Brick-a-Brac Mystery Cache

While traveling along Abraham van Wyk Road you will notice multiple building material producing facilities, notably many producing bricks. 

Clay bricks are made by shaping a plastic mass of clay and water, which is then hardened by drying and firing. Bricks are among the oldest and most enduring of mankind’s building materials. Until comparatively recent times the labour associated with the manufacture of bricks - digging the clay; shaping the bricks and setting the kilns - was done by man or animal. In the last 100 years this process has become highly mechanised - from the clay winning process through to the making and handling of the finished product. 

Modern brick manufacturing facilities are capable of processing at extrusion rates of up to 25 000 bricks per hour. Traditional South African bricks (222 x 106 x 73 mm) weigh 3 to 3,5 kg having lost in the region of 15% of their 'wet weight' during the firing process (at temperatures of 1000° to 1200°C depending on the clay used).

The colour of the finished product is determined by the constituents. Clays containing up to 3% iron oxide give white to cream colours, which change to pinks and reds as the iron oxide content rises to between 8 and 10% - the same constituent in the nearby 'Red Cliffs'. By adding manganese dioxide in proportions from 1 to 4%, a range of grey and brown colours can be produced.

Sadly this industry is not environmentally friendly as evidenced by the accompanying aerial photograph (courtesy Google Earth). One can only hope that the damage is limited to the removal of soil or clay and that the contamination of groundwater is monitored and prevented.

The consumption of such building materials is indicative of progress and development or even prosperity. So we are presented with the challenge of satisfying the appetite for progress balanced against the conservation of the environment...