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By B. Fagerberg, P. H. Fahlstrom

Crushing and grinding practice in Sweden follows closely the international pattern. Certain special circumstances, however, have had an influence on its development. Most mines are worked underground. These mines are either quite small or very large. Sulfide ores are commonly treated by custom milling and, apart from the cement industry, the rock species treated are hard and abrasive. Another important factor is the increasingly strict requirements placed on the mechanical condition of different products, especially lump ores and coarse iron-ore concentrates. Increasing requirements are being placed on the concentrate grade to suit the new steel processes. As a result, iron ore beneficiation has expanded considerably for the production of fine pelletizing concentrates. This applies especially to magnetite ores in the intermediate phosphorus range 0.1-1% P. In 1969, about 5.5 million tons of pellets will be manufactured. It should be pointed out, however, that fairly large quantities of coarse products are still being made at mills where the right conditions are available. Crushing and grinding is also of great importance in the production of rich concentrates at high recovery from sulfide ores. In fact, a large part of the development work on the concentration of sulfide ores has been devoted to the crushing and grinding processes. Boliden has played an important role in this connection.

Jan 10, 1969

Ocean environmental factors are an intriguing new set of parameters to be dealt with in the prospecting and exploration phases of resource development for both the continental margins and the deep ocean. While information and data gathering programs for ocean minerals would parallel onshore procedures, their costs generally run higher. Commercial Prospecting-Identification of Mining Sites Two modes of prospecting can be identified-commercia1 prospecting (in which the ultimate objective is to define potential mining sites), and scientific prospecting, which is conducted with different objectives in mind. For ocean exploration, both types of prospecting are carried out prior to the obtaining of any exclusive rights to explore and exploit a specific deposit. Deepsea's John Flipse adds: "Any commercial prospecting program should by its very nature require the freedom to search wherever minerals might occur with maximum flexibility."

Jan 4, 1975

By E. D. Meier

SINCE Dr. St. Albans, in 1840, began to build successful watertube boilers—some of which are still in use—the gravity-return water-tube boiler has been built in many forms, more or less familiar to all who have studied the subject. A single firm in this country published recently a pamphlet, showing some fourteen modifications of their boiler during about as many years. There were hence available to the thoughtful inventor of this latest form many data showing what forms were to be avoided, as well as the effects sure to follow certain erroneous methods of construction in the older types. Improvements in materials, tools, and workmanship made possible, forms formerly prohibited by excessive cost. The first Heine boiler was built by A. Borsig & Co., for the

Jan 1, 1886

Since the beginning of the 20th century the world has been trying to find a new political system, even as it did at the end of the 18th century. The French Revolution instigated the destruction of absolute monarchies when Napoleon unwittingly showed the masses the advantages of freedom, as opposed to the abuses of unlimited power by the imperialists. In spite of advances in culture, science, and technology during the past 50 years, there is a hangover of laissez-faire economic principles. Failure to divert the trends of minority pressure groups has caused two world wars and is the basis for the current social unrest and turmoil. In the ebullition of ideas there have risen to the surface the dregs of ideas, old and new-Nazism, Fascism, Russian Communism-a hodgepodge of imperialistic, socialistic, communistic and capitalistic maneuverings where state monopoly of capital enables ruthless exploitation of the masses. The United States owes much of its industrial greatness to the work of pioneers in the mineral industries. The task of the pioneer was to locate and develop in a rude way the mineral resources of the nation. Today, mineral industries leaders are still in great demand, but for a different purpose-to direct intelligent utilization of the limited, waning, submarginal mineral resources. Today the need is for trained earth scientists, mineral

Jan 1, 1950

By R. V. Ramani, R. Stefanko, P. C. Thakur

The effects of diesel exhaust on mine ventilation systems are discussed. Mathematical models for emission of gaseous pollutants from diesel engines and their dispersion into mine air have been developed. Situations likely to prevail in mines were originally modeled using partial differential equations, but only simplified solutions are presented here. Validity of these models has been established by field observation of the growth of carbon monoxide concentrations in mine air environment. Consequently, these models can be used for air requirement calculations for diesel engines in underground mines.

