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By Claudia Gasparrini

"The ore microscope and electron microprobe, two common instruments for academic research, have not been used to full advantage in the Canadian mining industry, perhaps because they are not readily available to most mining companies.The present paper gives a description of the two instruments and of the manner in which, when used together, they contribute to the identification and description of mineralogical and metallurgical samples, and reviews the applications, to . date, in the mineral industry.The metallurgical applications can assist in determining the best separation technique for a particular metal or other economically important element, can provide explanations for poor recovery and/or liberation, can be used to determine theoptimum concentrate grade and can indicate environmental problems that may arise from the extraction process.In certain cases, the use of the two instruments may assist in the evaluation of new mineral deposits and in the determination of the origin of mineralization.IntroductionThe ore microscope and electron microprobe, two widely used instruments in universities and other research institutions, have not been exploited to their full potential by the Canadian mining industry.High-magnification, high-resolution ore microscopes, owned by most Canadian universities and government mining branches, are not widely used by mining organizations. The situation is very much the same with the microprobe. The geology departments of several major Canadian universities have easy access to this instrument. Fifteen of them, to the author's knowledge, own one and a few have already acquired or are planning on acquiring a second and later model. The mining branches of the Canadian Government have similar easy access to microprobes, as at least four of these instruments are available to them in Ottawa alone. The mining companies, on the other hand, except for the few larger ones which have their own research laboratories, have not been able to take advantage of electron microprobes in the past.This failure to exploit good ore microscopes and electron microprobes has been mainly due to a lack of expertise in the use of the two instruments for the study of metallurgical problems related to ore mineralogy. Government institutions providing research and test work to the industry are few in number, and are not always equipped with these instruments or are not geologically-oriented. Information provided on a consulting basis by universities and by government mining branches is normally limited, and frequently is not oriented to the needs of the mining company."

Jan 1, 1980

The Bureau of Mines studied blast-produced ground vibration from surface mining to assess its damage and annoyance potential, and to determine safe levels and appropriate measurement techniques. Direct measurements were made of ground-vibration-produced structure responses and damage in 76 homes for 219 production blasts. These results were combined with damage data from nine other blasting studies, including the three analyzed previously for Bureau of Mines Bulletin 656. Save levels of ground vibration from blasting range from 0.5 to 2.0 in/sec peak particle velocity for residential-type structures. The damage threshold values are functions of the frequencies of the vibration transmitted into the residences and the types of construction. Particularly serious are the low-frequency vibrations that exist in soft foundation materials and/or result from long blast-to-residence distances. These vibrations produce not only structure resonances (4 to 12 Hz for whole structures and 10 to 25 Hz for mid walls) but also excessive levels of displacement and strain. Threshold damage was defined as the occurrence of cosmetic damage; that is, the most superficial interior cracking of the type that develops in all homes independent of blasting. Homes with plastered interior walls are more susceptible to blast-produced cracking then modern gypsum wallboard; the latter are adequately protected by a minimum particle velocity of approximately 0.75 in/ sec for frequencies below 40 Hz. Structure response amplification factors were measured; typical values were 1.5 for structures as a whole (racking) and 4 for midwalls, at their respective resonance frequencies. For blast vibrations above 40 Hz, all amplification factors for frame residential structures were less than unity. The human response and annoyance problem from ground vibration is aggravated by wall rattling, secondary noises, and the presence of airblast. Approximately 5 to 10 pct of the neighbors will judge peak particle velocity levels of 0.5 to 0.75 in/sec as "less than acceptable" (i.e., unacceptable) based on direct reactions to the vibration. Even lower levels cause psychological response problems, and thus social, economic, and public relations factors become critical for continued blasting.

Jan 1, 1980

By Randhir S. Sehgal

After some decades of lying low and being treated as a second rate fuel, coal is back in the news. Production is rising. Predictions are for an ever expanding use, and they differ only in their rates of increase. Even the FBI is involved in trying to stop fraudulent sales of non-existent coal lands and leases to the innocent. In short, we have a nearly chaotic boom on our hands. Obviously our energy production base is in the process of undergoing a major shift, and the process will present many problems. However, there is little doubt that the industry has the basic strength and organization to be able to deal with the new issues that will arise as a result of these shifts in production and use of coal. After all, it does produce nearly 800 M tpy now, and coal is the single biggest fuel for generation of electricity. This role of coal is illustrated in the table below, which shows the coal equivalent quantities of various fuels used in the production of electricity.

Jan 1, 1980

By Milford L. Skow

This report summarizes the principal activities and results of 15 years of research by the Bureau of Mines, U.S. Department of the Interior, on methane control in coal mines. This research has investigated fundamental factors regarding the occurrence and movement of methane in coal beds, removal of methane prior to mining, and control of methane during mining. The report includes a bibliography listing the more than 150 publications resulting from the Bureau's methane control program as well as numerous other references, a section on methane recovery and use, a look at the upcoming Bureau of Mines research program, and a brief review of methane drainage practices in other coal-producing countries.

