Page images
PDF
EPUB

and other interior States, Dr. David T. assay value of $1,000 per ton in gold and Day, Chief of the Division of Mines of platinum alone, while in other cases it the Geological Survey, established at was demonstrated that, though the sand Portland, Oregon, an experiment station, could not profitably be handled for any where, with an equipment-comprising all single component part, it was well worth the various types of machines that could treatment if arrangements were made to possibly be of use in such work, he and save all the different mineral substances his assistants have been testing the vari- it contained. In other words some deous samples and evolving the best and posits are not rich enough in either gold most practical methods of handling such or platinum to make it pay to work them, material. The experiment station was but, if the magnetite, chromite, garnet, first established early in the summer of monozite and quartz which they yield are 1905 and the work is still actively in also conserved, the net result is to make progress.

the venture a highly profitable one. From the very outset the results were Dr. Day and his assistants have acboth gratifying and surprising. The complished such wonders on the Pacific government investigators not only found Coast that the government has hastened platinum in quantities that exceeded their to broaden the scope of the work and an expectations, but they discovered that the experiment station has been established black sand or sediment was rich in many at Chapel Hill, N. C., for the treatment other valuable substances, notably gold. of the low-grade gold deposits of the In some instances it was evident that a mid-Atlantic and Southern States. Angiven deposit was well worthy of treat other experimental plant or "concentratment merely for the extraction of one or ing pavilion” will be installed at the two minerals, as, for instance, a large coming Jamestown Exposition in order shipment of the sand from Humboldt that the public may be treated to practical County, California, which showed an object lessons regarding the fruitful new

[graphic]

ANOTHER TYPE OF CONCENTRATING MACHINE. FOR HANDLING LOW-GRADE GOLD DEPOSITS.

method of utilizing supposedly useless through a magnetic separator, where the deposits.

magnetic elements are extracted. The process followed in the extraction The concentrators which play so imof the mineral wealth is the same, in the portant a part in this ingenious new case of all deposits of sediment or black method of mining may be popularly desand handled at the government experi- scribed as quivering tables, oblong or cirmental plants. The sand first enters a cular in form, over which there pours "feeder,” after which it is elevated by a perpetually a stream of water. The surbelt conveyor and delivered to a screen. face of the table is covered with grooves Next the material passes to a revolving, or corrugations of rubber or metal. When mixing, distributor, from which it is the gold bearing sand is placed upon a piped to the different concentrators. concentrating table the rush of water This method insures an even quality of carries off the clay and other worthless pulp for all concentrating machines. material while the particles of mineral, After passing over one or another of the being heavier, sink to the bottom and concentrating tables the material for ex- lodge in the riffles. The constant tremamination is placed in a drying furnace, bling of the table serves to concentrate where all the moisture is expelled. The these mineral particles and bring them to pulp, when thoroughly dried, passes a common point of discharge.

Song of the Engine

'LL sing you an engine's song; I am the master of all

Yet I was planned by the hand of man, molded and reared by him.
Tireless, faithful, true, speeding to duty's call,
I bend to my task, let come what may, determined, staunch, and grim.

Mine is a song of pleasure,

For sweet is the wage I earn,
And sweet is the rhythmic measure

Of the wheels my forces turn.

I am the force of the world; its wheels are as children's toys,

For I with my strength can move them all at the touch of a lever bar;
And mine is a monster's strength - there lie my glory and joys-
The strength of my arms is the strength of steel-throbbing, coursing far.

And sweet is the song I sing,

For I sing that man may live,
And sweet is the echoes' ring

That my children's voices give.

Master of man am 1-yet I hark to his every word .

Giving the soul of my life to him in his endless quest for gold ;
Tireless, faithful, true, his command like a soldier heard,
Forever I toil by night or day, till time and the world are old.

· Giving my strength, my life,

To man in his quest for gold;
In the struggle and stress and etrife,
Till time and the world are old.

The MILWAUKEE SENTINEL,

VIEW OF SAN PEDRO BREAKWATER FROM SHORE END. The trestle work off shore for 1900 feet is temporary, built to carry the track of the construction railway.

