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By M. Z. Mubarok, Z. T. Ichlas, A. T. Sugiarto, K. Sukamto

The use of ozone as an oxidant for the direct leaching of zinc sulfide (sphalerite) concentrate in sulfuric acid medium under atmospheric pressure was explored. The influence of acid concentration, feed gas injection rate, particle size distribution, stirring speed, temperature and slurry density on zinc extraction efficiency was examined. The experimental results showed that the leaching efficiency depends on all of these operating parameters except for stirring speed. It was found that essentially complete dissolution of zinc from the concentrate with the present method can be achieved in only about seven hours under the conditions of sulfuric acid concentration of 2 mol/L, particle size smaller than 74 µm, slurry density of 50 g/L, stirring speed of 420 rpm and feed gas injection rate of 1 L/min at ambient temperature. The experimental results suggest that the dissolution reactions produce independent elemental sulfur that is readily floated and can be easily separated rather than forming a layer on the surface of the reacted particle, as usually observed in a system with ferric-sulfate as oxidizing agent. It was therefore determined that the dissolved ozone play a key role in improving the rate of zinc dissolution from the concentrate. Analysis of the leaching kinetics indicate that the leaching rate follows the shrinking particle model, and the overall dissolution rate of zinc is controlled by a surface reaction.

By Edward H. Peplow

Mr. Chairman; honored guests; ladies and gentlemen: The subject assigned me today by your committee, according to the program, is "the mineral industry and the public land law I have preferred to title the talk, "you can't mine here", for that is the essence of the message we, as an industry, have been getting from so many agencies of the federal government for so long. And, unfortunately, we can expect to hear the same message even louder and clearer -- with increasing frequency in future, unless. Every segment of the industry devotes the necessary time, energy and creative thought to combat successfully the forces that are writing and broadcasting that message. I said that agencies of the federal government are sending the message --- and this, of course, is true, the forest service, for example, and some bureaus of the department of the interior as well as others have appeared in recent years to be abiding by a policy designed to block mineral entry to as much of the public lands as possible and to wipe out existing mining claims.

Jan 1, 1967

By S. Makni, F. Wang, A. Rosa, B. Klein, C. Saud, R. McIvor, A. Kumar, C. Gagnon, D. Gong

In response to the Natural Resources Canada “Crush It Challenge”, Corem partnered with the University of British Columbia and led a project to develop and demonstrate the use of high-pressure grinding to replace the workhorse of the industry, wet ball milling, with high-pressure grinding. Two plant case studies, a small tonnage gold recovery operation, and a large tonnage copper recovery operation, were carried out. Plant circuit performances were compared to pilot plants operated on the same circuit feed set up to represent the novel equipment and flowsheet that was developed to produce separation circuit feed. Numerous obstacles to industrial implementation of highpressure grinding in this role which were recognized at the outset of the work were successfully addressed. In both cases, comminution equipment energy savings alone, and final stage total circuit energy savings, exceeded 60% and 50%, respectively. Downstream mineral separation performance was the same or better.

Mar 2, 2022

High pressure grinding mills have been successfully introduced in the industry. They offer the possibilities for capacity increase of existing plants and reduction of operating costs. Further metallurgical advantages in gold and copper are possible. The plants in operation are running in different applications and modes of operation. They can be installed in a combination with SAG and ball mills or in a stand-alone mode. In combination with other grinding mills, it has to be investigated how the HPGR can be installed to reach the full efficiency. This paper describes the possibilities to implement high pressure grinding rolls and shows by case studies the potential of savings which could be reached

Jan 1, 1996

By Wayne J. Nordstrom, Dennis L. Murr, James E. Wennen

National Steel Pellet Company (NSPC) conducted pilot scale testing and computer simulation studies which indicates that the capacity of the secondary grinding mill could be increased and that concentrate grade improvement could be expected with improved classification in the grinding circuit. Based on these studies, a decision was made to modify one secondary ball mill line at NSPC to include both cyclone and screen classification with magnetic separation applied to the circulating load. This paper will briefly discuss the studies leading to the decision to modify the circuit, the design of the modified circuit and the initial start-up and operating experience.

