The stamp milling of gold ores; by Rickard T. A. (Thomas Arthur) 1864-

Author:Rickard, T. A. (Thomas Arthur), 1864-
Language: eng
Format: epub
Tags: Ore-dressing, Gold
Publisher: New York, London, The Scientific Publishing co.
Published: 1897-03-25T05:00:00+00:00

An Iron-framed Battery as Erected at Bendlgo.

STAMP HILLINQ OF GOLD ORKB.

and a rock-breaker of such a capacity as would break a Si-hours' supply of ore in 10 hours, leaving the pulley which drives it by day free to operate a dynamo to illuminate the mill by night.

Details of Battery al Bendlgo.

But the economy is not that of labor only ; it extends particularly to wear and tear. Good hand-feeding is more of a day-dream than an actuality ; it is not found at Eendigo, for there the feeding is done badly and irregularly. I have often stood by watching the boys assisting with the blows of a

sledge hammer the entry into the battery of pieces of rock, 4 to 6 inches big, wnich were too large for the feeding hole and which they were too lazy to break up previously. They are not to be blamed so much as the system which makes them possible.

Uneven breaking and irregular feeding add immensely to the wear and tear of the whole mechanism of the mill, A stamp which one moment is falling on soft pulverized particles of ore is at another instant dancing upon a hard, large piece of rock, upon which it descends more than once before breaking it. If the stamp falls full upon it no work may be done, and that is all, save for the jar to the whole machinery; but if it strikes it on the edge a piece of the shoe is in all likelihood chipped off. This can be proved by the actual wear of the shoes, as expressed in ounces of iron abraded per ton of ore crushed. The die is not affected to anything like an equal degree, because the layer of ore upon it acts as a cushion and tends to equalize the wear. Careful inquiry shows that while at the New Chum Consolidated and Pearl mills there are 19.6 and 19.4 ounces, respectively, of the shoe worn away for every ton of ore crushed, at Grass Valley (California), the Black Hills (South Dakota), and Mammoth (Arizona), the wear in no case exceeds 7^ ounces per ton of ore. In spite of the variety of castings, of the varying hardness of ore, and of other changing conditions, the evidence is wonderfully harmonious in accentuating the fact that the use of proper rock-breaking and ore-feeding machines very much decreases the wear and tear of shoes and dies. The time lost in a year by the more frequent stoppage of the work of the stamps in order to replace worn-out shoes with new ones, is by no means inconsiderable and means a monetary loss which must be added to that caused by the excessive waste of the metal of the shoes.

The time of service of the gratings or screens is also seriously diminished by the bad feeding and rough breaking of the ore. So long as man is human there will come times when the feeder, taking a rest or wanting a smoke, will

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