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By R. M. Wilhelm

HIGH-TEMPERATURE thermometry,, as treated in this paper, deals with the measurement of temperature in the range 100° to 550° C. The lower limit corresponds to the temperature of boiling water at normal atmospheric pressure, the upper limit is approximately the highest temperature to which mercury in a glass thermometer may be safely subjected.1 In this range., the domains of pyrometry and thermometry overlap somewhat, for high-temperature resistance thermometers and thermocouples generally classed as pyrometers are often used below 550° C. This paper will be confined to high-temperature mercurial thermometers, and indicating and recording thermometers of the vapor pressure, liquid or gas filled, and bimetallic or graphite-metal expansion types, a classification of which is as follows: CLASSIFICATION OF THERMOMETERS GENERAL CLASSIFICATION SUBDIVISIONS Mercury in glass Laboratory- Etched or engraved stems (mercurial) Enclosed scale (Einschlus) Industrial Vapor pressure Indicating and Pressure Liquid filled recording Gas filled Bimetallic Graphite-metal expansion

Jan 9, 1919

By Robert F. Hauck

This chapter discusses a new technology for computer control in open-pit mine operations: the real time automatic dispatching of manually driven trucks to shovels. The monitoring of truck activity is accomplished by detection of local radio signals. Computer-operated directives are communicated to drivers by remote controlled digital display units inside the truck cab. The production objective is to maximize tonnage in a cost effective manner. The problem is formulated in the appendix and the solution method is briefly described. Side conditions such as maintaining delivered ore grade aims, balancing waste to ore volumes to keep within stripping ratio tolerances, and meeting production rate requirements temporarily established for certain shovels are also discussed. Experience with a developed event- to-event simulator applied to analyses of several North American mining operations using this technique is summarized. Complete systems employing this technology are now under- going installation at mine sites in Canada and the United States.

Jan 1, 1979

By John A. Gisby

Phase equilibria for multi-component systems can be calculated reliably from critically assessed thermodynamic data for sub-systems using software packages like MTDATA, developed by the National Physical Laboratory, UK (NPL). Models and data resulting from an ongoing Mineral Industry Research Organisation (MIRO) project make such calculations possible for the complex systems encountered during sulphide smelting, involving interactions between matte, slag, metal, and gas phases. Predictive calculations can be made that are directly relevant to industrial processes, covering composition and temperature ranges beyond the scope of hard- copy phase diagram compilations, allowing the feasibility of more economic and environmentally sound routes to be explored, better choice of materials to be made, and pilot plant studies to ,be directed more efficiently. Current applications include the selection of suitable fluxing practices in copper and nickel smelting, analysing the operation of the Kennecott copper smelter, optimising the recovery of precious metals and investigating refractory wear.

Jan 1, 2002

By P. J. Suardini, S. K. Kawatra

A number of on-stream coal slurry analyzers are presently being developed and commercialized for measuring ash and solids in coal process streams, particularly around flotation circuits. The eventual goal of these efforts is to develop on-line quality control systems for flotation circuits and other fine-coal cleaning operations. As part of this on-line monitoring and control effort, it is important to gain a better understanding of the response of industrial flotation circuits to changing operating conditions. This paper summarizes the results from a detailed sampling program performed at an industrial coal flotation circuit in western Pennsylvania. The testing focused on evaluating the response of the circuit to changes in reagent dosages, operating conditions and feed compositions. The testing indicated that it is desirable to maintain high collector-to-frother ratios to enhance coarse particle flotation. The recovery of fine impurity particles was also proportional to water recovery, due to hydraulic entrainment. Key words: Industrial, Coal, Flotation, Circuit, Reagent, Response.

Jan 1, 1995

By Robert E. Delavault, Harry V. Warren

Geochemistry in all its branches is playing G an increasingly important part in the business of mine finding. Although geochemical studies were commenced more than 50 years ago, interest in this subject did not become widespread until the late 1930's when in Scandinavia and the U.S.S.R. a whole series of investigations were initiated. Unfortunately for those in North America, the results of these investigations have only recently become available. In Canada and the U.S. geochemistry as a serious mine finding tool dates back only to the period following World War II. This article deals primarily with soils, which have found widespread acceptance as a useful tool in geochemical prospecting. Actually soils vary greatly in texture, structure, profile, and mineral background. Soil sampling poses no hardship for normal intellects, but it does assume an elementary knowledge of soil science and of the chemical problems involved in determining the absolute and relative amounts of a particular element in any particular soil.

