The Cumberland Coal fleld of Nova Scotia consists of a basin-shaped strip of coal of carboniferous age stretching from Chignecto Bay in the west where the seams dip under the Bay of Fundy, in a South-Easterly direction to the Town of Springhill, a distance of 25 miles.
The basin is approximately 12 miles wide, lying between the Cobequid Highlands in the North, East and South, and is entirely located in Cumberland County. The coal areas are located mainly in the Joggins River Hebert areas in the North and at Springhill near the Eastern end of the basin; this latter area being the most important in the field.
It is important in delineating the field to note that the Northern and Southern boundaries have not been accurately determined, due to the few rock exposures available, the country being very flat. At the same time, borings conducted at Leamington and other parts of the field indicate considerable geological activity in the Springhill area with several major faults, the principal one being the Aberdeen fault on the South-Eastern fringe of the field and the Fletcher fault on the northern fringe.
The proved workings of the Cumberland Railway and Coal Company also indicate that the seams in the central portion of the basin are beyond workable depth.
A feature of this particular field is the known susceptibility of the workings in the Springhill area to bump, and during the operation of No. 2 Mine a total of 525 bumps were experienced causing substantial losses in life and underground property. The constitution of the surrounding strata and the geological deposition of the original sediments are undoubtedly a vital factor in this susceptibility.
Cores obtained by boring to determine the character of the roof and floor of the seams indicated the presence of very strong sandstones and sandy shales in varying thicknesses overlying and underlying the seams. Some of these bands were up to 80 feet thick. Tests of the cores show that the Springhill shales and sandy shales have a higher strength than in those of most Canadian coal mining districts, and there is no great difference between the strength of the sandstones and of the sandy shales, which are unusually strong.
Plan No. 5 is attached showing the area held under lease by the Cumberland Railway and Coal Company prior to its abandonment of this area.
The coal leases have been surrendered to the Government of Nova Scotia and this Company holds no interest in the field except for some isolated sections of land which are being disposed of as opportunity permits.
The area under lease to the Cumberland Railway and Coal Company during its tenure could be sub-divided as follows:-
Square Miles (I) Area known to be productive, containing seams at reasonable depth 20 (2) Area probably productive and containing seams at reasonable depth 87 (3) Area probably productive, but seams lie at depths over 4,000 feet 31 (4) Area probably unproductive 32 - Total - 170
It should be here noted that the seams in the productive measures have been extensively worked on in No. 2 Mine, before it was closed by a disastrous bump in 1958, the workings had reached a vertical depth of over 4,200 feet from the surface.
A generalized section of the coal measures from the top down and normal thickness of the seam at Springhill is as follows:-
Coal Strata No. 3 Seam 10'0 Strata 280' No. 1 Seam Coal 4'0 Rock 30' Coal 4'0 Strata 70' No. 2 Seam 9'0 Strata 630' No. 7 Seam 4'8 Strata 80' No. 6 Seam 5'6 - Total - 37'2" 1090'
The productive area contained 3.4 per cent of coal, the remainder of the stratigraphical column being made up of shales, sandy shales and strong sandstone bands, up to 80 feet in thickness. The shales and sandy shales vary from soft to extremely hard.
All the seams had been worked prior to the abandonment of leases in the field following the disastrous bump in No. 2 Mine in October 1958. At this time only No. 1 and No. 2 Seams were working.
An explosion in No. 4 Mine in November 1956 caused the closure and abandonment of this mine where Nos. 6 and 7 Seams were worked, at depths of 2600 feet and 3524 feet respectively from the surface.
No. 1 Seam, the first to be mined in the coal field, was in the vicinity of the outcrop and for a distance of 2,000 feet to the dip 8'0" thick. Beyond this point, the seam split into two 4 ft. seams, the upper portion being most extensively worked. The intervening strata between the two leaves of the seam is 30'0" at the 5700 foot level, the limit of the workings in No. 1 Seam, the top seam working having been discontinued in 1951 and the bottom seam in 1954.
