From a very reliable source. ;-) Alluvial is much easier to...

From a very reliable source. ;-)

Alluvial is much easier to process that hard rock, just a simple gravity plant because it is already free from its host rock and been deposited in the river from years of erosion. Sounds like most dredges concentrate the ore on board or pump to a plant next to it, and process to a high grade concentrate (without the need for grinding).

The main method of mining large placer tin deposits is by bucket-line dredging. The alluvium containing the tin is excavated and transported by a continuous chain of buckets to the interior of the dredge where it is washed and roughly concentrated. In South-East Asia particularly, smaller deposits, or those unsuitable for dredging (e.g. because the bedrock is very rough) are worked by gravel pumping. The alluvium is broken up by a high pressure jet of water and the resulting slurry is pumped to the concentrating plant.

The impure cassiterite concentrate is further concentrated by gravity methods which involve passing the concentrate in a stream of water over equipment such as jigs, spirals, or shaking tables. This separates the heavy cassiterite from the lighter minerals such as quartz. Magnetic or electrostatic separation removes the heavy mineral impurities. The end product is a cassiterite concentrate containing about 70% tin.

See extract below from Aus Gov site:
http://www.australianminesatlas.gov.au/education/fact_sheets/tin.html

Enjoy.

;-)

Another update we wait for is about the batch. The story is growing so fast I'm starting to lose track of everything planned.