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By R. L. Loofbourow

SEVERAL categories of storage are used depending on capacity. Operational storage, which is small in comparison with the market, facilitates handling surges of a few hours' or a few days' duration. Seasonal storage, usually larger, permits accumulation of product during sea- sons when demand is low, for delivery when demand is high. In producing areas, large storage may permit production at a uniform rate, without waste or distress sale. Near large markets such storage increases the efficiency of transportation, allows a more extensive or higher grade market to be served, and affords protection against interruption in delivery.

Jan 1, 1959

By C. L. Lin

A PC image-based, on-line instrument for the measurement of coarse particle size on a conveyor belt is under development. Both the hardware and software required to implement such a system are discussed, including the interface for the special image acquisition hardware. The system concept is given with examples to illustrate the step-by-step procedure for the implementation of image-processing algorithms.

Jan 1, 1992

By Earl M. Woodward

INTRODUCTION Kerckhoff-2 is a 140 MW underground hydro-electric project designed and owned by Pacific Gas and Electric Company and constructed between May, 1980 and May, 1983 by Auburn Constructors. The project is located in the western foothills of the Central Sierra Nevada Mountains, about 30 miles northeast of Fresno, California, and develops the power potential of the lower San Joaquin River and its tributaries between the existing Kerckhoff and Millerton Lakes. The Kerckhoff-2 Project consists of project roads, adits, and access tunnels, service tunnels, power tunnels, powerhouse, tailrace tunnel surge shaft, buss shaft, intake structure, discharge structure, and switchyard. In the 1920s, the Kerckhoff 1 project, consisting of a dam, reservior, tunnel, and 34 MW powerhouse, was built in the same general area as Kerckhoff-2. The tunnel was constructed by conventional methods, and was left unlined. In time, other projects were built upstream, allowing the flow of the San Joaquin River to be regulated. The Kerckhoff 2 project is designed to harness that regulated flow, providing an additional 140,000 ON of power. Kerckhoff 2 will be the primary power plant; Kerckhoff I will produce power whenever the flow rate exceeds 4,800 cubic feet. The new power tunnel is built along the east side of the San Joaquin River between Kerckhoff and Millerton Lakes, parallel to the existing tunnel but extending approximately one mile further downstream.

Jan 1, 1983

By H. Soto

As a follow-up to a laboratory study, a pilot scale column for the flotation of coarse particles was designed and then tested in two different applications. In the first test, the concentration of a coarse phosphate ore (normally beneficiated by skin flotation in spirals) was carried out in a flotation plant in Florida. In the second pilot test, the column was used as a scavenger cell in the coarse flotation section of a potash beneficiation plant in Saskatchewan, Canada. Particle size of the phosphate feed was of the order of 0.6-1.0 mm and the potash feed 1-3 mm. The column was 1 feet diameter and was fed at rates between 0.5 to 1.4 tph. The effect of operating variables such as air and water flow rates, bubble size, frother concentration, residence time, sparger, etc were evaluated. The most important factors in column performance were found to be bubble size, air flow rate and the thickness of the froth bed. Best results were obtained in the absence of a froth bed, with low air flow rates and with small bubbles. The paper presents comparative performance and discusses details of the column design. Phosphate recoveries in the column were better than 90% whereas the conventional skin flotation circuit normally yields about 60% recovery for a comparable concentrate grade. Potash recovery from the tailings of the conventional flotation circuit was as high as 42% recovery. Particle size distribution of the potash concentrate was coarse enough to meet requirements for potash fertilizer.

Jan 1, 1993

By T. Owen

Not since 1917 has a foreign company developed a standalone, grass roots gold mine in Russia. With. Russia's political changes of the late 1980s, development of mineral prospects once again beckons foreign investors. In 1990, Cyprus Amax began aggressively searching for such an opportunity. Early in 1997, production will commence at the Kubaka gold project located in the Russian Far East, near the Arctic Circle. The Kubaka project is a 1,750-tonne per day open-pit operation that will produce more than 300,000 ounces of gold per year. This paper discusses the challenges of locating such a prospect, doing business in Russia, developing supply lines, identifying work force capabilities, gaining government approvals, securing financing, arranging for gold sales and ultimately building a facility in this arctic region.

Jan 1, 1997

By M. Ziegler

The article deals with the use of a digital twin in the assessment and optimization of a conveyor system in the Chilean copper mine. This example shows that a digital twin is initially just a new (albeit powerful) tool with which the system behavior can be examined. The benefits for the customer arise through the system identification and automatic detection of critical deviations from the target state. This knowledge allows mine management to react and coordinate operational and/or maintenance counter measures to insure optimal performance of their conveyor system. The information derived from the BeltGenius digital twin also allows mine management to gain a clear perspective of the overall efficiency of their conveyors, which will be invaluable for future conveyor component selections.

