CO129-451 - Public Offices - 1918 — Page 535

082

:

Memorandum on the Tin Industry in Kokiu

Yunnan. 1914.

531

Introduction.

Kokiu is the largest tinfield in China. The ore is contained mainly in a residual clay formed by de- calcification (more or less superficial) of limestone and can be concentrated by repeated washing. 30 far as

the character of the ore is concerned native methods of

treatment are probably quite effective. These methods, however, have several defects;-

1. Owing to the high altitude, and the cavernous character of the limestone no water is available for washing during the winter and spring seasons so that or e mines in the dry season have to be treated in Summer and autum. The output is therefore directly dependent on the rainfall; and the capital invested during spring and winter can yield no return for eight

or nine months.

2. The quantity of charcoal used in smelting by

the native method is considerable. When the ore is well

dressed the output of metallic tin per day of 24 hours amounts to 1500 cattles for each furnace, over 3000 catties of charcoal being consumed. The total consumption for the whole district exceeds 23,700,000 catties of charcoal per year. The forests within easy reach are

being rapidly exhausted. At the present time the price

of charcoal is about $2.7 per picul, so that for every ton of tin produced the cost of smelting amounts to $200 Hence the cost of production becomes very heavy.

3. The tin thus produced has many impurities and is generally refined in Hongkong. Again each slab of

tin ia different in quality. Owing to the inability to

produce tin of uniform quality, even from the same tap- ping, the metal cannot be directly sold on the foreign

market.

The /