Tin, together with rubber, formed the backbone of the Malayan/Malaysian economy for decades until the late 70s.
In those days, a journey from Butterworth to KL through the Kinta Valley – by train especially – would take us past a number of big open pits which had powerful water jets blasting away at the side slopes and mounds inside. Yellowish muddy water collected at the bottom of these pits forming large pools. Later in our Geography lessons we learned that these were called Gravel Pump mines – and the precious stuff the people were looking for was tin ore.
(the other big time method was the kapal korek, or tin dredge). Those were the ore-some days. Now, many of these mines have been turned into recreational parks.
note : stannum = chemical name for tin