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By A. H. Srnallbone

Over the past few years the rising production costs, shortage of skilled labor, and increased use of lower grade ore bodies have all added justification for the use of on-stream analysis. A rise in the number of on-stream units indicates that this type of assay is now being accepted as a necessity. On-stream analysis is a much more rapid means of obtaining true assays of a flowing product when compared to wet chemistry or "grab" samples dried, briquetted and assayed by x-ray. In contrast, on-stream analysis uses real time samples assayed every 30 seconds while each stream is assayed every 5 to 15 minutes. It is very important not only to know that a change has occurred in the process, but to know what caused the change and how to correct for the change. For example, in a tailing sample the elements of interest comprise between 1% and 10% of the sample. The remainder is water and gangue. Previously the gangue was not assayed nor were the low atomic number elements used for corrections. In addition to the demand for higher accuracies some concentrators were being penalized for excessive Ca or in some cases 5i in their concentrates. This penalty was being imposed by the smelter in order that they could better cope with pollution problems and prolong the life of their furnaces. But until Ca, 5i, and S are measured on-line, nothing can be done about their control. By accurately measuring these light elements on-line, a complete assay is obtained of the total sample providing improved accuracy for the important products. The justification for complete accuracy assays is now even more obvious because they are possible at very 1ittle increased cost and at no increase in analytical time.

Jan 1, 1977

By F. Ikumapayi

In order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the influence of major species, calcium and sulfate in process water on sphalerite flotation was investigated through Hallimond tube flotation, zeta potential, diffuse reflectance Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements using sphalerite mineral sample. Assessment of process water species in flotation was done using deionized water, process water and simulated water containing calcium and sulfate ions in experiments. Hallimond flotation shows increased sphalerite float-ability in process water compared to deionized water, but no significant effect on the presence of calcium and sulfate ions in deionized water using isobutyl xanthate as a collector. The presence of calcium ions reduced the sphalerite?s negative zeta potential, while at higher concentrations, a charge reversal occurred, at about pH 11. FTIR and XPS studies revealed the presence of surface-oxidized sulfoxy and carbonate species on sphalerite at pH 11.5 in deionized water, process water and water containing calcium and sulfate ions. These surface species do not influence xanthate adsorption.

By J. E. Sepulveda

Tar sand deposits in the. Stare of Utah contain more than 25 billion barrels of in-place bitumen, Although thirty times smaller than the well-known Athabasca tar sands, Utah tar sands do represent a significant domestic energy resource comparable to the national crude oil reserves (31.3 billion barrels), The term "tar sand" refers to a consolidated mixture of bitumen and sand, Based upon a detailed analysis of the physical and chemical properties of both the bitumen and the sand, a hot-water extraction process for Utah tar sands is currently being developed in our laboratories at the University of Utah. This process involves intense agitation of the tar sand in a hot caustic solution and subsequent separation of the bitumen by a modified froth flotation technique., Experimental results indicated that, for a given tar sand sample, percent solids and caustic concentration were the two most important variables controlling the performance of the digestion stage, These variables were identified by means of an experimental, factorial design, in which coefficients of separation greater than 0.90 were realized. Although preliminary in nature, the experimental evidence gathered in this investigation seems to indicate that a hot-water extraction process for Utah tar sands would allow for the efficient utilization of this important energy resource.

Jan 1, 1978

By K. Yatsunami

NKK has developed a new cold bonded pellet process. The features of this process are; 1) it is a continuous process with 10 hours curing. 2) Products can be used as materials for various metallurgical furnaces. 3) Various kinds of slag are used as binders if necessary. 4) The quality of products is excellent. The pilot plant completed in 1981 is now being successfully operated. We are also constructing a commercial plant at our Niigata works. We produced cold pellets containing carbon as material for ferroalloys (Si-Mn), by pilot plant and used them in furnaces. Consequently, considerable economic advantages were obtained.

