of a circle; the greatest distance from the coast landwards is nine miles, and occupies an area of 200 square miles. The greatest distance developed seawards from the shore by mining operations is 3-3/4 miles. The strata maintain a regularity of dip at this distance, proving a submarine area of about 100 square miles. How much further the coal field extends seawards is unknown, but the indications are that it extends far beyond the present economical working limit and in all probability there is a vast submarine coal field.
The productive coal measures are of carboniferous age, these being underlain by beds of sandstone, locally known as the "millstone grit", which defines the southern limit of the coal field, while a spur of syenitic hills cuts off the coal bearing strata on the north.
The coal field is intersected by two main anticlinal folds, having a general course southeast and northwest. The general effect of these folds is to vary the direction and dip of the strata and divide the field into three basins known as the Morien, the Glace Bay and the Lingan-Sydney Mines basins, going from the southeast to the northwest. From the point of view of development, however, the field is divided into four districts, Sydney Harbour cutting through the Lingan-Sydney Mines Basin. The strata dips seawards at the average rate of 6 per cent along the axes of the basins. On both sides of the several basins, the strata have a dip varying from 7 percent to 40 per cent, but generally the rate of the dip in the workings varies from 7 per cent to 25 per cent. The average inclination of the ocean bed is about 2 per cent, so that the overburden of solid measures increases at the rate of 4 percent.
All the seams now being worked give off gas, but they cannot be termed highly gaseous.
The seams in the various basins, in the descending order, are as follows:-
Glace Bay Basin
Sydney Mines Basin
The Blockhouse Seam in the Morien basin is correlated with the Harbour, Victoria and Main Seam of the Glace Bay and Lingan-Sydney Mines basins, respectively. The continuity of the other seams at workable thicknesses is not as persistent throughout the three basins as is the case of the seam mentioned.
Practically the whole of the known Sydney coal field is under lease to the Dominion Coal Company, Ltd. and Nova Scotia Steel & Coal Company, Limited, there being only two or three independent companies operating on a small scale in the Sydney Mines district.
The coal is bituminous. It is of a weak and friable nature and presents difficulties in transportation and handling in this respect. The seams of quality suitable for metallurgical purposes are the Main or Victoria Seam and Lingan Seam in the Lingan-Sydney Mines Basin, the Harbour, Phalen and Emery in the Glace Bay Basin. In the Glace Bay Basin, the sulphur and ash content increases progressively in all the seams east of the anticline which separates the Glace Bay and the Lingan-Sydney Mines Basins, about 30% of the proved area in this basin being suitable for metallurgical purposes. The coals of the seams worked at present coke readily, the Phalen Seam giving the best results in this respect.
The roof overlying the working seams is for the most part shale, which becomes weaker as the mines are developed seawards under greater cover. The roof over the Gardiner and Emery Seams, in limited areas of the Glace Bay Basin, consists of sandstone. The floor ranges from soft fire clay to hard shale. The strata of the productive measures consists of the following:-
The field is remarkably free from strata dislocations or "wants", although in the vicinity of the anticline there are irregular dips and rolls.
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Last Modified: 98-01-05
Authored by: Louis Frost
The information contained on this site is not provided for the purpose of factual
representation. Instead, it is provided in an historical context. Every effort has
been made to ensure that this information represents the actual content of the
original document authored by Louis Frost for the Dominion Coal Company
on or around 1962. Nevertheless, no warranties are provided in any respect.
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