The Regal expanding shale deposit is composed of rock of the Upper Cretaceous Cedar District Formation, Nanaimo Group.
Z.D Hora of the provincial Geological Survey reported in 1979 that a large quantity of shale is exposed along the northern bank of the Chemainus River, east of Chipman Creek (Letter by Z.D. Hora, 1979 - Property File). The shale is dark grey and exposed in steep cliffs up to about 70 metres high for about 1 kilometre along the river. The shale beds strike generally east-west, with a dip of between 30 to 40 degrees to the north. At the western end of the exposure, otherwise monotonous, massive looking shale extending over the entire height of the cliff is interrupted in the uppper and lower third by two 5-metre thick layers of banded quartzite. The upper quartzite layer branches and pinches out about halfway to the east end of the exposure. The overall average thickness of the overburden is not likely to exceed a few metres in this area.
Several samples of the shale were taken by Hora in order to test the bloating properties. All samples were fired in an electric kiln to 1090 to 1100 degrees Celsius. This produced uniform looking round-shaped porous particles of a coated nature, with volume expansion estimated at more than 100 per cent. The bloated particles float nicely in water, without soaking and sinking after some time. Hora reports "there are all indications that good quality lightweight aggregate can be produced from this shale" and "a very consevative estimate" of the volume available and accessible for quarrying is "between 2.5 and 5 million cubic metres" (Letter by Z.D. Hora, 1979 - Property File).
Tests done by Shalex Resources Limited in 1986 also indicate that this shale is expandable and suitable as lightweight aggregate for use in the making of light-weight cement. A small quarry is located on the Regal claims, about 300 metres north of the Chemainus River and about 750 metres east of Chipman Creek. At this location, the medium to dark brownish grey shale is soft, friable and thinly laminated, containing minor amounts of siltstone. It was found when crushed and heated to 1220 degrees Celsius that the bulk density changed from approximately 750 kg/cubic metre to 300 kg/cubic metre. The expanded material had a high strength-to-weight ratio, a uniform spherical shape and was not absorbent (Assessment Report 17231, page 18).
