The Author has been engaged for some time in experiments on the production of useful alloys of nickel and iron, but has hitherto found great difficulty in making these of reliable quality, on account of the marked effect on the properties of the metal of small amounts of impurity. W. H.

Hydraulic Mining in California. By A. J. BOWIE, Jun. (Engineering and Mining Journal of New York, vol. xxiv., pp. 64, 89, 107, 128, 153, 169, 188, 203.)

This Paper, though not in itself a full and clear exposition of the subject, gives information on some points in connection with it supplementary to that contained in the memoir by M. Ed. Sauvage.2

The beds of gold-bearing drift, in California, occur at intervals along the western slope of the Sierra Nevada, from Shasta in the north to Kern County in the south; the most extensive deposits being those in Plumas, Sierra, Placer, and Nevada Counties. The lowest portion of a gravel deposit is, in almost all cases, the richest; thus while the top gravel, in some instances in which it has been worked separately, has yielded gold to the value of only 2 or 3 cents per cubic yard, the bottom gravel from the same deposit has produced frequently $1, $2, or more.

The general mode of opening out and working a hydraulic mine has been described in the abstract of the Paper above mentioned. Particulars are given in the present Paper of the lengths, dimensions, and grades of the tunnels and sluices at different mines, the distribution of the gold in the sluices and undercurrents, the proportion of mercury lost, and the consumption of water.

The water used is measured by the "inch." The value of this varies in different districts; in some it is the amount discharged through an opening 1 inch square, in a 2-inch plank, under a head of 6 inches above the opening. The Smartsville "miner's inch" is measured by a horizontal orifice 4 inches high, with 7 inches head of water above it; thus an opening 250 inches long by 4 inches high, and with a head of 7 inches above the top of the orifice, would discharge 1,000 Smartsville miner's inches of water, each equal to a flow of 1.76 cubic foot per minute, or 2,534 4 cubic feet in twenty-four hours. At the North Bloomfield and La Grange mines, the form of the opening used is different, and the "inch" of water as measured there is equal to a flow of from 1.5 to 1.57 cubic foot per minute.

1 Read before the American Institute of Mining Engineers, in May 1877. This article is reproduced in extenso in Engineering, vol. xxiv., p. 354 et seq.

2 Annales des Mines, vol. ix., p. 1. Vide also Minutes of Proceedings Inst. C.E., vol. xlv., p. 321.

[1877-78. N.S.]

Z

Illustrations are given of the form of nozzle through which the jets of water, 7 to 9 inches in diameter and often under a head of pressure of 300 or 400 feet, are launched against the banks of gravel. The Bowman Dam, now being completed by the North Bloomfield Mining Company, on the head-waters of one of the branches of the Yuba river, is described at some length, and its construction illustrated by several woodcuts. The maximum height of the dam on the lower side is 100 feet, and its extreme length is 425 feet. It rests on a solid granite bed rock, and is constructed chiefly of dry stone-work, faced with heavy walls of dry rubble stones of large size. The slope of the face walls is about 45°. Ribs of cedar, 8 inches thick, are built into the up-stream face walls, and tied back by 3-inch rods 5 feet long. To these ribs a planked skin, of heart sugar pine, in planks 3 inches thick and 8 inches wide, with planed edges, is firmly spiked. This is put on well seasoned, and swells sufficiently to make the face practically watertight, without either battens over the joints or caulking. At the bottom, the plank skin is fitted closely to the bed rock, and caulked with pine wedges. There are three thicknesses of plank (9 inches in all), placed on the lowest 25 feet of the face; two thicknesses (6 inches) on the next 35 feet, and one thickness on the upper 36 feet. It is expected, from experience elsewhere, that this planking will remain sufficiently sound for twenty years, and then it may be readily replaced.

