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By H Leonard Mangum, Victor C. Bryan, Dan McCutchen

Recently there has been an unprecedented marketing effort to promote the advantages of various non-electric initiation systems. This activity has probably been influenced by a major manufacturer's decision to discontinue electric detonator production. Subsequently, distributors of explosive materials, rather than introducing new electric detonator brands, are emphasizing the use of existing non-electric systems. In many cases, such methods fill the need of explosive users in the quarry industry. However, the use of any initiation system should be based on performance, rather than the bent of the market or convenience to the supplier. This analysis is an evaluation of the performance of non-electric systems with emphasis on double trunk line and loop (redundant), as compared to precise electric detonators in use by Martin Marietta. Redundant non-electric detonators, even though more costly, offer the most reliable method of non-electric initiation. However, state-of-the-art precise electric detonators give the best overall performance, except in an environment involving extraneous electricity.

Jan 1, 1990

ENGINEERS AVAILABLE (Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members) Graduate mining and metallurgical engineer now open for engagement. Member, 38 years old, married, 19 years' experience in United States, Europe, South America, Africa, in exploration work, surveying, assaying, mining, milling, ore-dressing, construction and management. Four languages mastered. No. 355. Member, aged 35, technical graduate, desires position -as superintendent or assistant superintendent of spelter or zinc oxide furnaces, or both. Gas producer experience, zinc metallurgical and laboratory experience. Can handle men. No. 356. Member, also Assoc. Mem. Am. Soc. of C. E.; excellent technical education, and best of references covering twelve years in responsible charge of work; experienced in surveys, construction, prospecting, mine examination and development and irrigation work; speak Spanish fluently, and can write a good report. Good executive. Available during June. Age 34; married. No. 357.

Jan 6, 1917

By J. A. L. Napier

An analytical solution to the best choice of cutoff grade for a mine is deduced for an assumed model of selective mining. It is found that this choice is determined by the constancy of a special function, the Hamiltonian, over the life of the mine. It is suggested that the appropriate constant value for this function should be determined by the expected long-term average of the paylimit. In that case, the optimum profile can be calculated at each point in time according to the prevailing working cost and product price. In particular, a decision can be made between operation at the true paylimit or at the subsidized paylimit implied by either the lease and tax formulas or the assistance formula for gold mines. It is also shown how the basic formulation can be extended for 'use in the determination of the optimum joint paylimit for two products over the life of the mine.

Jan 1, 1983

By John V. Beall

Dear J. B.: The recent cable I sent you for a transfer of $200,000 was the outcome of the diligence and perspicacity of our group which, as you know, is laboring under severe hardships here in Rondônia. I only mention the latter difficulties in passing because no reply has been received to our urgent appeal for money. As much as I detest appearing to plead for more attention than you feel called upon to pay to our forgotten mission, I can assure you that it would be in the best interest of the company for you to do so. The fact is, we have been able to outmaneuver the competition and have succeeded in securing pesquizas on some of the most promising cassiterite gravels. We have not been able, up to now, to do much bulk sampling (for lack of funds) but our preliminary panning shows great promise as you can see from the enclosed assay sheets.

Jan 1, 1971

By Lynch A. J

The success of the Australian mining industry depends on the quality of its skills. High quality skills supported by a culture which demands success lead to innovations, good practices and prosperity. Average skills lead inevitably to mediocrity. Universities play an essential role in the development and use of skills but the crucial industry-university links have been subordinated to conventional academic interests in training mining and processing engineers. It is only in the area of post-graduate research degrees which are oriented towards the mineral industry that Australia can claim world leadership. Deficiencies are not due to lack of training resources, they are due to inadequate utilisation of the resources that are available. Australia can and should have the world's best mineral engineering school, with a branch in Asia where many of its customers are and close ties with South America where some of its production operations will be. Some steps which might be taken to achieve this are proposed.