Jan 1, 1984

By Y. J. Wang

In the mathematical analysis of electrical networks, the electrical devices are often modeled using idealized network elements such as current sources, voltage sources, and resistors. An analogous approach is outlined here for the modeling of mine ventilation networks, which can be considered nonlinear resistive networks. The modeling technique proposed uses five basic (non-reducible) elements: the H element, the Q element, the D element, the R element, and the N element. These elements are characterized by their (a) pressure gain or loss, (b) air quantity, and (c) pressure-versus-quantity relationship, each of which may be known or unknown. In addition to the definition of the basic elements, the necessary conditions for which there exists a unique solution are discussed. This is performed using theoretical developments derived from electrical circuit theory and illustrated in example networks. The proposed procedures are useful in the solution and characterization of mine ventilation networks.

Jan 1, 1996

By CASSANDRA L. HOEBBEL, Emily J. Haas, MARGARET E. RYAN

In recent years, there has been increasing interest in the role that individual factors play in health and safety (H&S) outcomes in the mining industry. Two surveys, one measuring self-reported routine safety performance and one measuring individual perceived competence in the non-routine knowledge, skills, and abilities (KSAs) critical to emergency response, were administered to two samples of mineworkers in separate research studies over a 2-year period (N=2,020 and 696, respectively). Eight demographic items were common to both surveys and their associations with each performance outcome were tested in response to a series of exploratory research questions.

Jan 9, 2022

By James E. Lawver

The agriculture industry has made great strides during the past decade to increase agriculture yields through increased use of fertilizers. Increased use of fertilizers may prevent or at least delay mass starvation due to the alarming increase in world population. Phosphate was added to soil as a plant nutrient in the forms of calcined bones at least 2 000 years ago, (1) and man has used phosphate minerals as a source of fertilizers in one form or another for at least 100 years. During 1977 the world produced about 116 million metric tons of phosphate rock, with about 86% used for fertilizers and another 4% for animal feed supplements. More than three-fourths of the total production comes from the United States, Morocco, and the Soviet Union. From a mineral beneficiation point of view, the major sources of phosphate rock and the methods of beneficiation can be classified as follows. Marine deposits not containing appreciable carbonate minerals, marine deposits requiring a francolite carbonate mineral separation, igneous deposits not containing appreciable carbonate minerals, and igneous deposits, requiring an apatite carbonate mineral separation.

Jan 1, 1978

By Iwasaki I.

This article discusses the effect of physical and chemical modifications of starches on the anionic and cationic flotation of silica from oxidized iron ores and magnetite-taconite concentrates, and the results of the interaction of starch, pH, and calcium ions on the flocculation, clarification, and filtration of iron ore slimes and magnetite-taconite tailings. Starches, particularly when anionically modified, were found to be effective depressants in anionic silica flotation. British gums and dextrins were beneficial for oxidized iron ores, but none of the starches or starch derivatives appeared to have any effect on magnetite-taconite concentrates. The flocculation and filtration of iron ore slimes were most strongly affected by the level of starch, to a lesser degree by the pH, and were virtually independent of the level of calcium chloride. The clarification of iron ore slimes was complexly dependent on these three factors. The flocculation of magnetite-taconite tailings depended mainly on the level of starch, whereas their clarification depended on the level of lime. As previously reported in the literature, selective flocculation and partial upgrading of a semi-taconite could be readily attained with starch and calcium chloride.

Jan 1, 1968

By Linda J. Dahl

The U.S. Department of the Interior, Bureau of Mines is developing a process to selectively extract manganese from oxide ores as part of its in situ leach mining research program. The Bureau is conducting site characterization studies of two manganiferous iron-formation deposits which include: drill core, regional stratigraphic relationships from the existing geologic database, ore body geometry, geologic structure, hydrologic conditions, proximity of ore minerals to the leach fluid paths, surface subsidence potential, and data collected from laboratory leaching experiments. This information is being used to evaluate the technical, environmental, and economic feasibility of in situ leach mining of manganese for these two deposits. This paper will focus on the stratigraphy, mineralogy, ore textures, fractures, permeability, and porosity as they relate to in situ leach mining.

Jan 1, 1992

By M. K. Mohanty

Due to inefficiencies of the flotation process, significant effort has been recently provided to develop gravity separators for treating ultrafine particles. As a result, several enhanced gravity concentrators have been developed and commercialized. The Altair Centrifugal Jig is an enhanced gravity separator that provides relatively efficient separations on +25 µm size fractions. An experimental program conducted on -600 µm coal found that the Altair Jig reduced the ash content of the 600 x 44 µm from about 30% to 10% with an 86% combustible recovery value. The pulse water pressure, feed volumetric rate and ragging volume were found to be the key operating parameters affecting the separation performances obtained from the process. An extremely low density cut point of 1.54 and an Ep value of 0.08 were indicative of the high process efficiency values achievable by the Altair jig.

