Precipitating Gold & Silver Using Metallic Minerals

While the reducing action of organic matter, of ferrous sulphate, and of hydrogen sulphide has frequently been invoked to account for the deposition of native gold and silver from ore-forming solutions, the high efficiency in this respect of certain of the metallic minerals which form the ore itself has not been sufficiently recognized. If a … Read more

Microscope in Mining Engineering

The valuable results that have followed the application in recent years of microscopic methods of research to problems of ore genesis have been significant, but possibly the recognition of their practical importance is not as general as might be, and while, as a scientific method of investigating ores and rocks, the advantage derived through the … Read more

Tunnel Construction Cost

The Rawley property is located in the Kerber Creek mining-district, Saguache county, Colorado, at an elevation of 10,600 ft. (See sketch-map, Fig. 1.) Ore was found in this vicinity, and claims covering a large area were located and in many instances patented. The ores, however, being of comparatively low grade, and the nearest railway station, … Read more

Pig Iron Manufacturing Process

At the beginning of the use of the electric furnace, for the manufacture of calcium carbide and ferro-alloys, experimental work was conducted in it upon the production of steel from iron ore.  For many years steel and wrought iron have been produced directly from ore on a small scale in the forge, crucible, and reverberatory … Read more

Agitation Leaching in Parral Tank System

Of the treatment of the slime-pulp of gold- and silver-ores by cyanidation, agitation is an essential part. When prepared for treatment, this pulp, consisting of ore reduced to such fineness that approximately 80 per cent, of it will pass through a 200-mesh screen, is mixed with a certain proportion of water, carrying in solution the … Read more

Oil Burning Systems of Liquid Fuels

Oil burners, oil furnaces, and methods of installation, have been the subject of many articles, but information concerning oil-burning systems, based upon scientific principles, is still in great demand, especially in the manufacturing districts of our country. Fuel oil, as it is termed (this being the residuum from oil refineries), has for many years been … Read more

Mining Massive Porphyry Copper Deposits

The past decade has witnessed the development and successful operation of a half dozen or more immense deposits of low-grade copper ore that occur in the Western States. In every case sufficient capital was available to carry out the development of the mines in the manner decided upon, and it is interesting to note the … Read more

Types of Underground Mining Method Comparison

In any discussion of Methods of Underground Mining Comparison, one is repeatedly confronted with the difficulty of dealing with so many variable conditions. It is not an exact science and in the choice of a method each varying factor has a certain weight, which, in many cases, experience alone can determine. In mathematical terms, it is a … Read more

Free and Hindered Settling

In his paper entitled, Development of Hindered-Settling Apparatus, Dr. Richards has related the history of the development of the hindered-settling classifier and given illustrations of the several types of this apparatus which he has designed. An earlier paper, Close Sizing Before Jigging, shows the nature of the hindered-settling phenomenon and the results which it produces. … Read more

Heat Treatment of Steel Castings

In an effort to employ cast steel of a stronger structure than that found in the annealed steel castings, the possibilities of heat treatment which will increase the strength without materially decreasing the ductility may be resorted to. The following abstracted report (which is a brief outline of what has already been done by the … Read more