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 | 2017-03-20T11:41:52+00:00 March 17th, 2017|Categories: Methods|Comments Off on Methods of Mining Metals

Grinding Mill Design & Manufacturing

All 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

CRRK is the common

By | 2017-03-09T13:46:13+00:00 February 20th, 2017|Categories: Crushing & Screening|Comments Off on Grinding Mill Design & Manufacturing

Mining Geology Book

Succession of Minerals and Temperatures of Formation in Ore Deposits of Magmatic Affiliations. The paper presents data accepted by many geochemists and geologists regarding the succession of minerals and the temperatures of formation in ore deposits affiliated with igneous rocks It also presents the individual views of the author on the composition of the solutions that were active and on the mode of deposition He does not regard these views as speculations or hypotheses but as forming a well motivated and consistent theory It is not certain, however, that all investigators will subscribe to them The mining engineer may not always be interested in the field of stability and temperature of origin in the mineralogy of ore deposits, but he certainly is interested in the succession of minerals because this has a definite bearing on the understanding of the ores and on the best processes of extraction The author, therefore, summarizes in plain language the principal features of succession as shown in metallic ores.mining_geology_book

Fissility he considers to be a “structure in rocks by virtue of which they are already separated into parallel laminae.” Fissility may be regarded as a development of the

By | 2017-03-12T03:48:17+00:00 February 13th, 2017|Categories: Geology|Comments Off on Mining Geology Book

Bournonite, Jamesonite, and Calamine Occurences

The results of these investigations show that bournonite (PbCu-SbS3) is present in the ores in greater or less quantity. This fact has never before been reported, as far as can be learned. The failure to recognize this mineral is due to its similarity to tetrahedrite, with which it has probably been confused during a long period of years.

Jamesonite (Pb2Sb2S5) has been reported from the region in a rather doubtful manner, but the writer has seen it in notable amounts from several mines, and can offer the first analysis of this mineral from the district.

Calamine (H2Zn2SiO5) was found at one mine and has never been recognized and reported from the district.

Geography and Geology

Park City, Utah, is located at an elevation of about 7,000 ft. above sea level on the eastern slope of the Wasatch mountains. It is situated approximately 25 miles southeast of Salt Lake City. The geology and ore deposits have been described in detail by Bout well and Woolsey.

The mines visited are situated south-southeast from the town. The Silver King Coalition mine is located in Woodside gulch about 1 mile southeast of Park City, at an altitude of about 8,100 ft. The other mines visited were the

By | 2017-03-24T13:32:40+00:00 March 24th, 2017|Categories: Geology|Tags: |Comments Off on Bournonite, Jamesonite, and Calamine Occurences

Blast Furnace Blowing

Turbo blowers for blast-furnace blowing have now been in use for some years, and a review of the experience gained and the present state of progress may be interesting.

The first blast-furnace blowing engine of this type to be installed in America was built by the General Electric Co. and is installed at the Oxford Furnace of the Empire Iron & Steel Co. This machine was put into operation March 8, 1910. A duplicate unit is situated at the furnace of the Northern Iron Co. at Port Henry, N. Y., which unit was put into operation June 30, 1910 (Fig. 1).

These two units consist of six-stage compressors driven by four-stage Curtis turbines, operating at variable speeds depending on furnace conditions, the maximum speed being 1,950 rev. per minute. The rated volume is 22,500 cu. ft. of actual free air per minute.

Since then, besides these units, there have been built, installed, and put in operation by the General Electric Co., two 25,000 and four 45,000 cu. ft. machines; and by other builders, one 20,000, two 40,000, and one 50,000 cu. ft. machines.

Therefore, the total number of blast-furnace blowing engines of this type on which experience is available is 12.

Besides these, the General

By | 2017-03-24T13:28:27+00:00 March 24th, 2017|Categories: Smelting - Melting - Refining|Tags: |Comments Off on Blast Furnace Blowing

Arsenic Filtration for Potable Use

Before treating for arsenic it’s important to understand both arsenic composition and water chemistry. Arsenic (As) is a natural occurring mineral commonly found in clusters paired with sulfur and other heavy metals i.e.: iron (Fe), manganese (Mn), uranium and hydrogen sulfide (H2S).

