 | Augustus Jesse Bowie - 1878 - 108 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far, experience shows square block riffles to be the best...set with them require steeper grades and more water than those arranged with blocks. As a matter of convenience and economy, block riffles should be used... | |
 | California. Legislature - 1883 - 497 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far, experience shows square block riffles to be the best...objection to their use is the cost of wear and tear. The most economical substitute is rocks, but sluices set with them require steepergrades and more water... | |
 | Augustus Jesse Bowie (Jr.) - 1898 - 360 strani
...the heads of sluices, are : ist. The cross riffle which they make is not excelled by any other form. 2d. Their cheapness under ordinary conditions of timber...character and quantity of the gravel, and the amount ot water. The larger the amount of water (on the same grade) in proportion to that of gravel, the less... | |
 | 1882 - 532 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far. experience shows square block riffles to be the best...objection to their use is the cost of wear and tear. The most economical substitute is rocks, but sluices set with them require steeper grades and more... | |
 | California, California. Legislature - 1883 - 994 strani
...and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far. experience shows square block riffles to be the best...objection to their use is the cost of wear and tear. The most economical substitute is rocks, but sluices set with them require steeper grades and more... | |
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Travels, pp. 77-8. the blocks, and has given excellent results. The block and rock riffles are not desirable for those sluices which have frequently to be cleaned up. So far, experience shows square block riffles to be the best for saving gold. The objection... 