Mineral Processing Engineering

Methods of Mining Metals

This report summarizes mining practices of a large number of metal mines in the United States and foreign countries. The adaptation of mining methods best suited to the various natural conditions in mines is discussed, and comparative costs are presented. The basic data—gathered in the field by Bureau of Mines engineers and consultants in cooperation with mine operators—have been published in a series of information circulars dealing with practices and costs at individual mines and ore-dressing plants. The data have been made comparable by adhering to a standard form of presentation in the individual reports.

The first circular was issued, 250 dealing with mining and milling of metallic ores had been published. Of this number, 164 deal with operations at individual mines and plants—94 with mining only, 59 with milling only, and 11 with mining and milling. Eleven circulars are summaries, each covering a particular mining method, and 53 are discussions of separate operations involved in mine operation or deal with special phases of mining. Seven of them treat special ore-dressing and allied subjects, and 15 arc a part of a mineral-industries survey by counties or districts, in which many individual properties are described and costs and other data are presented. Earlier

By | 2017-04-17T11:24:59+00:00 March 17th, 2017|Categories: Methods|Comments Off on Methods of Mining Metals

Grinding Mill Design & Ball Mill Manufacturer

All Grinding Mill & Ball Mill Manufacturers understand the object of the grinding process is a mechanical reduction in size of crushable material. Grinding can be undertaken in many ways. The most common way for high capacity industrial purposes is to use a tumbling charge of grinding media in a rotating cylinder or drum. The fragmentation of the material in that charge occurs through pressure, impact, and abrasion.

Grinding is converting energy: When the grinding charge is forced to tumble the motor energy is converted into new particle surface and heat.

An important point for the economy is that the size of the grinding media suits the material to be ground.

The choice of mill design depends on the particle size distribution in the feed and in the product wanted. Often the grinding is more economic when executed in a primary step, followed by a secondary step, giving a fine size product.

As experts in crushing and grinding – can offer a full range of grinding mill types and sizes. Our mills are identified by codes of letters:

C=central trunnion discharge
P=peripheral discharge
R=spherical roller trunnion bearing, feed end
H=hydrostatic shoe bearing, feed end
R=spherical roller trunnion bearing, discharge end
K=ring gear and pinion drive


By | 2017-04-28T00:08:53+00:00 February 20th, 2017|Categories: Crushing & Screening|Comments Off on Grinding Mill Design & Ball Mill Manufacturer

SX EW Capital & Operating Cost of Solvent Extraction & Electrowinning

Solution mining followed by solvent extraction-electrowinning (SX-EW) is one possible way to economically extract copper from ore bodies which cannot otherwise be profitably exploited. Published costs for the unit processes of SX and EW are out of date especially in view of the newer reagents now available and the newer circuit configurations. This paper updates the costs for SX-EW and also discusses some of the trade-offs which must be made when designing an SX-EW plant.

The pairing of the unit operations solvent extraction-electrowinning (SX-EW) is an accepted technology for the recovery of high quality copper and it has been used in combination with in situ leaching for copper recovery. The object of this paper is to present the capital and operating costs in 1985 U.S. dollars and other units for the unit operations of SX-EW only so that those companies contemplating the use of this technology for final copper recovery from in situ or solution mining leach liquors will have a good starting point for preliminary cost estimations. Some detailed costs for individual plants have been published but in most cases the information is not current. In addition, a complete survey of all operating plants has not been

By | 2017-04-27T13:42:01+00:00 April 27th, 2017|Categories: Hydrometallurgy|Tags: , , , |Comments Off on SX EW Capital & Operating Cost of Solvent Extraction & Electrowinning

Iron Ore Beneficiation Process

During the last ten years great strides have been made, on the Mesabi range, in the practice of beneficiating low grade iron ore material. By beneficiation is meant all methods of removing impurities, and raising the iron content to a point where it can be sold in open market, the principal impurities being silica and moisture. The general processes to which low grade iron ores are amenable are as follows:


(a) Drying; removes hydroscopic or atmospheric moisture.
(b) Calcining; removes carbon dioxide from iron carbonate, molecular water from hydrated hematites, and atmospheric moisture.
(c) Roasting; removes sulphur, carbon dioxide, molecular water and atmospheric moisture.
(d) Agglomeration; primarily for the purpose of preparing finely divided material for blast furnace; briquetting and sintering.