Jan 1, 1995

By L. S. Castleman, R. Resnick

The self-diffusion coefficient of columbium has been measured over the temperature range 1535o to 2120°C, using the radioactive isotope Nb95 as the tracer. The data for the temperature dependence of the self-diffusion coefficient are best fitted by the equation D = (12.4 ± 0.8) exp [(-105,000 ± 3000)/RT] cm2/sec. THE increasing need for high-temperature structural materials has stimulated considerable interest in the properties of columbium, since it is a strong, ductile metal with a high melting point—in the vicin- ity of 2450oc.l One fundamental property which has not heretofore been measured is the self-diffusion coefficient. The self-diffusion coefficient plays an important role in theories of oxidatioq2 creep,' sintering4 and other phenomena. Accordingly, the investigation reported in this paper was undertaken to determine the value of the self-diffusion coefficient and its temperature dependence by the use of Mb95.

Jan 1, 1961

By R. H. Migliaccio, M. B. Kahle

The railroad haulage system was started at Kennecott's Bingham Mine in 1906 and has remained a prime mover of ore and waste for the succeeding sixty years. As the stripping ratios increased contract stripping on the upper levels of the mine was introduced employing truck and shovel methods. The ore production then was 90,000 tpd. Analysis of expanding the ore production to 108,000 tpd revealed that the increased ore production and continually rising stripping ratio would result in waste production requirements that exceeded the capacity of the rail haulage system above 6290 level. The advent of larger haulage trucks (65-100 tons) in the early 1960's made available to the Bing- ham Mine economic and operating factors which showed truck haul- age to be the best replacement for rail haulage on the upper levels of the mine. As part of that analysis it was concluded that company stripping would replace the contractor stripping in the top area of the mine.

Jan 7, 1973

By O. W. Walvoord

ONE particular plant has been chosen to illustrate the various factors in mill design. The problems are general in nature and with various modifications are met in the design of most milling plants. Literature on modern mill design is not extensive and certainly has not kept pace with the rapid advancement in the art of ore beneficiation. Much remains to be investigated, and continued vigilance is required to give the operator and the metallurgist the best layout to meet the industry's changing requirements. The Humboldt project, a joint venture of the Cleveland-Cliffs Iron Co. and the Ford Motor Co., involves an iron ore flotation plant near the town of Humboldt, on the Marquette range of the Michigan Upper Peninsula. A crushing plant, designed for an ultimate capacity of 720 long tons per hr, is followed by a first mill unit of 70 long tons per hr. Future mill units are planned to bring the total mill capacity to 5000 long tons per 24 hr.

Jan 1, 1954

By Gordon S. Thomas

The problem of how best to exploit a reserve has vexed mine planners and design engineers since mining began. The cyclic nature of the mine design-scheduling problem, combined with the lack of good mathematical tools for tackling it, have ensured that it has been, and will continue to be, a major challenge for operations researchers working in mining. This paper reviews the current state of the art in pit optimisation and scheduling algorithms. Starting from the inception of the first block models in the late 1950's, it progresses through the developments and applications of the Moving Cone algorithm, the Lerchs Grossmann 3D Graph Theory algorithm and some of the heuristics, to the new artificial intelligence techniques that are being applied today. Along the way, it discusses the limitations of the various approaches and lays the foundations for the research that is currently being undertaken by CSIRO and others in the field of mine production scheduling and control.

Jan 1, 1996

By S. Khoshjavan

In this investigation, the effects of different coal chemical properties were studied to estimate the coal Hardgrove Grindability Index (HGI) values index. An artificial neural network (ANN) method for 300 data-sets was used for evaluating the HGI values. Ten input parameters were used, and the outputs of the models were compared in order to select the best model for this study. A threelayer ANN was found to be optimum with architecture of five neurons in each of the first and second hidden layers, and one neuron in the output layer. The correlation coefficients (R2) for the training and test data were 0.962 and 0.82 respectively. Sensitivity analysis showed that volatile material, carbon, hydrogen, Btu, nitrogen, and fixed carbon (all on a dry basis) have the greatest effect on HGI, and moisture, oxygen (dry), ash (dry), and total sulphur (dry) the least effect. Keywords coal chemical properties, Hardgrove Grindability Index, artificial neural network, back-propagation neural network.

