Geological researches in China, Mongolia, and Japan, during the years 1862-1865.

16 GEOLOGICAL RESEARCHES IN
large, firm pieces formed of well-defined layers, with conchoidal fracture and brilliant metallic lustre.1
Sp. gr....... 1.55
Parts of lead reduced by one part of coal. 33.40
Units of heat...... 682.00
Percentage of ash (gray)....... 4.00
Eight men produce about four tons daily, and the selling price at the mouth of
the mine is $1 70 per ton. A short distance N.W. of the Tatsau is a high cliff of
porphyry, forming part of the edge of the porphyry hills that bound the Chaitang
district on the west. This rock is said, by the Tatsau miners, to cut off the coal
and its accompanying rocks.
The annexed wood-cuts (Figs. 2 and 3) serve to give some idea of the Tatsau mine.
^^ ^ // Z/^"^ Fig. 2' ///f / /~ /,
Fig. 3
l Li Li^^
7/ d
The entrance is by the gallery a, at first horizontal, then rapidly descending to
the inclined shaft b. These are in the smaller and lower seam A drift leads to
the level d, Fig. 3, in the larger seam. In working the coal the miners drive a
level, as far below the surface as the amount of water will permit, and extending
horizontally along the foot wall as far as thexlimits of the mine, with a breadth
equal one-half of the seam when this is less than twenty feet. Beginning at the
end A, they excavate the coal below the gallery, at j, to a depth of from ten to
twenty feet. When this has advanced a short distance they break down from the
1 See Appendix No. 2.