Map of the area between Khartoum Quarry and An Meall, Ballachulish, 1944. Khartoum Quarry is three quarters of a mile south of East Laroch. The specimen is of Precambrian, Dalradian age.
The slate has a dark grey colour with an even surface with well-marked grain in places; texture medium. Pyrites ('diamonds') fairly abundant, in diameter generally about 1/8 inch but in some cases up to 1/4 inch. Cleavage-dip is to the north-west at 70 degrees. Bedding-dip is not determined with certainty but appears to be largely coincident with cleavage. There are several joints, along which some movement and local mineralization (formation of pyrites) have taken place, they dip south-south-east at about 15 degrees.
The quarry has the form of an opening with 30 feet walls, and with the entrance at the south-west end, extending along the strike of the cleavage for some 90 yards. It is generally about 16 yds. wide, but has been extended across the strike near the south-east corner for a further 15 to 20 yards. The overburden of clayey moraine is 6 to 12 feet thick; the top rock is bent and broken to a depth of 5 feet.
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