Jan 1, 1977

By Thomas M. Drown

Theodore Dehon Rand was appointed Treasurer of the American Institute of Mining Engineers by the Council, at the Boston meeting of February, 1873, to fill a vacancy caused by the resignation of the treasurer who had been elected at the first meeting in Wilkes-Barre in May, 1871. He was elected by the Institute to this offce in the following May, and yearly thereafter until 1903. He often alluded with amusement to the abrupt way in which he was injected into this position, by my coming to his office and asking him to accept the appointment as Treasurer, on the ground that he was eminently fitted for the position by reason of his legal and business knowledge, his interest in geology and mineralogy, and more particularly because he was a neighbor of the person (to wit, myself) who was slated for the Secretaryship, and they could thus convenient.ly confer on Institute matters. He consented, on condition that the duties should not involve too.much additional work for him. This assurance was easily given, for the Institute then

Jan 1, 1904

By S. Mellgren, W. Opie

AN equilibrium state of importance in the process of electrolytically depositing titanium from fused chloride electrolytes is that which exists between titanium metal, titanium dichloride, and titanium trichloride. This can be expressed by the reaction titanium concentration of the solution, temperature, and the proportion of strontium chloride and sodium chloride in the solution. Procedure The general procedure used consisted of the following steps: 1) Development of an analytical method for determining Ti+2 and total titanium. 2) Preparation of batches of fused salt solutions containing various amounts of total titanium, Ti+2 and Ti+3 3) Blending of the prepared batches and excess titanium metal in Vycor tubes and allowing the solutions to come to equilibrium. By blending, solutions with different total titanium content could be prepared and equilibrium could be approached from the high Ti+2 and low Ti+2 sides. 4) Studying the effect of titanium concentration, temperature, and the mole ratio of the solvent chlorides, SrC1, and NaC1, upon the equilibrium.

Jan 1, 1958

J. J. RUTLEDGE,* McAlester, Okla. (written discussiont).-Research work has often a more immediate and practical application to the in-dustries than even the investigators themselves realize, but coal mining has not attracted the investigator, except in so far as the mine-accident prevention work and fuel investigations are concerned. In future, the coal geologist will study the subsurface geology of the various coal seams as the petroleum geologist now studies the oil sands, and from the results of these studies the coal operator will be able to locate his shafts to the best possible advantage and to avoid faults that would interfere with underground work. There would have been many thousands of dollars saved, and perhaps some reputations, if a good stratigrapher. had been called into consultation in the southern part of Somerset County, Pa., where a local seam of coal, quite thick, was mistaken for the Pittsburgh seam, which, if ever present at that point, had long since been eroded. Why will the Quemanhoming coal carry more sulfur without injuring the grate bars than George's Creek Big Vein? Only the investigator can answer and yet the fact that the above is true means a greater price for the thinner coal. The owner of the land in Oklahoma receives one-fourth of the cotton crop produced by the tenant who farms his land and one-third of the

Jan 11, 1919

By Richmond Bennett

Airborne geochemistry became a reality with the advent of a high-sensitivity air¬borne gamma ray spectrometer with large volume NAI(Tl) crystal detectors. The high-sensitivity spectrometer measures small variations in the concentration of potassium (as Ks°), thorium (as Tl308) and uranium (as Bi.214) along the flight lines in the area surveyed. Hydrothermal dispersion patterns are indicated by anomalous measured values of the concentrations of potassium, thorium, uranium, or their ratios. In two recent Australian survey areas, copper mineralization was located along favorable structures within hydrothermal dispersion patterns delineated by airborne geochemical surveys. In metamorphic terrane where there had been po¬tassium metasomatism, the hydrothermal dispersion patterns were indicated by high potassium/uranium ratios (K40/Bi). In a sedimentary environment that had been intruded by a stock, the path of hydrothermal fluids was indicated by uranium (Bi214), thorium (TV'), and uranium/ thorium (Bi214/Tl208) ratios.