Mar 2, 2022

By John O. Marsden

"This article is an attempt to capture a presentation given at the 2016 SME Mineral & Metallurgical Processing Division (MPD) Luncheon held on Feb. 24, 2016, in Phoenix, AZ. It was presented as a tongue-in-cheek, lighthearted view of several of the issues facing our industry, while identifying some of the challenges and opportunities available to new engineers entering the industry today.Disclaimer• What you are about to read includes personal preferences, biases and occasionally arbitrary opinions.• Some readers may have dissimilar opinions on the contents and/or the rank order of the lists.There are eight top ten lists offered in this article: (1) Industry realities (2) Things a metallurgical or mineral process engineering graduate should do (3) Books every metallurgist should have on their shelf (4) Things I wish I had known (5) Legends of metallurgy (posthumous, with highlights) (6) Things we’ve forgotten (7) Mineral processing innovations of the past 20 years and, finally, (8) The future? For some items, additional context or clarification is provided after the item, while for other items no further explanation is warranted and none is offered. Top 10 industry realities1. Metal price cycles.2. Bigger is better (except when it isn’t).3. Ore grades declining across the board of metals/commodities.4. Ores becoming more complex.5. Three-fold increase in capital costs between 2004 and 2015.6. Three-fold increase in operating costs between 2004 and 2015.7. Less capital availability/challenging financial markets.8. Environmental constraints increasing.9. Socio-political constraints increasing.10. The mine manager is always impossible to work with.As Table 1 shows, there was more than a three-fold increase in gold operating costs between 2004 and 2014. The increases for copper, iron ore and other commodities were similar."

Aug 1, 2016

By C. C. Muir

At the outset, I believe reference should be made to comparatively recent world developments in copper which have an important bearing upon the Canadian position. COPPER SITUATION No one can doubt the marked change for the better compared with not so long ago when less than adequate attention was paid to marketing and to uses of the metal. I need not show you graphs of world copper prices, which except for relatively brief periods and war conditions were, until about three years ago, not unlike the topography of the Canadian Rockies. There remain, of course, some non-industry factors who yearn for the old days of "roller-coaster" copper prices.

Jan 1, 1964

Smart defense: that?s what the industry needs to play for the next four years, according to panelists at the 118th Annual Meeting of the Northwest Mining Association (NWMA), which met December 2-7 in Spokane, WA. The conference was well attended, with approximately 2,200 attendees, 244 booths in the two packed exhibition halls, and a rich offering of short courses, field trips, social events and technical sessions. Speakers at the packed legislative session articulated many of the frustrations felt by members of the mining community after the U.S. elections in November, and offered words of advice. Matthew Ellsworth, the new Government Affairs hire at NWMA, stated it best: ?Elections are like Christmas: you find out who?s naughty and nice ? and it?s always going to come again.?

Jan 1, 2013

By Jürgen Kretschmann

According to the model of product life cycles, the global coal mining industry is in the stagnation phase. The coal demand of the main consumer, China, has peaked in 2013 and is slowly declining. The Norwegian sovereign wealth fund, the world’s largest, has excluded coal-related companies for ethical reasons. Important players like the UN or the EU have already begun to describe pathways towards decarbonization. Increasing competition between coal mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries like France, Spain, or Germany are only forerunners of this development—their centuries of coal production have been finished. The concept of sustainable development (SD) is fundamentally based on a model of progress where ecological, economic, and social dimensions should be developed equally and positively. But without the idea of competition, the concept of SD is incomplete. Questions arise, such as how can SD be realized on stagnating or declining markets without guarantees for companies “to live forever”? How can SD be a corporate goal in a phase of decline? How can declining mining regions sustainably progress into a better future? The German hard coal mining industry’s lifecycle has ended in 2018 after 60 years of stagnation and decline. As of 2019, all hard coal consumed in Germany will be imported, especially from Colombia, Russia, and South Africa. What has been done in Germany to handle the coal decline in a sustainable way and the lessons learned from this process is described in this paper. It may be useful for mining regions who will face a similar future sooner or later.