Jun 1, 2013

By Zainelabdin Khalid Zainelabdin Elfaki

The influence of partially replacing cement with marble waste on the workability and compressive strength of concrete bricks was investigated. Three replacement percentages, 10%, 20% and 30% weight marble waste, were used with different curing times of 7, 14 and 28 days. Two specimens were prepared for each percentage and curing time. For this study, marble powder from the Mining House Company in Saudi Arabia was used. It was observed that the replacement of cement in Concrete brick with marble waste enhanced the loading strength and the workability of the prepared concrete bricks. It was also observed that 20% replacement of cement with marble waste was the best replacement percentage compared to the other replacement percentages tested. Marble waste from manufacturing companies, either in powder, sludge or slab form, has negative impacts on the environment. In contrast, reusing marble waste has both economic benefits (i.e., selling the marble waste) and lessening the need for raw resources.

Jan 1, 2014

By Kerry Burns

Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods have been introduced to deal with the problem, ranging from subsidence insurance to site restitution. In planning insurance or restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Only one model is known, which was developed for the Bureau of Mines by GAI Consultants of Monroeville (l,2,3). The GAI model is presented in qualitative terms. This report develops a formal basis for the model and tests a numerical implementation on one of the best-described study areas, Allleqheny County in Pennsylvania.

Jan 1, 1982

In the plumbing of vertical shafts the methods employed and equipment used, are generally made to best suit existing conditions. Undoubtedly, there is no method that can be called standard or that can be used with equal ease and success on all shafts. At the Mount Isa Mines Limited property in Northern Queensland, Australia, local conditions have presented no major difficulties to be overcome in shaft plumbing work. In fact, compared to those at many shafts, the problem has been rather simple. There are three vertical shafts connecting main mine workings, with the greatest plumbing depth for any single lift, 350 ft.Other conditions pertaining to plumbing work have been generally normal.The method we have employed is, in principle, similar to the Weisbach orientation method with a variation that does not necessitate damping of the wires to bring them to rest. Although conditions encountered have not been such that damping the wires would have been inconvenient, we feel we have saved much time and eliminated unnecessary...

Jan 1, 1940

By R. E. Cook

"Mineral deposits require substantial amounts of energy to transport and be processed into usable form and, as such, present a real processing challenge in that the deposits are never homogeneous and orebody compositional characteristics are all over the map. Extracting the desired mineral(s) from the deposit at sufficient profit margin, despite severe fluctuations in market price, requires process automation architecture capable of supporting an integrated enterprise solution. Such an architecture will encompasses the activities of individuals, process units, process areas, plant level activities, mine management and business planning, and accounting systems. Key to the automation process is the aspect of value generation. This article brings together the various requirements for the automation of a mining enterprise and presents the different aspects of how to obtain value across the entire mining operation.Minerals’ processing sites are historically long lived, with 20-year life-of-mine not uncommon and 75 years not unheard of. Considering that hardware technology advancements are introduced every six months, or less, it is prudent to select process automation systems that adhere to “open” industrial standards versus proprietary based systems. In the minerals processing industry, the key to survival is driving the cost of production per unit volume to the lowest possible level and provide enough profit to sustain operations. Control system architecture and business information technology are rapidly becoming important tools in the quest for productivity. Getting key dynamic business performance information at the right time to the right person or process unit is crucial to successfully achieving corporate goals. The process automation architecture selected must, therefore, be able to integrate to the various networking enterprises and business systems.The mining industry is generally known as an extractive industry that is physically oriented with respect to operations and the activities in which workers engage. Large numbers of people performing manual tasks in difficult surroundings, produce variable outputs. But times are changing – and so are industry best practices. While the nature of work still consists of activities such as ore extraction, ore movement, ore concentration, refinement and logistics, automation innovations are starting to change the nature of many of the production steps. The industry has transitioned from requiring more physical activities by workers to more information management, automated control and collaboration within the operation. Humans are good at situational intervention and nonlinear reasoning and do best when empowered with an overall production perspective. Machines and automation are good at repetitive functions, steady state operation, and managing transitions. Thus, a combination of advanced technology solutions, reliable and useful information and full human contributions are necessary to mining operations for value generation."

