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96

CLAYS

Investigations have been made of some of the clay deposits on Athabaska
river and its tributaries, and of some of the clays and shales along the line
of the Grand Trunk Pacific railway.

In the Athabaska district the clays examined ‘nimediatély overlie the
Devonian limestone or are associated with the McMurray sands. “An excessive
percentage of carbon is noted in the case of certain of the samples examined.
Where the clay lies between the bituminous sand and the Devonian limestone,
this contained carbon has been largely, if not altogether, derived from the
overlying bituminous sand. It is probable that such contamination would
materially decrease on working in from the outcrop.” The depth of the over-
burden, and transportation difficulties are matters for serious consideration.
Results of laboratory tests of some of the more important clays are extracted
from a report published by the Mines Branch, Department of Mines, Canada,
and entitled “Notes on clay deposits near McMurray, Alberta,” by S. ‘C. Ells,

“ Laboratory No. 190. From point on northwest shore of Muskeg river,
between head of portage and mouth of river.

“A light grey, very plastic clay, with good working and drying ao atio
It burns\to a cream-coloured, dense, steel-hard body at cone 3, with a total
shrinkage of 9 per cent, and softens when heated up to a temperature of cone
27. ‘This is a good example of a stoneware clay, and is also a fire-clay. It is the
most refractory clay at present known to occur in the province of Alberta... .

“Taboratory No. 310. This clay requires 23 per cent of water to bring it
to the best working consistency. It is very plastic, and smooth. The drying
must be done slowly after moulding, to avoid cracking. The drying shrinkage
is about 7 per cent. The results obtained in burning are as follows:

Cone Fire shrinkage Absorption Colour
Jo Jo

010 0 10 buff

016 1°4 8 ss

03 3°0 3 ies

Sek: 3°4 re dark puff

5 250 0 grey
15 Fused.

“This is one of the better grades of clay, with good working qualities,
and shrinkages within commercial limits. It would be suitable for the -

‘ manufacture of hard burned fireproofing buff face bricks, or sewer-pipe.

The drying qualities could be improved by the addition of a small per-
centage of ground-burned clay to the raw clay. It must be burned slowly.”
This sample was taken on MacKay river, 11-2 miles from the mouth.

Samples 191, 318, 314, and 317 were taken along Moose river at distances of
3-3, 6-75, 6-7, and 1-8 miles respectively from the mouth. The deposits cre greatly
concealed by slides and talus. —

“ Laboratory No. 191. From Moose river, interbedded between bituminous
sand and Devonian limestone.

“Dark grey, very plastic, smooth, fine-grained clay of the stoneware type.
Burns to a salmon-coloured dense body at cone 3, with rather high shrinkage,

and fuses at cone 18.