Jan 1, 1998

By James R. Strong

Before getting into the subject of packaging and materials management, please permit me to introduce you to MICRO SWITCH. MICRO SWITCH, A Division of Honeywell Inc. is located in Freeport, Illinois. We manufacture and market thousands of types of precision snap-action electrical switches. Most of them are used as components by other manufacturers in industrial and commercial products. MICRO SWITCH also offers a broad line of industrial control devices including heavy- duty limit switches, relays, manual controls and proximity switches. Other product lines are solid state keyboards for the computer industry and high-performance d.c. motors used in computer related equipment. So you can see that we are a component manufacturer. With the exception of the keyboards, every one of our products would "fit comfortably into a breadbox." Some are so tiny that one could easily fit several thousand into a man's hat. In my position as supervisor-packaging. package design, and materials handling engineering, I am actively involved in package design projects, parts handling design projects, and numerous activities involving departmental layouts, storage facilities, and material handling equipment. Two package design technicians, a materials handling engineer, and a materials handling technician make up the technical staff.

Jan 1, 1973

By Davar Abi-Zadeh, Cillian Brown, Deepak Kandra

"Grout backfill strategy for a particular subsurface concrete tunnel (~4.9km long, 3.5m in diameter, carrying 20” gas pipeline) was based on achieving 1:100 slope of the fill in order to progressively fill the tunnel, in a series of 350m section. Grout rheology, particularly its non-Newtonian and thixotropic behavior, determines the final fill slope for given backfill strategy. The objective of this study was to simulate the two-phase grout mix backfill process using Computational Fluid Dynamics (CFD) and determine the slope of the fill to validate and optimize the backfill strategy. Three dimensional CFD study showed that for a 500m long tunnel section with a single injection point of grout, given its rheology, it will likely keep flowing without filling the 500m section height wise. Design optimization for filling was carried out using two dimensional studies to make the backfill process “slope independent” by incorporating a 2.5m high bulkhead at ~1,000m. INTRODUCTION As part of a gas field development a 20” onshore gas pipeline is required from the landfall site to the processing terminal some 8km inland. At the landfall site the gas pipeline is routed in a ~5km underground tunnel underneath a bay. For operational reasons and planning consents as well as to mitigate environmental impact based on an environmental impact study, once the gas pipeline and the associated services and spares have been installed, the subsurface gas tunnel will be fully grouted. There will be no permanent access to the tunnel after construction is completed and the site compounds have been reinstated once works are complete. One of the key requirements is that “full grouting of the tunnel” is desired. The grouting material used is a non-Newtonian and thixotropic fluid mixture of bentonite, cement, plasticizer, retarder/stabilizer and water. The tunnel is filled progressively in 350m sections using a combination of existing and new pipework assuming the grout rheology will yield a fill slope of 1:100 in a 350m section. The proposed grouting system used one pump at the grouting compound to pump the grout into the tunnel using the existing tunneling pipework. For the longer runs a second booster pump was used in series to pump the grout to its final discharge location. The filling process is controlled via a system of flow meters, pressure transmitters and a tunnel CCTV system."

Jan 1, 2016

By J. B. Offei, K. Awuah-Offei

Mining companies registered with the SEC were required to comply with Regulation S-K 1300 for their annual report covering the first fiscal year ending on or after January 1, 2021. Consequently, most mining registrants filed their first S-K 1300 compliant disclosures in 2022. The US Securities & Exchange Commission (SEC), as part of its disclosure review program, has been issuing comment letters in response to these filings. This paper presents an overview of the trends in these comment letters. The authors reviewed comment letters retrieved from the SEC’s EDGAR database based on Standard Industrial Classification (SIC) Codes that cover mining, the content of the comment letter (whether it references S-K 1300 or not), the names of SEC staff listed in the comment letters, and other criteria. The analysis shows the SEC staff's reviews have been comprehensive covering the breadth of S-K 1300 and eliciting compliance with the rule. The staff through their comments are eliciting all the disclosures required by S-K 1300 and are not allowing registrants to substitute disclosures based on other standards for S-K 1300 disclosures. It is important, however, not to over generalize as the comments are based on the particular context.

