Congress took proper action for the erection of suitable restraining works for the mining debris, hydraulic mining was absolutely prohibited by the courts. Although there was no law against hydraulic mining, nor has there ever been, there was the injunction which did prohibit the dumping of any debris or tailings into the streams. The convention, after a suprisingly harmonious meeting, reached an agreement on the basis of the report of the government commission of engineers and asked Congress to accept and adopt the report of 1891 and take immediate action to put into operation the means suggested.

In March 1893, Congress passed the so-called Caminetti Act which permits the auriferous gravel mines to be operated by the hydraulic system under certain restrictions and conditions. The essential features of the law are that all mines operated under this system shall impound or restrain their debris or tailings, and prevent them from entering the navigable streams, or injuring the lands of persons other than the mine owners. Under the act the California Debris Commission, consisting of three officers of the Corps of Engineers, U.S.A., was appointed by the President. The Commission is empowered to issue licenses fro mining by the hydraulic process under this act when it is satisfied that the debris dams or impounding works are sufficient to restrain the debris. The hydraulic miner must make application to the Commission for license to mine and submit his plans

of the proposed restraining works, which are subject to the approval of the Commission. Each application is advertised for a specified time, and a hearing is held before the Commission at which anyone opposing issuance of a license may state his reasons. When the plans are approved and the necessary works constructed, members of the Commission make a personal examination of the work, and if they are satisfied that the debris can be restrained, a license is issued. Frequent examinations are made to see that the miners are at all times complying with the law; if at any time operators do not comply with the law, the license may be recalled.

Since the passage of the law a number of hydraulic mines have built the works and received permission to mine. The product, however, does not by any means come up to its former dimensions, since the debris must now be run into settling basins behind the restraining dams. Hence, operations are necessarily restricted as compared with those when the amount of gravel washed was limited only by the amount of water available.

It should be remembered that the restrictions do not apply to the hydraulic mines in the drainage basin of the Klamath River, in Trinity and Siskiyou counties, for this is a nonnavigable stream and empties directly into the Pacific Ocean. Furthermore, there are no agricultural lands of importance along the river which might be injured by the

deposition of sands and gravels from the hydraulic mines.

As soon as it became evident that hydraulic mining under the restrictions imposed was practically prohibited, more attention was directed to drift mining and quartz mining. It was not, however, until the inauguration of dredging in the low-lying gravels at the foot of the Sierras, and the subsequent success and development of the method, that production from the placers again began to noticeably affect the annual gold product. For the last 15 years the dredges have consistently contributed between 40 and 50 per cent of the total gold yield of California, and have averaged over 90 per cent of the total annual placer product throughout the period.