[graphic]

Creating a New Harbor

By N. A. Bowers

A T San Pedro, thirty miles south

of Los Angeles, California, a great stone breakwater, more

than a mile and a half long, is being built out into the Pacific Ocean. It will cost nearly three millions of dollars—furnished by the national government-and, when it is completed, the only safe and commodious harbor between San Francisco and the Mexican border, a distance of 500 miles, will be ready to handle the great traffic of the rapidly developing Southwest. Already a new transcontinental railroad has made its terminus at Los Angeles and the port of San Pedro is almost certain to become one of the great natural gateways to the Orient, while lumber and other products of the north will be brought to its docks in huge quantities.

San Pedro has long been an important seaport of the Pacific coast; but of late years its steadily growing lumber trade has been seriously hampered by a lack of ample sheltered anchorage. The rapid development of Los Angeles and the adjoining country has created a great demand for lumber; and this lumber, which is obtained chiefly from the Puget Sound

region, can be brought by water far cheaper than by rail. San Pedro had only limited wharfage, and absolutely no sheltered anchorage; but, like many engineering projects of great magnitude, a breakwater was considered impossible or impracticable until it became a necessity.

Congress discovered in this situation a real need for its assistance, and decided to build a government breakwater as the starting point for the making of a great seaport. After long delays, a contract for the construction of the breakwater was letto a Chicago contracting firm. The contract called for a V-shaped structure 8,500 feet long to be built of granite and sandstone. The agreement specified that for the substructure (that part of the structure below low-water line), onethird of the rock must be of a size ranging from 100 to 1,000 lbs.' weight; onethird must weigh between 1,000 and 4,000 lbs.; and the remaining third must be stones of a weight exceeding 4,000 lbs. In the superstructure (that part of the structure above low-water which is set carefully in tiers), no stone could be placed on the harbor side of less than 3

tons' weight; and on the sea side, no $0.84 per ton for the substructure, and stone weighing less than 8 tons. The $3.10 per ton for the superstructure. The contractors agreed to furnish, and to put granite is, however, of a better quality in, the rock of the substructure, for than that used before. It comes by rail $0.541/2 per ton, and that of the super from Casa Blanca, Riverside county, 100 structure for $0.72 per ton.

miles from the site of the breakwater. San Pedro was jubilant over the first At the quarries the rock is loaded on step toward the realization of her hopes; standard flat cars, which are hauled dieveryone knew the details of the contract, rectly out onto the trestle at San Pedro. and the preparations for bringing the Here the heavier pieces are handled by first rock were watched with interest. cranes. The cranes are merely very Buoys were anchored at intervals along large, 90-horse-power steam shovels, with

[graphic][merged small]

the line of the breakwater; and on April 27, 1899, the first barge of rock from Catalina Island, twenty-seven miles to the southwest, made fast to a buoy and dumped its cargo. Things worked well for a time, and soon 80,000 tons had been deposited. Then the contractors were unable to get the rock out as fast as before, and there was trouble ahead. After some parleving, the contract was declared forfeited in March, 1900.

This was, of course, a damper on the bright prospects that had encouraged San Pedro; but in June, 1900, the contract was relet to the California Construction Company, and work on the breakwater was resumed. By the new contract, the Government was charged

specially rigged booms and hoisting tackle substituted for the shovels. The rock for the substructure is swung out over the water, and, when the boom is in the desired position, the stone is released by means of a trip chain. The regular shaped blocks used in the superstructure are carefully placed and fitted.

The building of the superstructure is by far the most interesting feature of the work. A section of the top of the substructure is first brought carefully to the required level (mean low-water mark), and then a monster block of granite weighing from 8 to 25 tons is lifted by the powerful arm of the crane and lowered into place. The stone is first placed in its approximate position to see how it

[graphic][ocr errors][merged small]

fits. If it does not rest quite level or is a trifle too high or low, it is raised again, and the smaller stones of its bed are rearranged. A ponderous block may thus be placed three or four times before it is left in its final position. The elevation of the stringer along the trestle is used as a datum plane, and, by means of a measuring pole lowered from above as each stone is placed, the upper surface of a tier is kept level and regular. The stones of the bottom tier on the sea side can be placed only during calm weather at low

tide. The men must work in one or two feet of water part of the time, and even in the mildest weather they are frequently drenched by a playful wave. Then, too, there is considerable danger from broken chains and falling stones, so that on the whole it is rather difficult to keep a full gang of men. But the present contractors seem to know how to handle these matters, and in spite of many difficulties the breakwater is steadily growing.

As the massive walls of the super

[graphic][merged small]
« PreviousContinue »