

GBAVEL MINING: BETWEEN THE SOUTH AND MIDDLE YUBA. 205 



washing, from 1870 to 1874, three and a quarter million cubic yards of top- 

 gravel, made a profit of $ 2,232.84, the yield per cubic yard having been only 

 two and nine tenths cents ; that of the Gold Bun top-gravel having been 

 four and seventy-five hundredths cents. This result led to some investigations 

 in regard to the comparative value of the upper and lower portions of these 

 gravel deposits ; such investigations being considered desirable, in view of the 

 large expenditures contemplated by the company, and, indeed, necessary, in 

 case the lower gravels were to be worked. The following results are quoted 

 from Mr. Smith's report : u To test the comparative values of ground devel- 

 oped by the shaft-workings and top-gravel, two hundred and forty samples, 

 weighing in all two and one-half tons, were taken at even distances from the 

 sides of the drifts, and the same quantity sampled from different layers of the 

 upper bank. These samples were carefully panned out, and yielded, the blue 

 $ 1.10 per ton, the white a large number of colors, but an inconsiderable 

 weight of gold. The gold from the blue dirt w T as from fifty to one hundred 

 times heavier than that from the white gravel." It appears, also, that from 

 every one of the 240 pans one or more colors of gold were obtained.* 



The following general summary of the economical results of hydraulic 

 mining, in the region between the South and Middle Yuba, is extracted from 

 Mr. Hague's Report : — 



" The hydraulic method has now been in use on the ridge for over twenty years, and the expe- 

 rience of this period affords some means of judging of the value of the gravel and the profit in 

 working it. The general results have been very satisfactory. Wherever the richer blue gravel 

 has been accessible, as at the Flats, Badger Hill, and below San Juan, it has, with very rare excep- 

 tions, paid profits, and sometimes large proiits, to its owners. The top-gravel, though much poorer 

 than the blue, has often been found very rich in streaks (due to concentration by surface streams), 

 and lias, in general, paid Luge sums of money to the ditch companies furnishing the water, leavin 

 something besides for the owners of the ground. There are few, if any, trustworthy records of 

 operations showing in detail the costs and proiits or losses of the business in the earlier years of 

 hydraulic mining ; but so far as the top-gravel is considered, the price paid for the water used in 

 mining it is some indication of the result obtained. 



" In early years the price of water was twenty-five cents per inch, for ten hours' flow. This 

 price has fallen, by gradual reductions, to twenty, sixteen and two thirds, twelve and a half, ten, 

 and eight cents per inch, for ten hours, the price at the present time varying from eight to twelve 

 and a half cents per inch for ten hours, or twice that price for twenty-four hours. In many claims 

 in which top-gravel only was washed, the water was paid for at twenty to twenty-five cents per 

 inch for ten hours, and instances are reported in which, after paying these charges, the owners 

 retained handsome profits ; such cases were, however, exceptional. On the other hand, it is well 

 known that under the high rates charged for water in early days, many attempts to wash the top- 

 gravel resulted in loss. 





* Mr. P 



sowie gives 



&s a section of shaft No. 1 in the Malakoff Diggings, in which the number of color* 



obtained at various points beneath the surface is stated. 