In working hydraulic claims, boulders are frequently met with, which cannot be moved by hand. To facilitate the removal of these, a strong derrick is used. This has frequently a mast 100 feet high, and a boom 92 feet long.. It is kept in position by six guys of galvanised iron wire rope, 11 inch in diameter, which are held by double capstans. The derrick is not taken down when moved; it can be readily shifted 100 feet in ten hours. The hoisting is effected by a "hurdy-gurdy wheel," 12 feet in diameter, worked by a jet of water under pressure. Using 30 inches of water on the wheel (about 45 cubic feet per minute), stones weighing 11 tons may be lifted. Illustrations are given of the wheel and hoisting gear. Similar wheels, up to 18 feet or more in diameter, are used also for other purposes, such as driving stamps; their efficiency is from 0.35 to 0.45 of the theoretical power of the water used.

A table is added, of the total amount of gravel washed in each of fifty-two workings, the gross yield of gold, the yield per cubic yard, and the average height of the banks in which the deposits are worked.

The total cost of "hydraulicking" varies from $0.02 to $0.06 per cubic yard of gravel turned over; the work being done most cheaply where the banks worked are high, the water pressure heavy, and the grade of the sluices moderately steep.

W. H.

Boring by Rope in the United States. By H. ALTHANS.

(Zeitschrift für das Berg-, Hütten- und Salinen-Wesen, vol. xxv., pp. 29-39.)

During the sixteen years ending 1874, 10,499 bore-holes were sunk in the Pennsylvanian oil district, and at the time of the Author's visit these undertakings were being prosecuted with renewed activity, the production of oil increasing notwithstanding the shorter "life" of a well as compared with earlier periods. These bore-holes are often of great depth (over 1,600 feet), and vary from 4 inches to 8 inches in diameter, according to circumstances. Naturally, the execution of such a large amount of similar work has led to a combination of gearing and tools, giving extraordinary results with regard to simplicity and economy; so that, although the apparatus is comparatively of a primitive character, it presents features of interest.

The offtake legs are made of an open framework of 14-inch and 2-inch pine planks, from 60 to 72 feet high, erected on solid oak sill pieces. Behind this erection is placed a 12 to 15-HP. engine, working a belt round a sheave fixed in the middle of a main axle placed in front: this axle (4) feet by 3 inches) has, at its right extremity, a crank for working the boring lever; at the other end is a rope pulley which is connected by an endless rope with the boring rope roll placed on the opposite side of the hole. This roll is 12 feet long and about 13 inches in diameter, with grooved wheels at either end, one of which is acted upon by an iron rod, fixed with staples into the ground, serving as a brake; the other receives the endless rope as above. This rope-an ordinary hempen one, with a hook attachment admitting of proper tension-is employed instead of a belt, as, at the distance of 30 feet between the transmission wheels, it works in the grooves at less tension and at greater velocities without the same tendency to fly off, while it admits of being put in and out of gear with much greater facility. The band pulleys on the engine and main axle are, respectively, 28 inches and 84 inches in diameter, so that at the ordinary speed of the engine (one hundred and twenty strokes) the latter revolves forty times; the rope pulleys on the main axle and roll are 5 feet and 7 feet, the latter thus making twenty-nine revolutions per minute.

The beam for working boring gear (24 feet long by 18 inches wide, 30 inches deep in the middle and 18 inches at each end) is fixed on a strong upright stayed frame, the carriages being fastened to the beam and working on gudgeons placed on the frame. The connection with the crank of the main axle is effected by means of an iron collar loosely hung on the end of the beam, and prevented from shifting by pins on either side; the under side of the collar is reduced to a fork which receives removable pieces of hard wood, and the stroke is variably adjusted to different pin-holes in the crank.

The "reel" for working the sludger or "sand-pump," a wooden axle 8 feet by 8 inches, has, at the end corresponding with the belt pulley of the main axle, a bevel wheel, the gudgeon of which works in an upright lever actuated by a horizontal rod from near the brake wheel of the rope roll where the man in charge is stationed. In one direction the bevel wheel is thus brought in contact with the belt pulley, and in the other it is forced against an upright post serving as a brake; the bevel is to give the necessary angle to the roll for a proper lead, the "reel being entirely to the left-hand side and out of line. This friction wheel being only 2 feet in diameter, the sludger roll makes one hundred and forty revolutions per minute.