Oct 1, 1956

By Robert G. Woolery, S. Ramachandran, James A. Weber, Donald J. Hansen

Union Carbide began looking seriously at heap leaching in 1971. At that time some 1.6 million tons of mineral averaging 0.40 kg U308 /t) (0.80 lb U308) were stockpiled at various sites around the Gas Hills, Wyoming, uranium facility. Several alternatives for economically exploiting these reserves were considered and heap leaching seemed the most attractive. At the time, Western Nuclear Inc. was operating a heap leaching project nearby in which the low-grade ore was leached with sulfuric acid, the product liquor treated in an on site solvent extraction circuit, and the stripped product liquor re-acidified and recycled. The operators were most generous in allowing us to visit their site and in answering our questions. They were also helpful in discussing the problems associated with heap leaching. Their experience confirmed our belief that it was possible to operate a heap leach profitably on material too low grade for conventional milling.

Jan 3, 1978

A new $18-million hydrometallurgical ore treatment facility for the recovery of molybdenum oxide was dedicated at Climax, Colo., on November 19 by Climax Molybdenum Co., division of AMAX. The Company has been producing molybdenum from molybdenite (MoS2) ores since 1918. Now oxide values, formerly lost in the sulfide flotation plant tailing are to be processed to yield about 3 million Ib per year of metal. In 1965, Climax produced about 50% of world molybdenum from sulfide ore. This ore is mined at the rate of 42,000 tpd. The annual production of concentrate is 100 million lb containing 90% to 92% MoS2, or about 50 million lb of metal. As only a relatively small portion of the total Climax production is sufficiently enriched in oxide molybdenum to process through the new plant, 5700 tpd of selected ore containing 1.5 lb of Mo per ton is now treated by the new process.

Jan 12, 1966

By S. F. Willey

Difficulties encountered in justifying replacements for overage mobile mine equipment at the Gay mine are common to most mining operations. More critical management reviews, resulting from ever rising capital expenses, increased such difficulties. These increased difficulties are especially apparent to those who are primarily operators and are not statisticians, mathematicians or computer men. The Gay mine is located 17 mi east of the town of Fort Hall in southern Idaho. This open pit operation annually supplies the J. R. Simplot Co. and the FMC Corp. with 1.5-2.0 million tons of phosphate ore. Stripping ratios average approximately three bank cubic yards of waste per ton of ore mined. The mobile mine equipment fleet consists of ten 24-cu yd scrapers; twenty-one 30-50-ton end-dump trucks; four 3%-4%- cu yd shovels; fifteen dozers in the D-8 and D-9 classes; and three road patrols. Equipment replacement is based on the results of evaluations made on individual units.

Jan 9, 1972

By Ross W. Smith, Nikhil Trivedi

The variation of point of zero charge (PZC) of both simple and complex oxide minerals was studied as a function of aging time in water. In most cases the PZC's of the simple oxides moved toward more basic pH values with aging time. Evidence to date suggests that this phenomenon relates to dissolution of disturbed layers on the mineral's surface accompanied by later readsorption of metal hydroxy species back onto these surfaces. The readsorption takes place after the solution becomes supersaturated with respect to some crystalline phase. The variation of PZC's of complex oxides as a function of aging time in water is apparently related to several different mechanisms. In a few cases PZC shifted toward more basic values with time. This shift could be attributed to much the same mechanism as for simple oxides. In most cases, however, PZC of complex oxides shifted toward more acid values with aging time, probably because of loss to solution of soluble cations whose oxides possess basic PZC's.

Jan 1, 1975

By T. H. Janes

NATURAL abrasives of some type are found in all countries of the world. In order of their hardness the principal natural abrasives are diamond, corundum, emery, and garnet, which are termed high grade, and the various forms of silica, including pumice, pumicite, ground feldspar, china clay and, most important, sandstone. The properties qualifying materials for use as abrasives are hardness, toughness, grain shape and size, character of fracture, and purity or uniformity. For manufacture of bonded grain abrasives such as grinding wheels, the stability of the abrasive and its bonding characteristics are also important. No single property is paramount for all uses. Extreme hardness and toughness are needed for some applications, as in diamonds for drill bits, while for other purposes the capacity of the abrasive to break down slowly under use and to develop fresh cutting edges is of greatest importance, as with garnet for sandpaper. In dentifrices, soaps, and metal polishes, of course, hardness and toughness are objectionable.

