Lawas Sandstone (2)

Another borehole was drilled about 20m away from the first borehole and it reached 23.5m before encountering bedrock. 

But this bed rock is mainly fresh as compared to highly to moderately weathered generally at the first borehole. It colour is mainly grey which applies to most bedrocks not stained by the surface ground water.

Lawas Sandstone (1)

At the Lawas town near the market, this slightly orangey brown fractured sandstone core was extracted from about 12m below ground level. 
The light orange-brown colour is due to the stain apparently from reddish brown clayey silt deposited at the joints, probably due to water percolation.

Lawas is at the northern region of Sarawak, close to Sabah. It lies on a younger geological formation compared to the Western or Central Sarawak.

Uniaxial Compression Tests and Deformation Measurements of A Sarawak Sedimentary Rock

We often lack of basic data to solve engineering problems such as foundation design on local rocks. We often assume data and properties obtained from foreign publications based on foreign rocks which often are greatly varied from local conditions, and blindly apply in the analysis.  Perhaps, we are lucky because we always apply large safety factors, but problems occasionally did arise, which resulted in great disputes and costs.

This research paper attempts to obtain some basic properties of a local sedimentary rock, Salak South Sandstone, so as to understand the behaviour of the local rock under uniaxial loading conditions.