The rope, for boring (about 1 inch in diameter) is fixed by means of a screw clamp, hung on the end of a lengthening screw attached to a hook on the end of the beam, and has at the lower end a socket with a box end for the necessary rods. These consist (there being an intermediate "jar piece") of about 46 feet of 33-inch round rods, the lower piece next the chisel having, however, four longitudinal ribs or bosses. The aggregate weight of these rods, including jar piece and chisel, is from 16 to 20 cwt. On account of the uncertain rotation of the chisel (there being no arrangement for uniform rotation), by the twisting or torsion of the rope, it is necessary to "follow down" with a rounder every time, and for this purpose three or four kinds are used, consisting of differently formed bits connected to a segment or segments of a circle, or, as in the case of a "hollow reamer," of a complete circular cut. Of the "fishing tools," one, formed of a simple rod with notched projections, is used for extracting pieces of rope; the others are variously adapted for bringing up broken rods. The sludger is of ordinary construction, with a bottom valve, but it has the peculiarity of being attached to a forked rod, holding at its lower end a bucket, so that in the course of working up and down the latter assists in drawing the silt.

The operation of boring is conducted by four men (two in a shift) working twelve hours. One of these has charge of the boiler and machine, manipulates the sludger, puts the transmission rope in and out of gear, works the brakes for the boring gear, and fixes them with a key when raised to the surface. The other man screws and unscrews the boring rods and chisels, clamps the rope, puts the lever in and out of gear, places the rods aside, attaches a cord to the lever to work the bellows, and sharpens and tempers the tools, and generally keeps all the boring gear in order. The raising of the boring gear and sludger occupies about one minute, and the lowering of the same half a minute in a 300-yard hole; an average advance of 13 yards is made (at a depth of 300 to 500 yards) in twenty-four hours, and a hole 500 yards deep can be put down within thirty-six days. Similar results are attainable in the hard silurian limestones in Canada.

The lining of the holes generally consists of 55-inch tubes, the the box end of these being bell-shaped so as to facilitate the

entrance of the pin end. To make the seating watertight a leaden ring, or seed-bag, is provided on the end of the tubing, but owing to these methods being uncertain, an ingenious "water-packer" is often employed. This consists of a short length of tubing, having at the lower end a small removable flange, in the middle a small boss, below which is a left-winding screw, while the top screws on to the column of tubes. A circular piece of leather with pieces cut out of the circumference, and a hole in the centre so as to pass on to the tube, is put on at the lower end, and the flaps are riveted to a thin iron ring working loosely above the boss. A foot ring provided inside with a left-hand thread (to correspond with the screw in the middle of the tube), and having its outside cut at intervals and bevelled off at the bottom, is then screwed up in the middle of the tube, and holds the leather piece against the boss. The lower flange being then put on, the whole is freely lowered on to the seating; but as soon as the foot-ring reaches the same, the pressure of the water forces the leather against the sides of the hole and downwards in the cuts, and into the underset caused by the bevel of the ring. The object of the left-hand screw is to enable the foot-ring to be released without unscrewing any of the upper joints when it is required to draw the column. When unscrewed, and the column lifted, the foot-ring falls on to the flange.

The cost of a bore-hole 1,641 feet (500 mètres) deep is given :—

appliances} 900 ""

The cost of oil pumps, tanks, and sundry appliances) is given at . The cost of a complete set of boring apparatus, including "fishing tools," is about 790 dollars for a 5-inch to 6-inch hole, and reckoning one-third the value of the plant-boiler, machine, tubing, &c.—the actual cost of boring a 500-yard hole amounts to 6 dollars the mètre, or 8s. 5d. per foot (the dollar being taken at 48. 2d.). Wages are taken at 4 dollars.

The Author describes the class of pumps put in the hole, and concludes by stating that, without entering into comparative advantages of wire and hempen rope for boring, the latter in the water filled hole, appears better adapted for the quick working and heavy blow owing to less drag on change of velocity, and that it possesses the very considerable advantage of winding round small rolls, while the power required is considerably less in deep holes.

A. S.