Recent studies have shown that temperature variance in arsenic prone areas are known to increase arsenic concentrations. While there isn’t enough research to confirm temperature to arsenic correlation, it’s an important observation.

Health Effects of Arsenic

Arsenic is classified as a toxic element and a known carcinogen, prolonged exposure leads to bioaccumulation directly affecting your kidneys, liver, lungs and skin. Due to arsenic reducing the flow of oxygen in your system it may cause cyanosis which is a discoloration of the fingers and toes due to low oxygen circulation, commonly known as Blue Baby Syndrome which affects newborns and patients with a compromised immune system, if not treated may lead to limb amputations.

There is no easy cure for prolonged arsenic poisoning, by the time symptoms are present the focus is on treating the disease and less on remediating the cause.

arsenic filtration for potable useArsenic in Water

Arsenic in water is commonly

By | 2017-03-24T13:24:45+00:00 March 23rd, 2017|Categories: Uncategorized|Comments Off on Arsenic Filtration for Potable Use

Beach Panning for Gold

One often reads of the rich placer gravels in many of the canoe-traveled rivers of South America. The apparent richness of these gold-bearing gravels impresses the traveler, and in fact he may see batea after batea showing enough colors to figure over a dollar per cubic yard.

These workings are called “playas” from the Spanish word playa, meaning shore or beach. Many workings have been reported in tropical rivers, but to my knowledge no dredge has made a success in such deposits. Investigation generally shows that the area of richness is limited and especially that the depth of the rich concentration is hardly ever more than a few inches.

The Cauca river in Colombia, South America, is noted for its many rich playas. This river rises near Popayan in the southern part of Colombia, flows north through a narrow valley between parallel mountain ranges and empties into the Magdalena river near Maganque. The airline distance between source and mouth of this river is only about 500 miles. The rainfall is large and the lower Cauca appears to be about the size of the Missouri river in the United States. From its mouth up to Valdivia, in the State of Antioqua, it

By | 2017-03-23T16:04:12+00:00 March 23rd, 2017|Categories: Gravity Concentration|Tags: |Comments Off on Beach Panning for Gold

Ammonia Carbon Dioxide Process

Most metallurgists appreciate the great need of a process for the extraction and recovery of valuable metals from complex ore, where the presence of one metal increases the cost of extracting the other metals to such an extent that not any of the metals can be extracted at a profit. We need only refer to some of the mines in Colorado, Utah, and New Mexico, where oxidation has taken place and the sulphur, zinc, copper, and some of the iron and other metals have been leached out, large bodies of oxidized ore remaining, rich in lead, silver, and sometimes gold. These metals have been concentrated by the removal of the other metals, leaving a very desirable ore for treatment in the blast-furnace for the production of lead bullion, and recovery of the silver and gold. If lead is not present, the gold and silver metals are usually recovered by some method of milling, or the ore is shipped to a smelter, where it is mixed with lead ore or copper-iron sulphide ore from some other mine. In these same mines, when developed to greater depth below the leached or oxidized zone, the ore is found to contain the original

By | 2017-03-23T15:57:30+00:00 March 23rd, 2017|Categories: Uncategorized|Tags: |Comments Off on Ammonia Carbon Dioxide Process

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 little finely powdered chalcocite is placed in a test-tube and 2 or 3 cc. of a dilute solution of gold chloride are poured over it, two or three shakes of the tube suffice to remove all the gold from the solution. The color of the solution changes from yellow to pale green, showing that copper is dissolved simultaneously with the precipitation of metallic gold.

If a piece of chalcocite is hung in a dilute aqueous solution of silver sulphate (1/40 normal), a coating of silver begins immediately to form on the mineral, and within a few moments a beautiful silver tree has developed, similar to that formed when metallic zinc is immersed in a similar solution.