Jan 10, 1954

By Dr. Egleston

While I thoroughly appreciate the United States testing-machine at the Watertown Arsenal, and regard it as the most accurate testing-machine that has yet been built, I wish that I could say that it is complete in all respects. I not only fully appreciate it, but I have given up advising thesending of material to be tested anywhere else. It is five or six times more expensive to use this machine than any of the others, but the results which are obtained from it are, I think, perfectly reliable, and of such a character that the tests are all comparable with each other. It has proved, beyond a doubt, that the system of testing specimens of' diminished area, and then calculating that the metal examined will be as many times stronger as its area is greater, is an absolutely vicious one. I am quite prepared to say, that, either from their limited size or faulty construction, most of

Jan 1, 1882

By Taner Kavas

In the present study the utilization of coal ashes that appear at the end of firing process of brick production in cement pastes was examined. Ashes with three different particle sizes of 75 µm, 106 µm and 150 µm were used to replace ordinary Portland cement (PC) as 5 % and 15 % by weight. Seven samples were prepared and physical, mechanical, chemical and microstructural analyses were carried out. The compressive and bending strength values of samples were determined at the ages of 2, 7 and 28 days. It was found that cementitious pastes with finer particle sizes possessed the highest compressive and bending strength values at all curing ages. Both values after 2 and 7 days cure increased with an increase in ash content, no matter what the particle sizes of ashes were. However, strength decreased after 28 days cure as a result of ash addition of 15 %, although it was still above that of the PC.

Jan 1, 2006

W. E. RUDER, Schenectady, N. Y. (written discussion?).-To many members of the Institute, papers like this one by Prof. Jeffries, and that on "Reversal of Inheritance" by Prof. Howe, may seem highly academic. Aside from their direct application to all heat-treating processes, to my mind, the establishment of a physical fact and the correlation of facts into a definite law are in themselves ample justification for immense effort. A law, once established, cannot be ignored by those who carry the work along to practical ends. In studying both papers, it seems to me that each author is more concerned with defending a theory than with explaining the individual results as published by various investigators. Take, for example, my sample of pressed electrolytic iron, frequently referred to by both. Prof. Howe, defending inheritance, says that the grains on the second (1300° C.) heating inherited their size from the mother austenite. Prof. Jeffries, defending reversed inheritance, elabor-.

Jan 4, 1918

By Eldridge B. J

During recent years, Central Queensland has experienced a boom in its coal mining industry. This has involved many companies in projects requiring large capital expenditure. As with most projects of this size, many operating problems are now being experienced which were unforseen at the feasibility stage. One of these problems is the failure of pit slopes and spoil piles at some of the strip mining operations. There have been serious stability problems associated with Utah Development Company's strip mining operations in Central Queensland, in particular the Goonyella Mine. A field investigation programme was under- taken to determine the cause of highwall and spoilpile slope failures. Spoilpile failures were found to result from weakness near the spoil/floor contact zone. Highwall failures were found to result from a combination of unfavourable bedding plane dips and weakness, and the presence of joints in weak o~erburdep; Satisfactory solutions fa the staiity, problems are difficult to formulate, and-field stability experimentation is still at an early Stage.

Jan 1, 1974

By F. N. Kissell, C. D. Litton

This study ranks the factors impacting survival during a coal mine fire. It has already been established that reducing time delays is the most important factor in saving lives. Consequently, every event during afire is measured in terms of its duration, and the effectiveness of any action taken to improve survival is measured in terms of the time it saves. By ranking actions according to time saved, these authors found that a combination of actions was most effective. This combination was: •installing lifelines, •moderately decreasing air leakage and •decreasing the fire growth rate. Changing ventilation leakage alone was much less effective, as was altering the CO (carbon monoxide), sensor alarm threshold. These results confirm an earlier fault-tree study on escape from mine fires. The fault-tree study had shown that, with the exception of delays, single-factor changes have minimal impact. Significant reductions in fire fatalities only take place with multiple factor changes.