Jan 1, 2015

By S Shipard

Filters are used in water treatment and hydrometallurgical process plants for objectives such as generating a dry spadable solid, pumpable high density slurry or high purity filtrate. The priority objective of every polishing filter, sometimes also termed clarifying filters is high purity filtrate and these are found in many diverse industries and even different applications within the same industry.To generate a high purity filtrate, process designers have the choice of many different polishing filter products, but in reality very few polishing filters are based on fundamentally different filtering concepts.This paper reviews the technology merits of well-known and the more recently developed polishing filter products and aims to assist metallurgists and engineers with the selection of an appropriate polishing filtration technology for pregnant liquor filtration and other process applications, plus a guide to best practice.CITATION:Shipard, S, 2013. Polishing filters for mineral processing plants, in Proceedings MetPlant 2013 , pp 118-125 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By A Tsang, D La Rosa, L Julian, W Hunt, R Pratama

Mineral extraction is facing the twin challenges of finite resources and increasing environmental and economic costs. Society’s growth is matched by an increase in demand for the earth’s resources. It is incumbent on us as contemporary mining professionals to promote and facilitate ethical and efficient practices. Technological developments have and will continue to allow a decrease in viable cut-off grades, creating new economic opportunities from deposits that were previously uneconomic. Mining low-grade deposits however, even with perfect recoveries, will have a significant environmental cost for the metal won. The greatest opportunity to increase metal with the least environmental cost is to increase the metal yield from existing mines. The determination of mining polygons is a critical juncture where rock is typically subjected to the binary grading of either ore or waste. This is undertaken using a number of factors, such as the mining equipment being used and the recovery in the processing plant. Traditionally, mining polygons were generated on the in situ grade control model. This ignores the complex differential blast dynamics that occur during blasting. Two opportunities exist to improve metal yields: optimise the blast design to achieve the post-blast muck pile that will support the greatest outcome; and generate optimised polygons on the post-blast muck pile. A data set from a Canadian Gold deposit is used to demonstrate the potential benefit of iterative blast movement modelling and grade control polygon optimisation on metal yield. The impact of blasting on the total recoverable metal is presented, highlighting blast design as a critical process in the mining value chain.

Sep 1, 2024

By Charles Legrand

(San Francisco Meeting, September, 1915) THE problem of mine pumping is so much affected by local conditions, and those conditions are so liable to changes during the life of a mine, that the best system to use is difficult to determine. The experience of the;, writer has been that, in general, for copper mines, electric pumping is most satisfactory unless the quantity of water to be pumped is great or. the mine does not use electric power for any other purpose. As a rule, however, figuring on the cost of necessary power plant, the total cost of: installation is greater with electric pumps than steam- pumps. As the water is liable to be gritty, outside-packed plunger pumps are to be recommended, and if the water is not acid, or only slightly so, chilled cast-iron plungers pay for their extra cost very quickly in diminished cost of packing. With chilled plungers it is possible to use metallic, packing instead of soft packing, if the water, is not too gritty nor the lift too high. In vertical pumps this packing is satisfactory for lifts up to 400 ft., in the experience of the writer; and may be found satisfactory for higher lifts. For water slightly acid, cement-lined pump bodies have given good satisfaction. For acid. water, both plungers and pump bodies should be made of acid-resisting bronze. For high lifts, especially with gritty water, a satisfactory pump valve is difficult to find. To reduce the unbalanced pressure on the valve at time of opening it is advisable to have narrow seats; this, however, brings high pressure on the seats when the valve is closed. On large valves for lifts of 600 to 1,000 ft. we have used leather, hard rubber, vulcanized fiber, and soft brass; for clear water the latter has given best satisfaction. The difficulties due to grit make it advisable to have large sumps where water can settle, and if possible, to have two of them so that they can be cleaned alternately. At the mines of the Old. Dominion Copper Mining ,& Smelting Co.; Globe, it was found that a small air. ejector discharging into a mine car is a very convenient way to clean mud and sand from a sump. .