(a) Screen sizing; removes rock and sand.
(b) Classification; removes sand by means of currents of water of varying velocities.
(c) Log washing; removes fine sand.
(d) Jigging; removes larger particles of impurities than is possible by log washing. Certain types of jigs remove fine sand.
(e) Reciprocating tables; recover fine iron particles from sand discarded by above processes.
(f) Magnetic separation; applicable to the commercial separation of the magnetic oxide of iron from gangue material. From a scientific standpoint it is possible to separate certain hematites and limonites

By | 2017-04-27T10:41:46+00:00 April 27th, 2017|Categories: Steel|Tags: , |Comments Off on Iron Ore Beneficiation Process

Antique Mining Equipment

The early mining of iron ore in Minnesota was carried on with the most primitive kind of tools. The pioneers used only such equipment as could be packed from Duluth through one hundred miles of forest to the first mines on the Vermilion Range and the operations were carried on with picks, shovels, hand drills and wheelbarrows, the ore being hoisted in buckets with a horse winch and carted in horse drawn wagons to the stockpile. This was about the extent of the mechanical Antique Mining Equipment of the Minnesota iron mines in the early eighties.

As soon as a railroad was pushed through from Two Harbors to the Vermilion Range the equipment began to be improved upon; wood burning steam boilers were installed and small steam puffers displaced the horse-winches, wheelbarrows were abandoned and small cars were introduced. Hauling the hoisted ore in wagons was discontinued and trestles were built so that the ore could be stockpiled more cheaply through the use of cars and high piles. These same stockpiles were loaded by hand into the 10 and 15 ton capacity railroad ore cars.

Within a few years a marked change took place—the hand drill gave place to the air drill,

By | 2017-04-27T09:35:24+00:00 April 27th, 2017|Categories: Equipment|Tags: |Comments Off on Antique Mining Equipment

Types of Welding Process

The general object of the investigations has been to extend the use of welding in the construction of merchant ships and, specifically, to provide a definite basis for obtaining the best economy and efficiency in employing welding in place of riveting in the construction of the hulls of such ships.

The extent of the field of application for Fusion Welding and Spot Welding is but little appreciated by engineers other than those who have been directly connected with welding developments. It is evident that this field is an enormous one, including as it does all structures where steel is employed, such as bridges, building structures, tanks of all types and kinds, railway rolling stock, and ships, in addition to numberless miscellaneous applications in industry in general.

However, engineers associated with Welding Research should be on their guard that their enthusiasm over this great field of application shall not lead them into prematurely endorsing the use of Fusion Welding or Spot Welding in constructions where the consequences of failure involve serious menace to life and property, as may often be the case. For example, a particularly important case is that of pressure vessels and especially large high-pressure containers. The success in one hundred

By | 2017-04-27T13:37:12+00:00 April 27th, 2017|Categories: Steel|Tags: |Comments Off on Types of Welding Process

Spectroscopic Determination of Lead in Copper

In a previous article preliminary experiments were described, indicating the possibilities of a quantitative spectroscopic method for the determination of small amounts of lead in copper, which would be accurate and rapid, and could be carried out in the refining plant by one not skilled in chemical analysis. The present paper deals with the development of the method in the factory, giving the details of apparatus and its standardization, and presenting a comparison of the accuracy of the method with that of the standard electrolytic determination. (For variations and other applications of the method, the reader is referred to the first article.)

Outline of Method

A carefully weighed sample (0.4 gm.) of the copper to be tested is placed in a cavity in a graphite positive electrode. An arc capable of regulation is struck, and maintained under constant conditions between the copper sample and a rotating upper carbon electrode. A spectroscope is so adjusted as to observe the lead line (405.8 µµ), as shown in Fig. 1.spectroscopic-lead-copper-steps-in-the-elimination

With a stop-watch, the time is determined between the melting of the copper sample and the disappearance of the lead line from the spectrum. This time

By | 2017-04-26T15:24:10+00:00 April 26th, 2017|Categories: Assaying|Tags: |Comments Off on Spectroscopic Determination of Lead in Copper

Type of Melting Furnace

The following may be said to be essential characteristics of a furnace for determining the melting point of refractories: It should be capable of easily reaching a temperature of 1800° C., since most refractories melt below 1800° C.; for those materials melting over 1800° C., special procedure and technique are usually required. The atmosphere in the furnace should not react chemically with the specimen to any appreciable extent. Facilities should be provided for making temperature measurements with, an optical pyrometer. Good control of the rate of heating should be possible. The type of furnace chosen depends, to some extent, on the original cost, the cost of operation, and the number of melting-point tests to be made.

melting furnace https://www.911metallurgist.com/equipment/smelting/

The two general types of furnaces in use are the electric-resistance furnaces and the fuel-fired furnaces. They may be classified as follows:

Electric Furnaces

Some form of carbon as resistor; such as graphite tube in air, crushed carbon or Kryptol, carbon plate resistor, graphite resistance vacuum furnace. Metal as resistor; such as iridium tube or wire and tungsten or molybdenum wire or tube.

Fuel-fired Furnaces

Coal, coke, or oil, and gas-air or gas-air- oxygen.