Jan 1, 1972

By Brij M. Moudgil, John P. Bunch

During hydraulic processing of phosphate matrix enormous amounts of phosphate slimes are produced. Significant portions of mined land are utilized to store the slimes. Some dewatering of the slimes is essential before any reclamation of the storage ponds can be undertaken. Dewatering and reclamation of slimes storage ponds pose many problems which are not encountered in reclamation of other mined areas.

Jan 1, 1977

Freeport's Floating Mine Begins Sulphur Operation Eight years of research were culminated when Freeport Sulphur Co.'s floating mine plant went into operation on Bay Ste. Elaine in the remote Louisiana bayou country 60 miles southwest of New Orleans.

Jan 1, 1953

INTERNAL The year 1976 was another outstanding year in the operation of the Institute and in the success of its varied activities. Total AIME membership reached 59,773 for a gain of. 6.4 percent. Total revenue increased to $5,111,2 10, up 22.4 percent, and balance sheet assets increased to $8,479,612, up 12.2 percent from the previous year. AIME and its constituent units conducted 30 technical meetings during the year, and attendance was up at most of them. Publications issued by the Constituent Societies continued a healthy growth. During the year 9 new local Sections were established, and at the end of the year the Institute had 150 Sections, with 19 of them overseas. Details on all of these operations are on pages 2 and 3 of this report.

Jan 4, 1977

By Howard W. Miller, Charles R. L. Oder

APPROXIMATELY 5000 tons of zinc ore a day was mined during 1943 in the Mascot-Jefferson City district in East Tennessee. This ore came from the Kingsport formation, a part of the Knox dolomite, of Ordovician age. The Kingsport is composed of 350 to 400 ft. of limestone and dolomite. Thin cherts, sandy layers and shales are numerous. Frequently, the limestones are altered to crystalline dolomite. The Kingsport is divisible into four main lithologic zones. These divisions are illustrated in an accompanying table, which gives detailed sections of the ore-bearing beds as found in the mines and shows the exact positions of the various ore zones within the formation. Key beds are described and the practical applications of stratigraphy in mapping, prospecting and mining are discussed.

Jan 1, 1945

By Yoshinao Nakada

In many experiments involving electropolishing such as electropolishing during deformation and electrothinning of deformed metals for electron microscopy, it is usually assumed that the specimen temperature is the same as the temperature of the polishing bath. In order to test this assumption, the interior temperature of aluminum single and polycrystals was measured while they were being electropolished. Specimens were 1/4 by 1/4 by 6 in. and were of 99.99 pct purity. A small hole 1 in. deep was drilled axially at one end of the specimen so that a copper-constantan thermocouple could be inserted. The electropolishing solution was 4 parts methanol (reagent grade) and 1 part perchloric acid (70 pct). The electropolishing was performed using an apparatus shown in Fig. 1. The electropolishing solution was stirred by a motor-driven stirrer and was cooled to —5°C with a mixture of methanol and dry ice. Electrolyte temperature was measured and remained at -5°C during the electropolishing. Current density of 0.3 amp per sq. cm was used. When the current was turned on, after about a 5-sec delay, the temperature began to rise rapidly until it reached 65°C. In order to determine whether the temperature measured was localized, the thermal expansion of the specimen was meas-

Jan 1, 1965

By Lawrence Adler

The authors are to be complimented on using a novel and potentially helpful technique to analyze the effects of mine roof trusses. However, some criticisms of their application and analysis seem appropriate to further its acceptance. This discussion will deal with the normal structural analysis format covering: 1) material. 2) load, 3) structure, and 4) analysis. It will then briefly review the testing procedures and finally cover miscellaneous items. That the analytical and testing results admittedly disagreed by several orders of magnitude, indicates a need for improved understanding. The introduction of data determined previously was not assisted by references to "Interim" or "Preliminary" reports. This material should have been concisely reformulated for the open discussions that Transactions encourage. In addition, many important simplifying assumptions are tacitly made without recognition, and much less, an attempted justification.