The past decade has seen remarkable progress by the railroads both in equipment and concepts in the handling of dry bulk. materials. While such shipments have always been an important part of the traffic handled by the railroads I little was done to improve the efficiency of handling or toward attempted optimization of equipment design before 1960. Several developments at about that time turned attention to this important segment of railroad traffic. One was the construction of a successful coal slurry pipe-line. Another was the promise of substantial economy in electric power transmission by ultrahigh voltage systems and finally, came the growing technological and economic feasibility of nuclear fuel electric generating plants. Each of these developments was a threat to the coal traffic of the railroads --the most important single commodity they handled in terms of revenue and tonnage. By the mid-1950's I Southern Railway management had become most concerned with its growing investment in freight car equipment and the declining revenue productivity of the capital employed. Additionally I there was substantial concern with the loss of business and potential losses in the area of the railroad's greatest economic advantage --bulk commodity movements. In 1958 a small team was established to study this problem. They arrived at two conclusions. The first conclusion was that within limits of maximum gross allowable weight on rail the lowest unit net capacity cost of investment came at maximum allowable gross weight per car unit. The second conclusion was that with a high degree of utilization costs per weight unit transported could be reduced to the pOint where

Jan 1, 1971

By Jürgen Kretschmann

According to the model of product life cycles, the global coal mining industry is in the stagnation phase. The coal demand of the main consumer, China, has peaked in 2013 and is slowly declining. The Norwegian sovereign wealth fund, the world’s largest, has excluded coal-related companies for ethical reasons. Important players like the UN or the EU have already begun to describe pathways towards decarbonization. Increasing competition between coal mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries like France, Spain, or Germany are only forerunners of this development—their centuries of coal production have been finished. The concept of sustainable development (SD) is fundamentally based on a model of progress where ecological, economic, and social dimensions should be developed equally and positively. But without the idea of competition, the concept of SD is incomplete. Questions arise, such as how can SD be realized on stagnating or declining markets without guarantees for companies “to live forever”? How can SD be a corporate goal in a phase of decline? How can declining mining regions sustainably progress into a better future? The German hard coal mining industry’s lifecycle has ended in 2018 after 60 years of stagnation and decline. As of 2019, all hard coal consumed in Germany will be imported, especially from Colombia, Russia, and South Africa. What has been done in Germany to handle the coal decline in a sustainable way and the lessons learned from this process is described in this paper. It may be useful for mining regions who will face a similar future sooner or later.

By David Morrison

"The history of the mining industry is littered with in-pit crushing and conveying (IPCC), which should not be confused with the International Protocol for Carbon Capture, projects that failed. The failure is not the technical one of “did it achieve the desired tonnage rate for a longish test period” but, rather, the far more important one of “did it provide return on the investment in the manner that was promised?” While quite a few can claim the former, very few system installations can claim the latter.The reasons for the many failures are numerous, but they are all characterized by a combination of an element of engineering optimism in any, or all of the production rates, the productivity, or the operating and maintenance costs and in predicting the continuity of operating conditions. In these days of big data, propagating such a situation is rapidly becoming unforgivable.In this article, the three most common scenarios put to the corporate board for approval, and the logic as to why they were selected, are examined (with the irony included intentionally).• Fully mobile crusher, fed by a shovel and conveyed out of the pit to a waste dump / process plant.• Semimobile crusher (much more expensive than a fixed crushing station but which apparently allows trucks to short haul inside the pit and improve productivity), which moves when the face moves.• Relocatable crusher (more expensive than a fixed crushing station but which gets relocated at great expense after all the fixed infrastructure impeding relocation is demolished) fed by trucks that don’t leave the pit mostly.This paper will also consider the truth about their operational performance and associate costs."

Dec 1, 2016

By Mark J. Zdunczyk

"Frac sand is industrial silica sand much like glass, foundry, filtration and blast sand. The sand must meet certain specifications set forth by the industry that consumes the product. The production and consumption of frac sand has experienced record growth in the last 10 years because of new oil and gas drilling, new horizontal well drilling, multi-stage fracturing and the stimulation of older wells that have little or no production. Frac sand is needed to “prop open” the fractures in the rock reservoirs to allow oil and gas to flow out more freely.According to the U.S. Geological Survey (USGS), the estimated production of frac sand in 2015 was 71 percent of the total production of industrial silica sand or 67.4 Mt (74.3 million st). This is a decrease of about 12 percent from 2014. However, the silica sand industry and other industry sources estimate only 50 Mt (55 million st) of frac sand were produced in 2015. In recent years both the USGS and industry studies have been very close in estimating the production of frac sand but with the recent downturn in frac sand production, perhaps, reporting to the USGS was not as accurate. These discrepancies may be that the USGS statistics are based on voluntary reporting by the industry and some companies report their approximate production, others may not. It is always difficult to obtain accurate production figures of any industrial mineral or construction aggregate operation as most companies tend to keep those figures somewhat confidential. It is certainly accurate to report that the production of frac sand had decreased since the last quarter of 2014 and through 2015. The oversupply of oil and natural gas has led to this decline in frac sand usage. Oversupply has idled drilling rigs and well completion activities. World Oil Magazine reports that 2015 was the worst year for rigs in a quarter century. The only wells being completed are those that have contract agreements to do so, others have been capped. Very few new wells are being drilled. Since about 98 percent of well completion is sand and water, the sand supply has caught up with the demand. There are some bright spots in the “oil patch” as the Permian Basin in Texas and the Woodford Shale in Oklahoma have kept pace somewhat with drilling and completion. It has been reported that the frac sand producers in the Brady-Voca, TX area are producing to nearly capacity. The northern frac sand producers like those in Wisconsin, Illinois and Minnesota are feeling the downturn because of the cost of shipping sand to these moderately active basins and plays. The “rule of thumb” is that freight is 2/3 and sand is 1/3 the cost."