Graphite or carbon-tube furnaces, with or

By | 2017-04-26T14:29:34+00:00 April 26th, 2017|Categories: Smelting - Melting - Refining|Comments Off on Type of Melting Furnace

Melting Point of Refractory Materials

The object of this paper is to discuss the factors and conditions that affect the observed values of the melting points of refractory materials and to describe practical methods for the determination of these points. While it appeared to be necessary to discuss some of the general properties of silicates and refractories, these subjects have been entered into only in so far as they relate to the melting point and its determination.

Refractory materials such as fireclays, firebricks, and minerals generally, may be considered to be composed of compounds of metallic oxides, solid solutions of the oxides, the pure oxides, or mixtures of the three classes together with small amounts of a variety of chemical compounds. The oxides of silica and alumina occur most commonly in refractory materials; in combination with these, oxides of the alkali earth, the alkali, the iron group, and the rare earth metals are frequently found.

Meaning of Melting Point

In its strictest sense, the term melting point is applied to the temperature at which the solid and liquid phases of a pure crystalline substance can remain in equilibrium; at the melting point, there is usually a discontinuous change of a number of its physical

By | 2017-04-26T14:27:37+00:00 April 26th, 2017|Categories: Smelting - Melting - Refining|Tags: |Comments Off on Melting Point of Refractory Materials

Manganese Bronze

manganese bronzeDevelopments in engineering during the past decade, particularly as applied to marine construction, mining machinery and other purposes in which corrosion offers a serious problem, have created a large demand for a non-ferrous metal highly resistant to corrosion and at the same time useful in general construction work as a substitute for steel without materially decreasing the factor of safety or increasing the weight of the various parts over that ordinarily used in the case of mild steel.

To obtain the combination of desired properties many compositions have been proposed and used with excellent success, but at the present time probably the most popular and most widely used combination is the non-ferrous alloy commonly called manganese bronze. This is nothing more than a high brass to which have been added, by the proper method of alloying, comparatively small percentages of aluminum, iron, or manganese with the definite purpose in view of strengthening the alloy and rendering it more dense and close-grained than the average yellow-brass casting.
In the manufacture of manganese bronze a great deal has been said about the importance of using only the highest grades of raw material and the beneficial

By | 2017-04-26T11:03:23+00:00 April 26th, 2017|Categories: Smelting - Melting - Refining, Steel|Tags: |Comments Off on Manganese Bronze

Mechanical Properties of Metals

In a recent discussion of Dr. Jeffries’ paper on tungsten, J. C. W. Humfrey, after taking exception to certain of the author’s ideas relative to the cohesion of A and C metal, expresses the opinion that future research is likely to develop a method of preparing tungsten possessing “mechanical properties in line with those of other metals.” The present paper by Dr. Jeffries begins with a determination of comparative properties of tungsten, copper, and iron, in which much dissimilarity is apparent, and ends with a coherent explanation as to why much of this dissimilarity is natural and inevitable, thereby supplying theoretical means for visualizing the changing properties of metals in general, once certain fundamental facts are known.

mechanical properties of metals https://omjena.blogspot.com/2017/02/important-mechanical-properties-of.html

The author’s reasoning is primarily from the standpoint, of the amorphous theory and his principal achievement is the development of an idea of differential cohesion according to conditions of temperature, etc., between A and C metal (which was first plainly suggested by Rosenhain and Ewen, in their papers on Intercrystalline Cohesion of Metals) along with associated ideas, so as to give us a really useful working theory.

I have come rather reluctantly

By | 2017-04-26T09:46:09+00:00 April 26th, 2017|Categories: Pyrometallurgy, Steel|Tags: |Comments Off on Mechanical Properties of Metals

Effect of Oxygen on Precipitation of Metals in Cyanide Solutions

The principle involved in the Crowe vacuum precipitation process is so elementary and the apparatus required is so simple, that the whole subject affords scant material for a technical discussion. As one prominent Colorado metallurgist recently remarked when asked to contribute to this paper: “The Crowe process is the biggest step forward since the early days of the cyanide process, but there is nothing to write about; just put it in your mill and try it.” The writer confesses to a similar feeling, but having been closely identified with the process since its inception in 1916, he is perhaps in a position to at least comment on the theory involved and to record some of the results that have been achieved in actual practise.

In practising the Crowe process, the solutions to be precipitated are first vacuumized in a suitable dispersion tower; that is, thin films of the liquid are subject to the action of a vacuum within a receiver. Substantially all of the dissolved air is thus removed through the vacuum pump, and the treated solution is sent to precipitation without further opportunity for re-absorption of air. The time of contact required is short and the amount of power consumed

By | 2017-04-26T09:42:50+00:00 April 26th, 2017|Categories: Hydrometallurgy|Tags: |Comments Off on Effect of Oxygen on Precipitation of Metals in Cyanide Solutions

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