Jan 1, 1980

By S. D. Maksimovic

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by the Bureau of Mines. This report describes three gob degasification studies conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole. The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore-hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By David R. Alison

This study was conducted using field interview methods to determine the data and information requirements of the underground coal mining industry for improving mine ground control procedures in existing and future mines. The establishment of a central geologic and engineering information resource center with computer searchable abstract files that can locate and supply descriptive and case-study literature addressing specific mining problems is recommended. Research done under Bureau of Mines Contract J0395010, includes a Bibliography of Underground Coal Mine Ground Control Literature.

Jan 1, 1980

By E. H. Izen

A thermal imaging borehole probe was designed and fabricated for the purpose of obtaining thermal images, through smoke, of objects and people in underground mines. The effort was basically unsuccessful; electrical noise, and possibly thermal noise, interferred with the desired signals to the extent that spatial resolution in the images was unacceptable.

Jan 1, 1980

By Chin Wei Yang

Linear programming (LP) has proven to be a most effective mechanism for modeling a vast array of practical problems, while the development of LP applications in engineering have been extensive enough to show its advantages and limitations. In this paper: we focus on the properties of the widely-wed linear programming transportation (LPT) model formulated and developed by Koopmans (1) . There have been many models of this type applied especially in the field of energy economics (2-7). Since most of these applications can be linked to the seminal work of Henderson (8), we stall present our discussions based on his work.

Jan 1, 1980

By Theodore Christos

The Bureau of Mines sponsored an investigation of the thermal oxidative degradation characteristics of certain solvents and hydraulic fluids used in underground mining operations. The following halogenated solvents were studied in view of their usefulness and their flame retardant property: tetrachloroethylene, C12C = CC12; 1, 1, 2-trichloroethane, CIH2CCHC12: and trichloroethylene, C12C = CHC1. The hydraulic fluids studied were representative of five groups approved by the Mine Safety and Health Administration for underground operation, namely: glycol-water solutions, mineral oil-water emulsions, synthetics other than phosphate esters, synthetic phosphate esters, and mixtures of phosphate esters with mineral oils and other ingredients. It was observed that the partially halogenated solvents present a greater potential toxic hazard than the fully halogenated materials, due not only to the easy production of hydrogen chloride but also to their ease of oxidation leading to the formation of phosgene and carbon monoxide. The pure phosphate esters exhibited the best thermal oxidative stability of the five groups of hydraulic fluids tested. A fluid containing phosphate esters mixed with mineral oils and other unidentified ingredients appeared to be the most hazardous On the basis that it produced very toxic acrolein and phosphine.

Jan 1, 1980

The object of this program was to extend the capabilities of visual paging systems both in size and function. The system developed uses the mine pager phone line for communication, monitoring, and remote control. A central station, using a minicomputer, transmits signals by phase inversion modulation of a 16,384 Hz carrier to as many as 999 remote units. The remote unit addressed returns An echo to indicate that it is functioning and, in the case of monitor units, to convey the monitor data. Magnetically latched display dis[c]s, which can be seen from both sides when posted, are used for visual paging. Lists of the addresses of posted pages, unanswered pages, and non-echoing units are prepared by the central station computer. The system was designed to be intrinsically safe and should operate for three months on a 12-volt lantern battery.

Jan 1, 1980

By W. N. Marchant

[The citrate process for flue gas desulfurization (FGD) is a product of continuing research by the U.S. Bureau of Mines to meet the goal of minimizing the objectionable effects of minerals industry operations upon the environment. The reduction of SO2, in solution by H2S to produce elemental sulfur by the citrate process is extremely complex and results in solutions that contain at least nine different sulfur species. Process solution analysis is essential to a clear understanding of process chemistry and its safe, efficient operation. The various, chemical species, the approximate ranges of their concentrations in citrate process solutions, and the analytical methods evolved to determine them are hydrogen sulfide (~0M to 0.06M) by specific ion electrode, polysulfides (unknown) by ultraviolet (UV) spectrophotometry, elemental sulfur (~0M to -0.001M dissolved, ~0M to ~0.1M suspended) by W spectrophotometry, thiosulfatc (~0M to ~0.25M) by iodometry or high performance liquid chromatography (HPLC), polythionates (~0M to ~0.01M) by thin layer chrornatogrphy (TLC), dithionite (searched for but~ not detected in process solutions) by polarography or TLC, bisulfite (~0M to 0.2M) by iodometry, sulfate (~0M to 1M) by a Bureau-developed gravimetric procedure, citric acid (-GM to 0.5M) by titration or visible colorimetry, glycolic acid (~0M to 1N) by HPLC, sodium (~1.5M) by flame photo¬metry, and chloride by argentometric titration.]

Jan 1, 1980

By James O. Glanville

Ice frozen from a dilute chemical solution is mechanically weaker than ice frozen from pure water. This phenomenon is the basis of a practical method for reducing the strength of a mass of frozen coal. If a chemical additive is applied to moist coal, prior to its shipment during freezing weather, the resulting frozen coal can be more easily broken than in the absence of the chemical additive. This greatly expedites the unloading and handling of coal during winter. There has been considerable research into the nature and mechanical strength of ice frozen from various solutions. The literature relating to this process has been reviewed as has the literature relating to the chemical treatment of coal and mineral particulates. Some important articles are discussed and speculations are made about the nature of the ice-weakening process. A laboratory evaluation of the effects of chemical additives on the mechanical strength of ice and frozen coal has been made. An apparatus designed for this purpose is described, and some results obtained with it are discussed.