Feb 1, 2023

By F. H. Buttner

Commodity currency intrigues most of us because of the problems it offers to solve for the Third and the First Worlds. What problems might be solved, if commodity currency were to be adopted in the Third World? That is really the question we are probing here right now. It would take a while to think through all their subtle consequences of this question, but, off the top, it might well have at least three important impacts. Most important of these to this audience is relief from unfair Third World competition. Second, it might well liberate Third World economies from financial indebtedness to the First World and give them freedom from the liquidity limitations. The third benefit is that it might help relieve World trade tensions. All three benefits are interrelated. We could start our speculations on the application of commodity currency from anyone of these starting points. But let us use the starting point most important to you, unfair competition to the U.S. mining industry. From there we might wind up with some thoughts on things you, yourselves, can do to improve things.

Jan 1, 1978

By Roy A. Grancher

HAPPY BIRTHDAY Not only is 1971 the Centennial Year of the AIME, but it also marks the One Hundredth Anniversary of the United States Portland Cement Industry. On September 26th in 1871 David O. Saylor of Allentown, Pennsylvania, received his patent Numbered 119,413 for the manufacture of portland cement. "Cement" had been used in the United States before that. This was, however, natural cement - a direct product of rocks as found in nature, usually burned at low temperatures in open kilns. During the early 1800s this natural cement played an important role in such projects as the building of the Erie Canal. It was only after the Civil War that small amounts of high priced portland cement was imported from Europe. The successful use of this material in construction led to Saylor's experiments and subsequent patent for the manufacture of a scientifically controlled product in this country. These one hundred years have witnessed four major "ages" of cement . . . three of them occurring in the last quarter century since World War Two. The first age was the "Age of Development", a seventy-year period which saw the growth of cement and its concrete end uses as major construction materials. Next followed a period called the "Age of Demand" when, after the war, cement became in short supply relative to large building requirements. In effect a cement shortage existed. The decade of the Sixties proved to be the "Age of Reaction", with its courses of action coming in response to the problems that arose when the industry's expansion programs provided too much capacity. Today cement, and the concrete industries, find themselves entering the "Age of Reason". Overcapacity, low price, rising costs, and poor returns are several of the reasons behind that name, As these industries face the construction challenge of the Seventies, and beyond, the application of basic management principles (otherwise known

Jan 1, 1971

By K. E. Burgher

Since World War II, the need for the use of explosives in construction, mining, and quarrying near congested urban areas has increased dramatically. Often times a coal mine, once isolated from a city, finds itself surrounded by residential and commercial structures. The United States Bureau of Mines and others have researched blast design to a point where ground vibration and airblast damage can be avoided. A problem still exists, however. It is the fact that people often react to only the loud noise associated with a blast although it may not cause damage. Most often it is the concussion of a blast, less than 20 hertz and inaudible, that produces damage. Public fear from the "startle" and "fright" of loud blast noise greater than 20 hertz leads to the complaints which are generally unfounded. See Thackray, Touchstone, and Baily (1975) for a further discussion of the startle effects of loud sudden noises. When blasts are designed in accordance with U.S.B.M. specifications, management generally has little to worry about with respect to damage claims. Complaints, however, still arise when the noise is accentuated from the blast. It is meteorological conditions which dictate how the sound levels will propagate. Some mines use small pilot test shots (generally one-two lbs) to determine when atmospheric conditions favor sound travel.

Jan 1, 1987

By Howard M. Wells

Portfolio theory and the Capital Asset Pricing Model (Modigliani and Pogue, 1974) provides an investment decision rationale which takes account of the benefits of diversification in reducing effective risk, but this theory does not consider the financial capability of the firm to survive large losses if they should occur. The LL-curve theory (Wells, 1976) takes the latter consideration into account, but it does not provide for the effects of diversification. This paper pro- poses a general theory to account for both diversification and the financial capacity of the firm to underwrite the investment risks.