Jul 1, 2016

By Ashis Bhattacherjee, Bijay Mihir Kunar

A literature review on quantitative analysis of mine safety studies revealed that investigators use a wide range of statistical techniques for the analysis of mine injury data. Researchers have addressed the various issues of accident causation and prevention through analysis of mine injury data collected from mines. These studies are generally based on historical accident/injury data without considering the injured person/population at risk. In this paper, a public health approach, based on scientific methods of epidemiology, is presented to address mine safety issues. Epidemiology is the scientific study of disease and injury patterns among populations in time and space. Originally, epidemiology was concerned with epidemics of communicable diseases. Then it was extended to non-communicable diseases. Safety researchers found that epidemiologic methods are the best tools for injury research, because the occurrences of injury and the occurrences of disease are quite similar. As a result, some researchers started applying this concept to injury research. This paper presents some of the techniques used in epidemiologic studies and illustrates the application of a case-control study design to evaluate the role of some risk factors associated with injuries in underground coal mines. In this study, the injured persons were identified and, simultaneously, interviews were conducted to find the significant risk factors responsible for occupational injuries in coal mines.

Jan 1, 2011

By Luttrell. G.

The profitability of coal mining operations is highly dependent on the performance of the coal blending and processing facilities. Many companies have recognized this fact and have instituted optimization programs that require large amounts of coal characterization data, extensive operational information and complex costing models. Unfortunately, this brute force approach to optimization is often overwhelming in terms of time and cost and is generally too inaccurate to be of value in day-to-day field operations. A simpler and more practical approach involves the use of ?micro-price? optimization throughout the coal supply chain. This fundamental concept assigns unit values to each type product (particle or groups of particles) passing through the production units. True optimization occurs whenever all particles with positive worth are recovered and passed to market, while all particles with negative worth are rejected. This paper describes the fundamental workings of the micro-price concept as applied to coal blending and processing operations. Several examples are also included to demonstrate the economic gains that can be realized via the application of this concept.

Feb 23, 2014

By Theodore J. Williams

Computer control has been one of the fastest moving and most glamorous fields of industrial development in the past decade. A review of this period shows some truly remarkable accomplishments in both system development and applications. In addition, work now under way promises results which will continue the rate of progress of the past. This paper will review the history and status of the field of computer control and point out the major breakthroughs which have occurred. It will analyze the present trends and extrapolate them to predict the early future developments in the field.

Jan 1, 1968

By James Wm. White

Today a large number of open pit mines use computer-based mine management systems to automatically assign haul trucks, track equipment, and manage information. Now advances in digital communications allow the use of these systems in underground operations. Underground mine management systems help maximize production by providing impressive gains in areas such as equipment and manpower utilization, draw point equalization in block caving operations, preventive maintenance, and safety. Current systems use allocated or "locked" train and LHD dispatching. While allocated dis-patching rarely optimizes open pit production, it offers an efficient mode of operation underground where options are more limited.

Jan 1, 1996

By Anthony Edey

It is a generally accepted and widely discussed fact that the world in general, and the United States in particular, face a shortage of energy at the present time which will become worse in the future. There is, however, no sign of a similar concensus as to the actions which would prevent or overcome this expected shortage. An immense variety of solutions has, however, been put forward, ranging from the purely political to the outer fringes of sophisticated technology. One resource which surprisingly is often only cursorily included in this discussion is the immense known petroleum reserve lying within the United States. When this subject is discussed, indeed, it is usually in the context of the improvements in production or new discovery rate that could be expected to result from possible politico-economic actions that would raise the real price obtained for domestic crude. This interest in the potential for improved domestic production is undoubtedly justified, but very little attention is normally drawn to the fact that even under the most favorable policy framework the majority of the oil that has been, or will be, discovered will remain in the ground due to the inherent limitations of production through surface wells.

Jan 1, 1979

By Steve Kral

Commodity price down cycles are a fact of life in the mining industry. And companies pre-pare for them as best they can. Evenso, operations are still curtailed or closed during those cycles, profits shrink, layoffs are inevitable and many companies do not survive. However, one of the few good things that occurs during down cycles is the new, innovative exploration, mining and processing technologies that come about during hard times. To survive the lean times, the mining industry turns to improved technology to decrease costs and hold the bottom line. And, because mining is a cyclical business, each down cycle brings about technology improvements that carry over into the good times.

Jan 1, 2004