Jan 1, 1980

By R. L. Loofbourow

Most wet mines face unquantified water costs as well as the obvious wing costs. Both kinds of cost are multiplied by work at greater depth and by higher unit prices. This intensified challenge merits renewed or perhaps altogether new response. Any practicable way to reduce inflow tackles both obvious and unquantified costs. Ten groups of possible ways to do it are cited. Most have been demonstrated. Two are known from work other than mining. Surely new means can be found. Here are opportunities for operators of wet mines!

Jan 1, 1980

By William H. Holley

Thirteen additional preservative/fire retardant systems were applied to Ponderosa pine and evaluated for flammability both before and after water leaching. The more promising four systems were given a thorough evaluation for flame spread, toxic gas and smoke density levels, resistance to decay, and compressive strength. The most promising system on the basis of history of usage in the mine, ease of application and low cost as well as overall performance is the Fyreprufe/ACC Albi 107A/ 144 combination. A survey of inspection tools and instruments, identified equipment which could be assembled into an inspection kit for use in determining the extent of decay and/ or impregnant retention levels in mine timber. A literature search identified those high fire hazard areas found in a typical mine. Timber and other wooden structures used in such areas should be treated with an acceptable fire retardant system. A survey of insurance companies revealed that the use of such treated timber in the mines would probably have little or no impact on the rate structure.

Jan 1, 1980

By R Hoskings

Conceptual studies of the run of mine stockpiling and reclaiming requirements commenced in 1975. Final selection of equipment was made in 1978 and the equipment was commissioned in June, 1979. Equipment selection was made after extensive investigation and visits to existing facilities throughout the world. The equipment selected is described and compared with the alternatives. Foundations were designed to minimise cleanup effort and to ensure stability of equipment under design wind loading without storm bays. Programmable logic control enables the stacking and reclaiming facility to provide a blended feed to the coal preparation plant.

Jan 1, 1980

By D. W. Dareing

Multiple branch wellbores and horizontal holes, when applied to deep lying ore bodies, have the potential of significantly reducing well costs by reducing total footage drilled per acre of well pattern. In addition, horizontal holes may increase sweep efficiency. Well completion is a major problem. They must be cased to contain leaching solutions within the underground portion of the production loop. Several drilling and completion concepts are given and evaluated in the report. Our evaluation shows that there is economic incentive to further develop these concepts for field application to ore bodies 1,500 feet. Multiple branch concepts are the most attractive. They can reduce well costs by as much as 30° when applied to 2,000 feet ore body depths (44%, at 5,000 feet) and can accommodate a lamer pump than conventional vertical wells. We recommend this concept be developed further to accommodate either dual or triple branches.

Jan 1, 1980

This publication summarizes the in-house and contract research and development projects programed for fiscal pear 1980 by the Bureau of Mines under its Minerals Environmental Research activity. The document provides a mechanism for interested parties, including potential contractors, to gain insight into ongoing and projected work of the Bureau's environmental research efforts. Research to identify and correct environmental problems associated with mining and metallurgical operations has long been an integral part of the Bureau's mission. Through the years, efforts of various Bureau programs have yielded valuable information on the origin and control of many of these problems. With the reorganization of the Bureau of Mines in 1979, the Minerals Environmental Technology program was structured to consolidate these efforts into a single program that will systematically investigate al aspects of mining- and processing-related environmental pollution and damage-from initial discovery of the mineral resource to ultimate return of the land to productive use. In fiscal year 1980, the Bureau received an appropriation of about $21 million to conduct research and development work on these problems.

Jan 1, 1980

By Peter P. Kopas

Study, analysis, fabrication and testing for canopies on Roof Bolters and Shuttle Cars in coal seams under 48?.

Jan 1, 1980

By David D. Rabb

A report on location, sampling, assays, mineral examination, amenability leach tests, and evaluation of certain mine dumps in Mohave County, Arizona. Extractions of greater than 30 percent of the gold and silver were achieved during simulated heap leaching of selected mine dump material. Consumption of reagents was relatively low and results suggest leaching of prepared heaps is technically viable and could be economically attractive.

Jan 1, 1980

By D. Pearson

About 15,000 tonnes of zinc per year is present in the dusts and fumes produced in electric arc and BOS steelmaking, secondary copper refining and brass ingot making. Apart from the use of some copper-smelter fumes for zinc chemicals manufacture, zinc is not recovered and their disposal by landfill entails some risk of pollution by leach-out. The paper describes processes for recovering the zinc based on leaching and electrowinning. It was shown that the procedures normally employed for purifying zinc-electrolytes derived from primary sources are sometimes ineffective for secondary materials. Alternative process routes are proposed. Source materials were leached with acidic or alkaline reagents and solvent extraction was employed for electrolyte purification in addition to the usual techniques involving precipitation. Examples of integrated flow sheets for specific source materials are presented.

Jan 1, 1980