Jan 1, 1983

By A. R. Laplante

A test to determine the amount of gravity recoverable gold (GRG) in an ore is described. Typical GRG results are given; an error analysis is detailed; possible uses are discussed. Of the 38 samples tested, the lowest GRG content was found to be 25% (most below 25 11m, or 600 mesh), and the highest 94% (most above 300 11m, or 50 mesh). The average GRG content was 63%, with a standard deviation of 19%. Error analysis shows the test to be reproducible within 5 to 10%, depending on the size distribution and grade of GRG, and the sample extraction protocol. When using the same primary sample, reproducibility improves, 2 to 5%, depending on the amount of gold coarser than 850 11m (20 mesh) and sample weight. The test has been applied to greenfield project and retrofit applications, to determine the suitability of gravity recovery. For existing circuits, it has been coupled with a model of gravity recovery for optimization studies.

Jan 1, 1996

By J. F. Brune

"Re-occurring face ignitions in U.S. coal mines are concerning and require a closer look at air quality monitoring systems and practices employed in these mines. The explosion disaster at the Upper Big Branch mine in West Virginia in 2010 caused 29 fatal injuries and was largely caused by inadequate water sprays and inadequate ventilation monitoring. In this comparison, the author compares ventilation system monitoring in Australian, German and U.S. underground coal mines and makes recommendations for improvements and best practices. Mines in Germany and Australia are adhering to more stringent requirements for monitoring air quality and quantity and for monitoring water spray systems on cutters to prevent frictional ignitions. Air quality should to be monitored for sufficient oxygen, toxic gases, explosibility and for fire gases indicating a potential fire. Ventilation monitors must also confirm that sufficient quantities of air are available. Fully automated, continuously recording atmospheric monitoring and alarm systems are established practices in Germany and Australia and should be mandated for U.S. mines as well, in addition to the current, regular spot inspections of the ventilation system by certified mine examiners. BACKGROUND: METHANE EXPLOSIONS, FACE IGNITIONS AND NEED FOR AIR QUALITY MONITORING Accumulations of methane in face areas of underground coal mines frequently lead to ignitions that can cause burns, traumatic injuries and, in the case of the 2010 Upper Big Branch disaster, cause major explosions with multiple fatalities. Table 1 shows the number of reported face ignitions in U.S. coal mines between 2010 and 2014, based on statistical data published by MSHA (MSHA 2010 – 2014). Although there appears to be a downward trend in such ignition incidents over time, ignitions continue to occur with some regularity; and each ignition may cause a potentially catastrophic mine explosion.Per regulation, all U.S. coal mining machinery, continuous miners and longwall equipment, is outfitted with continuously monitoring methane sensors wired to cut power to the equipment as the methane level exceeds 1%. Face ignitions keep occurring because these sensors are usually not positioned in sufficiently close proximity to the coal cutting drums or to the freshly exposed coal face where the methane is most likely released. Therefore, methane may accumulate in explosive concentrations near the coal face and the cutting drums long before the gas concentration reaches the 1% level near the monitor and creates an alarm."

Jan 1, 2016

By John E. Caffrey

Mr. William. J. Montgomery in his book "Theory and Practice on Mine Ventilation stated "Ventilation is vitally important to underground mining for three reasons: First, it sweeps all workings with a plentiful supply of air and drives to the outside the smoke, gases, and contaminated air which would be injurious to the miners; second, it dilutes and renders harmless the explosive gases emitted from the strata, thus eliminating the dangerous conditions caused by the accumulation of these gases; third, it keeps the mine air as nearly as possible of the same composition as the outside air, thus giving to the miner the healthiest possible condition in which to work...." Specific methods to achieve the above basic reasons for mine ventilation were established in the Federal Coal Mine Health and Safety Act of 1969. Sections 303(y)(1); (y)(2), and Section 317(f)(4) of the Act, which can be broadly described as entrapment features, are controversial and debatable in the minds of many mining engineers in their intent and method for affecting, 303(y)(1) in certain cases prohibits the use of belt haulage entries as an intake for face ventilation, This is to say that air traveling in a belt entry will be placed into the returns and not used for face ventilation, 303(y)(2) limits the velocity of the air on trolley haulage entries. The regulations, as published in the Federal Register, have set this limit at 250 feet per minute unless a higher velocity is approved by the District Manager.

Jan 1, 1972