Jan 1, 1979

By Ralph Arnold

PERHAPS the most striking feature in the three newly discovered fields in the Los Angeles basin is the enormous thickness of oil sand. The total thickness is not yet known in any of the fields, since no well has as yet been drilled deep enough to pass through it. In the Signal Hill area a maximum of 1500 ft. or more of productive sand has been penetrated. In the other fields the interbedding of considerable shale members renders the total sand thickness somewhat less, but in all cases the depth of sand strata is enormous when compared with other California fields. For instance, in the Coalinga field the total thickness of sand on the average has been less than 100 ft., while in the Midway and Sunset fields not more than 250 ft. of actual productive sand has been encountered in any one place. This condition has so upset all previous ideas regard-ing the possible future production that but few of the engineers who have had to deal with the situation feel

Jan 5, 1923

By R. B. Haagensen, E. Martinez, V. Kudryk

The sample under investigation contained approximately 16% BaSO, and was 80% -325 mesh. Established methods for floating barite did not produce concentrates of satisfactory grade or barite recovery because of low barite content and the presence of 6% calcite in the feed. By using a new long-chain sulfosuccinamate collector in combination with relatively high concentrations of sodium silicate, a barite concentrate was produced that would be acceptable as an oil-drilling mud using a simple rougher-cleaner circuit. No desliming of the fine-ground feed was necessary. Barite recovery was over 80% and the concentrate produced had a specific gravity higher than 4.3. During the course of the investigation, a procedure was developed to obtain semiquantitative determinations of barite, calcite, quartz, and feldspar in test samples using an infrared spectrophotometer. Samples were also analyzed in a thermobalance for determination of the calcite content. The use of these instruments made it possible to obtain quick mineralogical assays and proved to be of invaluable assistance in guiding the flotation testing.

Jan 1, 1976

By C. C. Hatch, A. L. Mular

The methodology employed to develop a digital simulation of the Brenda Mines Ltd., Peachland, B. C., secondary crushing plant is described. Methodology includes data acquisition, data adjustment, model building, and the construction of a simulator structure. The simulator was utilized to study the effects of secondary and tertiary crusher close side settings, secondary screen opening, plant feed rate, and percent + 1 in. in the feed on the following responses: percent - 1/2 in. in the final product, plant reduction ratio, circulating load ratio, and screen efficiency. Results are presented in graphical form.

Jan 1, 1983

By W. J. Travers

SEVERAL new procedures for completing oil wells have been developed in recent years. Each method when used where properly applicable promises to be a definite aid to operators in lowering development or operating costs, or in developing the full potentialities of the oil well. Multiple-zone completions are now frequently used, in contrast to the older practice of setting a solid water string over each zone to be produced. Gravel packing in unconsolidated formations often prevents sand troubles formerly experienced where a conventional perforated liner was used. Light-weight bentonitic clay muds and oil-base drilling fluids are definite steps toward eliminating mudding damage, which occurs when heavy rotary mud is used. Since in each case the new procedure developed is an alternate of older conventional methods, a problem of selection is presented. The purpose of this paper is to suggest methods of arriving at these choices and to present practical observations that may be of aid in their application.

Jan 1, 1942

By Roger G. Rowe

In late 1980, Exxon Minerals Company performed rock mechanics testing on oriented 150 mm drill core from their 75Fi tonne massive sulfide deposit near Crandon, Wisconsin. Instrumented samples from depths of 300 meters indicate premining horizontal stresses in a north-south direction (parallel to pillar faces) to average 12,300 kPa, with the perpendicular plane yielding an average stress of 14,630 kPa. Rock strength versus sample size was compared using uniaxial compressive strengths from 47 mm, 95 mm and 150 mm core. Massive sulfide averaged 153,300 kPa, 139,845 kPa and 75,330 kPa respectively, while the hanging wall and foot- wall averaged 92,000 kPa, 76,560 kPa and 57,960 kPa respectively. Point load compressive strengths were calculated using formula suggested by both Hassani et al., 1980 and Broch et al., 1972. Values calculated using the Hassani formula closely resembled pre- existing point load and uniaxial compressive strengths, while values calculated using the Broch formula were 50 percent low.

Jan 1, 1982