ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
185 
the outer portion of the bamboo, somewhat similar in shape to the wooden batea. Their 
mesh is such that small particles of mineral matter will not pass through, while the 
water is all drained off. As soon as one pit is finished, generally within eight to ten 
days for a large one, and four to five for a small one; another pit is commenced 
near by. 
( b .) Hmyaudwins. —These, the most numerous of all the classes of mines, are open 
cuttings of an elongated form, the lower ends of which are open to a hill or gully 
side. On commencing this sort of mine some outlay of capital is required, in order 
to bring a supply of water from some adjacent or distant stream, along the mountain 
sides to the head of the working. In one instance one of these gutters is over two 
miles in length. Where a ravine intervenes, the water is conducted across in a 
number of bamboo troughs laid side by side, supported on a bamboo structure, held 
together by strong cross pieces and stays. The water is delivered at the head of the 
cutting through bamboo poles, the ends of which are closed, the water passing through 
an opening in their top which causes it to fall in a more or less scattered manner. 
It flows away through a trench in the bottom of the working, which forms a 
ground sluice. 
The operation of excavating the ruby-bearing portion is performed with long and 
short-handled spuds, and the stuff is thrown in heaps, upon which the falling water 
is directed. As the face of the cutting becomes undermined, the superincumbent 
clay and loam slips down and is washed away. The large stones in it are thrown to 
one side in heaps, or formed into walls to support the refuse, as well as the sides of 
the ground sluice, which is advanced towards the face of the working as the process 
of excavation proceeds. 
When the ruby-bearing material has been sufficiently softened by the falling water, 
the larger stones are picked out and thrown to one side, the remainder being hauled 
with hoes into the upper end of the sluice, where it is puddled. Two or three 
wooden riffles, of two feet or more in height, arrest the sand and gravel containing all 
the minerals. This is taken out, placed in basket bateas and washed clear of the 
remaining clayey particles when it is carefully searched for rubies, spinels, &c. The 
ruby sand which may escape from the upper portion of sluice is collected behind 
riffles placed along its entire length, and washed from time to time ; but the principal 
and valuable portions are procured from the first 12 feet of the sluice head. 
The extensive Rubellite Mines at Nyoungouk (see fig. 12) are worked somewhat on 
the Hmyaudwin principle, the water being delivered by a number of short bamboo 
spouts placed along the top of the face of the cutting, for the purpose of removing 
the top clay and for softening the binding material of the gravel, which contains the 
stones sought for. The work of excavation is very neatly executed, the sides as well 
as the face being made vertical. By dashing water against the exposed face of the 
layer of gravel and sand, with shovel-shaped baskets, the miners are enabled to see 
the rubellites and pick them out by hand. All the produce of these mines is sent to 
MDCCCXCVI.—A. 2 B 
