454 W. Rh. Jones—Tin-mining at Ulw Bakau, F.M.S. 
distinguish topaz from quartz they would know the former mineral 
also by a name signifying intimate relationship with cassiterite. 
The rock is phenomenally rich in tin-ore, and typical specimens 
were collected and found to contain 23-9 per cent of cassiterite. The 
extraordinary enrichment occurs at the intersection of two main lodes 
and one subsidiary lode. 
The mine is worked on 55 per cent tribute, with the result that 
only the very rich ‘lode-stuff’ is crushed, and attention is given, 
not to the ultimate economic development of the mine, but to the 
recovery of as much tin-ore as possible before a certain date. 
Granite containing from five to six times the percentage of ore 
profitably worked in Cornwall is at present being thrown on the 
dump-heap, but under the circumstances this is justifiable, and as 
the dump-heap will eventually be worked there is no ultimate waste 
of the country’s mineral resources. Water is very scarce, and the 
rock, after being crushed by foot-stamps, accumulates more rapidly 
than it can be treated. A heavy shower of rain enables the aceumu- 
lation to be washed, and so the work goes on. 
‘« Bibby’s Lode.”’—This mine is also situated at Ulu Bakau, but is 
on the Pahang side of the main watershed. ‘The tin-ore is obtained 
from the undecomposed rock, and it is interesting to note that there 
are distinct differences in its character in different parts of the mine. 
These differences illustrate in a striking and conclusive manner the 
well-known theory of ‘‘ Differentiation of Granite”, and it will be 
helpful for the economic development of the mine to bear in mind 
that the differences in the rock are more apparent than real; that . 
what seems to be a totally different kind of rock is only a modified 
form of its neighbour. The whole of Ulu Bakau and the neighbour- 
hood is formed of granite. and its modifications, viz. pegmatites, 
aplites, quartz veins, and topazized granite or greisen. The latter 
rock is extremely interesting as evidence of great mineralization, for 
the accepted theory of its origin is that it is formed by the action of 
fluoriferous vapours on the felspar of the granite. ‘lhe presence of 
such a fluoride mineral is an indication, not only of mineralization, 
but also of tin-ore, which originally came up as the vapour of tin- 
fluoride. In this particular instance the topazized granite itself 
contains cassiterite. Good washes were obtained from such a rock 
on 4 mining lease about a mile along the path from Ulu Bakau. So 
far no work has been done on this spot. 
Some of the mining engineers who have prospected this property 
have to some extent agreed that the hill has one wide horizontal 
lode running through it and six smaller lodes, also parallel, which 
run through part of the hill. The views they have gathered after 
careful work extending over some months are worthy of serious 
consideration, but the “following observations will, I believe, offer 
another solution to an extremely 1 interesting problem. 
1. A main horizontal lode with other smaller parallel lodes running 
through a considerable hill would be a remarkable occurrence any- 
where; and in a district where faulting and thrusting have occurred 
on a tremendous scale it would be an extraordinary although not 
impossible disposition of the lodes, but in a hill which itself shows 
distinct faulting and thrusting it would be impossible. 
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