No. 3 Seam was mined almost continuously from 1882 until 1916, when the mine was abandoned due to a fire in the pipe slope.
This seam, although normally 10'0" in height, varied greatly in quality and height, splitting into two 4'6" seams in certain areas and turning into shale a short distance to the North and over the entire length of the main slope. When the mine was closed and the workings had reached a depth of 1923 foot and the main slope 4420 feet from the surface.
No. 2 Seam was the most extensively worked in the Springhill area. This seam was worked continuously since No. 2 Mine was opened in 1873 until it closed in 1959.
No. 6 and No. 7 Seams were originally worked as separate collieries with slopes from the surface. In 1933 a cross measure dipping tunnel was driven from the surface to intersect No. 7 Seam. The new slope went into operation as No. 4 Mine in 1934 and No. 6 and No. 7 Collieries were closed in 1934 and 1936 respectively. Thereafter, both seams were worked through No. 4 Slope, No. 6 Seam being reached by short cross measure tunnels from No. 7 Seam main slope.
These tunnels were approximately 300 feet long and avoided the necessity of maintaining expensive haulageways and airways in the separate seams, these roadways being maintained exclusively in No. 7 Seam.
At this time, 1934, both No. 2 Mine and No. 4 Mine were served by a common bankhead, as well as screening and coal washing facilities with each colliery being served by separate hoisting facilities. These two collieries produced approximately 3,000 tons (long) per day.
The coal in all the seams was bituminous and of a fairly friable material. The coal was of a quality suitable for domestic use and possessed good coking qualities. It was a good grade steam coal and found a ready market in the maritime provinces.
The average analysis of the raw coal mined in 1950 is shown below, based on reports Nos. 11, 12, 13, to 14, Department of Mines Branch, Fuel Research Laboratories, 1936.
Colliery Seam B.T.U. F.P.A. Worked F.C. V.M. Sulph. Ash Dry Fahr. 2 2 61.5 30.0 1.18 8.5 13.957 2220 1 58.0 31.3 2.20 10.6 13.407 2060 4 6 54.3 31.9 2.3 13.8 12.470 2100 7 56.8 29.7 1.6 13.5 12.865 2215 Composite 58.44 30.58 1.79 10.98 13.331 2164
A minus 4" + 3/4" coal was passed through the Wash Plant and washed at a specific gravity of 1.6.
The coal measures, where they have been developed to the greatest extent, dip westward at an angle 30 degrees at the outcrop, but this inclination gradually decreases to the dip in the line of the main slope. The average inclination in No. 2 Mine before it closed was about 11 degrees.
To the North and South of the openings of No. 2 and No. 4 Mines the seams pitched steeply, the angle of inclination reaching up to 70 degrees in parts. The field is comparatively free from faults.
To the West of the outcrops boreholes prove that the productive measures continue to dip to the West under rocks of the upper Carboniferous period. At a distance of 2 miles from the outcrop, the rate of the dip has proved to be 17 degrees, which would give a vertical cover of 4100 feet at this point.
No. 2 Slopes, driven 72 degrees Northwest from the outcrop in No. 2 Seam, reached a depth of 4347 feet at 13,400 feet from the surface.
Seven miles west of the outcrop coal seams are found dipping sharply to the east and, although these seams are inferior in quality and thickness to those mined in Springhill and cannot be correlated with them, it is reasonable to assume that they may represent the Springhill Seams on the opposite side of the intervening syncline.
Only part of the Cumberland Coal Field has been proved and very considerable drilling is necessary to determine the remaining resources in the field to depths that can be worked safely without danger of heavy bumps, such as were experienced in No. 2 Seam. It appears to me that neither the Government of Nova Scotia who are the owners of these resources, nor any individual lessee of the coal areas can justifiably take the risk of permitting mining at depths where bumps can constitute a danger to the workmen.
In No. 2 and in No. 3 Mines of the Cumberland Railway and Coal Company, these bumps were first experienced at a depth of 1500 feet of cover.
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Last Modified: 98-02-17
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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