ON Oregon Mountain, in Trinity County, California, is situated the largest active hydraulic gold mine in the world. Covering an area of 2,450 acres, and being the scene of large activities, it is yet secreted among hills and mountains, and is more than fifty miles. from the nearest railroad station, away from the commercial world and the line of travel. The company which owns and works it by hydraulic process. claims it to be the largest and best equipped of all hydraulic mining operations.

Considering the fact that the mine is situated so many miles from the nearest

railroad, and that every piece of the huge machinery and piping now in use had to be conveyed over rough mountainous wagon roads, some portions of which are hardly wide enough to allow a wagon to travel with safety, one must realize what a huge and difficult undertaking it must. have been.

A visit to this mine and an inspection of its equipment and operations would repay the geologist, the engineer, the miner, or even the tourist, if Trinity County did not have within its bounds another single object of interest.

The operations connected with the exploitations of this mine are conducted on a grand scale. To secure the water for these operations a ditch, a flume, tunnel,.

and pipe-line, extending from Oregon Mountain (2,050 feet elevation) to Stewart's Fork (4,170 feet elevation), a distance of twenty-nine miles, had to be constructed.

One of the tunnels on this line of ditch is six by seven feet and 8,940 feet long. This tunnel is at an elevation of nearly 4,000 feet, and required two years to complete, working machine drills from both ends, in many places going through solid rock.

The largest flume is ten miles long and is of semi-hexagonal shape--the better to hug the hill sides-six feet wide on top, two feet on the bottom and four feet deep, with a ten-foot grade per mile. Thus a tremendous pressure is available.

The siphon pipe line crossing Stewart's Fork has a depression of eleven hundred feet at its lowest point. An accompanying photograph will illustrate the difficult engineering that had to be accomplished to make a success of this vast undertaking.

The water thus secured is stored in a reservoir situated on the top of Oregon Mountain. From this reservoir pipe lines are laid direct to the mine. These pipes are of the best grade of iron, varying in thickness from number sixteen to nine, with a diameter of twenty-four to forty-eight inches. The nozzles at the end of each pipe line vary from six to eight inches in diameter, and are constructed with "goose necks" or universal joints,

and can be easily moved by levers or suitable tackle to control the stream.

When an eight-inch nozzle is used, under a head of five hundred feet, 3,000 cubic feet of water are discharged in one minute with a velocity of one hundred and eighty feet per second.

The water as it thus issues from the nozzle feels to the touch like metal, and it retains an unbroken cylindrical form until it strikes the gravel bank at a distance of one hundred and fifty or more feet. Here may be seen a mountain side over five hundred feet in height, gradually dissolving. Very often three or four of these "giants" are directed at one bank, and the resounding impact of water

heavy flow of water conveys the debris and gravel to the amount of about 9,000 cubic yards in every twenty-four hours.

This mine is so situated that the debris from its workings passes into two rivers, both of which are unnavigable streams and hence there is no danger or fear of the injunctions which have prohibited hydraulic mining along the watersheds of the Sacramento River.

Once every three or four weeks the "giants" are stopped, the water is allowed to run out of the sluice boxes, and a general clean up is made, netting from fifteen to forty thousand dollars.

The wonderful power of the stream from one of the giant nozzles in use here can be gauged by the effects which the photographs show. The huge stream works very much faster and more surely than any gang of men, and eliminates from the operations much risk of accident which attends mining by other methods. The operators stand at a distance from the spot where the water does its wonderful work. They control and direct the stream perfectly, however, and the power gathered far back in the mountains tears and cuts and cleaves away the earth with its hidden treasure and then washes it down quietly enough within the reach of the seeker.

It is a wild scene-that at the point of

operations in such a mine-and, indeed, the whole system, clinging as it does upon the mountain sides, furnishes many a sight that is picturesque on its natural side and inspiring as an example of achievement. Engineering problems of magnitude have been solved and difficulties overcome that must have looked like staggering undertakings at the beginning, when the builders first faced their work.