One simply cannot manufacture a good brick without suitable quality clay. De Rijswaard therefore obtains its raw materials solely from quarries containing the finest and purest of clays. Westerwald in Koblenz is one such area, although the washlands of the major Dutch rivers is where we meticulously source the majority of our “soft mud”clay. De Rijswaard deliberately obtains its clay from various sources, with the view to creating a consistent raw material. This also helps us guarantee continuity of colour, shape and size. De Rijswaard processes three base types of clay: Brownish-bronze clay (containing calcium) for the manufacture of yellow bricks, reddish-brown clay (containing iron) for red bricks, and natural clay for a natural-coloured brick body.
The quarried clay is shipped by barge to De Rijswaard’s own purpose built harbour, where it is transhipped to the clay mound. This mound is built up layer by layer. The number of layers of the various clays determines the ultimate composition of each of the clay mixes. This mixture is closely monitored by means of both internal and external test drilling samples. Provided the clay mound complies with established quality requirements, the clay is then cut diagonally through all the layers and transported to the internal mixing hopper.