When similar experiments are conducted with other sulphides and with certain arsenides and sulph-arsenides, especially those known to be commonly associated with native silver in ore deposits, it is

By | 2017-03-22T15:56:58+00:00 March 22nd, 2017|Categories: Electrometallurgy, Hydrometallurgy|Tags: |Comments Off on Precipitating Gold & Silver Using Metallic Minerals

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 use of the microscope is unquestioned, its utility as an aid in solving mining problems arising during actual every-day mine examination and operation may not be fully appreciated.

Perhaps the most logical method of showing some of these practical applications of the microscope will be to consider first the prospect stage of a mining venture, then the uses to which the instrument may be put during the operation of a working and developed mine, and, finally, to discuss some of the problems of a metallurgical nature that may arise during milling and smelting the ore.

The valuation of mining property as a preliminary to acquiring ownership or determining the advisability of investing time and money in an enterprise is one of the most important and delicate problems that come before the mining engineer. The many and variable factors that have to be taken into account, as, for

By | 2017-03-21T11:17:00+00:00 March 21st, 2017|Categories: Equipment, Mineralogy|Tags: |Comments Off on Microscope in Mining Engineering

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, Villa Grove, being some 20 miles away, it is extremely doubtful whether any considerable amount of ore was ever handled at a profit.

About that time a very capable promoter gathered together a group of these claims and interested some New York people, who had had no previous mining experience, in the purchase of these claims. Following the organization of a company, this promoter became General Manager. As often happens under such conditions, the first step was to erect a mill to treat 100 tons per day. It may not be fair to this enterprise to say that the failure which followed might have been foretold, simply on general principles, but this much is certain—the water supply fluctuates in the course of a season through a wide range and for a considerable portion of the year was inadequate to run this mill at capacity.

By | 2017-03-22T05:22:14+00:00 March 21st, 2017|Categories: Mining|Tags: |Comments Off on Tunnel Construction Cost

Sampling Ore from Hammer Drills

The use of hammer drills for obtaining samples in underground work has increased in recent years. This method has advantages where holes are short, ground conditions preclude the use of diamond drills, satisfactory core recovery is impossible, or sludge samples are accurate enough for the purpose in view. Holes may be drilled at all angles from horizontal to vertical, up or down, but best results usually are obtained with holes drilled above the horizontal. The samples are small sludge samples, and previous statements concerning churn drilling are applicable here. Due to the smaller size of the holes in test drilling, the results of caving may be more pronounced than with churn drilling, especially as test holes seldom are cased.

Test-hole drilling with ordinary hammer drills is employed to check cut, channel, and grab samples or as a substitute therefor and is especially useful for obtaining samples of ground 5 to 20 or 25 feet beyond existing faces, particularly where ore boundaries are gradational or small seams of ore diverge from the main vein for short distances. Longer holes, up to over 250 feet, are drilled with heavy machines, as previously mentioned, as a substitute for diamond drilling where conditions

By | 2017-03-20T11:40:22+00:00 March 20th, 2017|Categories: Geology, Methods|Comments Off on Sampling Ore from Hammer Drills

Drill Core Sampling

The advantages of obtaining core samples that provide a visual record of the rocks and ores sampled and at the same time furnish samples for assay have been pointed out under the caption Exploration by Drilling. The diamond drill, which employs either carbons or bort as cutting media, has been the type of core drill most widely employed in metal mining, largely because it will cut the hardest rocks; it can be used to drill at any angle from horizontal to vertical, up or down.

The shot drill has been used chiefly in obtaining cores of formations at dam sites, testing building foundations and the like, and sampling flat deposits of industrial minerals, where holes drilled vertically downward will provide the desired information. The shot drill has been used extensively together with chum and diamond drills for sampling copper deposits in northern Rhodesia.

With 100-percent core recovery the core will comprise an accurate sample of the ore penetrated. This does not imply that its assay value will be that of the ore at 5 feet or other distance from the hole; and, as with other types of samples, the results are reliable for estimation of ore grades only as cores are

By | 2017-03-20T11:35:07+00:00 March 20th, 2017|Categories: Geology, Methods|Comments Off on Drill Core Sampling