Jan 9, 1915

By Jack E. Fraley

In this Bureau of Mines study, sealants containing mineral wool, cement, etc, were sprayed through dry-process equipment that propels dry material pneumatically to the water-adding nozzle. Advantages over slurry applications include no mixing, no extensive cleanup, and freedom from hardened cement in equipment should power be lost. Sealants with large mineral wool nodules (>l-inch) were sprayable at rates to 900 square feet per hour for 1/2-inch thickness with little dust and smooth material flow through equipment, but they were weak for mine use, Materials containing small wool nodules (1/4-inch) were stronger but tended to plug lines because the nodules were inadequately separated in the shredder. Increasing the dedusting oil also increased line plugging by holding the nodules together in larger lumps. Best results were obtained using a 3/4-inch-nodule wool with cement binder, which provided both smooth flow through the machine and adequate strength.

Jan 1, 1977

By B. Genc

Safety in South African mines is a subject of significant interest, since many mining companies are experiencing production deficits due to safety-related stoppages. In this paper, safety data from the South African platinum mining sector is analysed for the period 2006 to 2010. The data was obtained from company annual reports as well as the Department of Mineral Resources, and analysis in the study is limited to injury and fatality data only. The overall safety performances of companies in the sector are compared, and opportunities for benchmarking and recognising potential sources of best practice amongst platinum miners are identified. Improving safety usually incurs a cost, and mining companies are particularly conscious of the importance of controlling costs. However, cost considerations often deal only with direct costs, and it has been shown that indirect costs are usually far more significant. Therefore, a greater safety spend will usually result in the creation of value for the mine since it will reduce the indirect costs associated with accidents. The results of some recent research in this area are presented. In this light, where available, the financial performances of mining companies in the sector, obtained from published annual results, are included in the benchmarking exercise to determine whether there is any correlation with safety performance.

Jan 1, 2012

By D. W. Zandee

"IntroductionHaving mined an economic mineral bearing rock which is of insufficient grade to warrant direct smelting, upgrading or beneficiation is required to make it an economically viable ore. The first step in effecting the concentration process is comminution or sequential breaking of the rock to allow liberation and subsequent recovery of the desired mineral particles. Desirably the ore could be broken down to the point where the valuable mineral is completely liberated to maximize the chance of recovering as much of it and in as pure a form as possible. The number of energy intensive stages of breakage required to attain this goal depends on many physical characteristics of the ore such as hardness, friability, toughness, grain size, existing fracture planes and particle shapes.Commonly the distinct stages are primary, secondary and often tertiary crushing and finally grinding. To increase the efficiency of each stage of size reduction, pre-treatment sizing is common.Crusher feed is commonly scalped of large pieces or screened for reduction crushers and classified for secondary grindingcircuits.Although crushing and screening is employed for many different products, this chapter reviews current practice in larger tonnage metalliferous ore treatment plants.Current practice is to use large gyratory or jaw crushers for primary crushing and some sort of gyrating or cone crushers for additional stages of reduction. For autogenous or semiautogenous grinding circuits only the primary crushing stage is necessary, the balance of the work being performed in the grinding stage. For conventional grinding circuits using ball mills or combinations of rod and ball mills, secondary, tertiary and even quaternary crushing stages are normally required.Older type crushers such as stamp mills, double rolls, sledging mills and hammermills are no longer common but are used for small tonnage special processes.Important to efficient crushing are a variety of sizing devices such as grizzlies and vibrating screens. Products at different stages must be stored to give surge capacity and allow controlled feeding rates through mechanical and gravity feeders. These storage piles, bins and feeders as well as crushers and screens are commonly integrated into a total facility by means of conveyor systems. Most often these are endless rubber belts driven by simple or multiple drive mechanisms usually consisting of electric motors and speed reducers."

Jan 1, 1989