Jan 1, 1994

By Thomas Elliott

It is now clearly evident that 1963 is witnessing a record year for prospecting and exploration in British Columbia and Yukon Territory, as substantiated by the following facts: ? About 60 large mining companies and many smaller ones are active in the search for new ore deposits. ? More than 500 prospectors and exploration geologists have been in the field this season. ? It is estimated that $10 million has been spent this year on the search for new ore deposits. ? Claim staking in B. C. to July 31, totalling 14,250, is up 2000 over 1962. ? Helicopter companies report a record total of 25 aircraft chartered to mining groups, with additional numbers used in oil-gas exploration. ? Leading assayers state that business with the industry is double that of the previous year. ? Diamond drillers report an increase of approximately 25% in the amount of contracts now on hand. The question is often asked, "Why is mining so active in Canada's Pacific Northwest?"

Jan 12, 1963

By John B. Gustavson, Thornton L. Neathery

A geochemical survey was conducted in the gold district in Alabama. Eight old mines were found to be sufficiently large in tenor and tonnage to be economical today. Four of these appeared to be amenable to exploration for new blind deposits. A gaseous aspiration AA method was used on soil samples. The results indicate that arsenic, antimony, and zinc may be good pathfinders for lode gold and residual placers in the saprolite. Antimony and zinc display a high correlation coefficient at gold-bearing locations in contrast to non-mineralized areas. The low cost of this method could make it a tool for selecting detailed targets to be drilled and trenched in the saprolite. Outcrop sampling was found to be inefficient due to paucity of outcrops and lack of correlation between the trace elements and gold in the rock samples, due to extensive weathering. Schistosity changes and silicification, on the other hand, have been found to be helpful in exploration around granite plutons.

Jan 1, 1977

By Paul F. Richardson

Liquids containing suspended solids are encountered in most mineral processing applications. Solids levels cover a very wide range, from ppm levels in cooling water systems to slurries containing greater than 70% solids. When the aqueous phase is recycled or further processed, a solid/liquid separation process is used. Chemical additives used to carry out this process are called coagulants and flocculants. In other cases, one seeks to control or modify the properties of the suspension. Dispersants are chemicals used to aid in suspending solids in a liquid as well as to control the properties of the resulting suspension. Dispersants find a range of uses in mining and mineral processing such as scale control, filter aids, flotation aids, and slurry viscosity modification. Materials used as dispersants include inorganic salts, alkalies, organic surfactants, and polyelectrolytes. This paper discusses the use of dispersants in mineral processing, with an emphasis on control of slurry viscosity. The mechanism of dispersion and factors that affect the choice of dispersant will be discussed.

Jan 1, 1986

By H. M. Faust

THERE are a number of different types of power plants. Some use coal to generate steam, others use oil or gas either in the form of steam or internal combustion equipment, while still others avail themselves of water power as a source of energy. A general comparison of the relative power production with different sources of energy in the United States, for several different years is set up in Table 1. This table shows that coal was used to generate 85.6 per cent of the total heat power requirements of 1909, and only 59.2 per cent of the 1930 requirements. The increasing proportion of modern heat energy generated by the use of fuel other than coal is apparent. If coal is to maintain its importance as a source of heat energy, the necessity for its improved perform-ance, in which preparation plays an -important part, cannot be stressed too strongly.

Jan 1, 1933

To assist coal mine operators and regulatory agencies in selecting the most appropriate method to treat coal mine drainage utilizing expert system computer technology. The software package is called the Coal Mine Drainage Treatment PRO. Approach Experts in the field of coal mine drainage treatment were interviewed to determine their methods of assessing mine drainage treatment problems and their rationale for selecting a treatment protocol. These diagnostic, selection, and design criteria were codified in an interactive set of computer programs. Expert systems permit the user to input specific site data and receive treatment advice customized to the user's site and treatment objectives. How It Works The Coal Mine Drainage Treatment PRO package developed by the U.S. Bureau of Mines (USBM) consists of four programs or modules: (1) a control module, (2) a mine drainage treatment tutorial module, (3) a treatment advice module, and (4) a reference module (figure 1). A context-sensitive HELP Facility is also provided.

Jan 1, 1996