Jan 1, 1997

By J. A. Haggman

In a country richly endowed in mineral wealth, Climax Arimco Mining Corporation's (CAMC) Dinkidi porphyry Au?Cu deposit in Nueva Vizcaya province, Philippines, represents the most significant mineral discovery in the country in recent times. The deposit is located within a belt of young intrusive and volcanic rocks in the Sierra Madre mountain chain of north Luzon a region previously unassociated with porphyry-style mineralization. Since 1989, drilling of the Dinkidi deposit has outlined a resource of 124 million tonnes of 1.0 g/t gold and 0.41 % copper. Regional exploration throughout CAMC's 37,000 hectare FTAA has identified a further sixteen potential porphyry-related deposits. A new mining law was passed in March 1995 but prior to that CAMC had the first Financial and Technical Assistance Agreement (FTAA) granted by the Philippine government allowing 100% foreign ownership of mining projects.

Jan 1, 1997

By A. Bascetin

It was recently proposed to use the pastefill technology as a surface tailings management method. Surface paste is an economic and safe storage method that respects current environmental regulations. There are many problems related to accidents that occur in conventional tailings damps. In this study, the applicability of the surface paste disposal (SPD) method for a Pb-Zn mine in western Turkey was examined. Density was 3.084 and specific surface area was 0.899 m2/g. The mill tailings have very low plasticity and show characteristics of clays and silts in terms of the Unified Soil Classification System. The particle size distribution of the tailings was 39.2% particles finer than 20 µm. The results of this study showed that the physical and chemical properties of mill tailings make them suitable for SPD.

Feb 23, 2014

By Ray Brainard, Adriana Ventimiglia, Amanda Kerr

The $2 billion Horizon Lateral includes over 30 miles of trenched and tunneled pipeline with diameters up to 120 inches.Related infrastructure includes large and small pumping stations, reservoirs, and flow control facilities. This paper will discuss the strategy and processes used to determine contract packaging and contracting delivery methods for the various project elements with an emphasis on the tunnels and trenchless crossings. Prior Authority experience and the rigorous risk-based approach to develop the preferred alignments played a large role in determining the outcomes along with schedule concerns and permitting and easement acquisition.

Jun 13, 2023

By R. R. Kallu

The current 120 psi seal design and evaluation practices are mostly based on simple analytical solutions. Considering the simplistic assumptions and limitations involved in simple analytical solutions and practical difficulties involved in conducting conventional full-scale explosion tests for evaluating 120 psi seal designs, there is a need for developing new scientific methods and engineering practices for design, analysis and evaluation of mine seals.

Jan 1, 2010

By Kenneth K. Landes

So far my consulting in industrial minerals has been confined principally to carbonate rocks,-salt, coking coal, and glass sand. Much of this work has been for companies either too small for a full-time geological staff or unaware of the value of employing one or more qualified geologists permanently. It gave me considerable personal satisfaction to see several of the latter companies employ one or two full-time geologists after the completion of a consulting contract with them. One possible reason why some companies lack the wisdom to hire geologists is that they are dominated by engineers who still subscribe to the old idea that engineers are self-sufficient in all fields. They could have learned this from their professors. I once knew a Dean of Engineering who got purple in the face when a faculty committee was discussing the financing of a broad gauged engineering project and suggestions were made that assistance be obtained from the Schools of Business and Law and from some of the science departments tie pounded the table and shouted "Engineers are trained to handle all this!" In teaching engineering geology some years ago I used to tell the class repeatedly that the course would not make them geologists, that the purpose was to teach them

Jan 1, 1972

By J. Kretschmann

"By the end of the 1950s, the German hard coal mining industry produced 150 million tons of hard coal per year in 170 collieries with 600,000 employees. At that time, 70% of the primary energy demand of the Federal Republic of Germany was covered by domestic coal. However, due to coal mining becoming an increasingly globalized business and the oil and gas industry producing with lower costs, the German domestic hard coal industry stood constantly under restructur-ing pressure. The industry declined until the end of its life cycle. In 2007, a political understanding was arranged to phase out German hard coal mining in a socially acceptable manner by the end of 2018. This decision required a new strategy for the coal mining industry. Being strictly finalized, the German hard coal mining industry has to be prepared for the post-mining era. To create a sustainable development strategy, the long-term impacts of coal mining activities in Germany concerning the environmental, economic and social dimensions will be analyzed systematically and forward-looking. The regional and social responsibility during the closing process and for the post-mining era will be emphasized. High technical standards in environmental protec-tion and post-mining technologies, as well as long term experiences in the development of former mine sites to create new jobs are significant from an international point of view. The traditionally constructive social partnership between employers, union, and employees has enabled long-term stable adaption processes and avoided social friction. The sustainability strategy of the German hard coal mining industry can be regarded as a role model for other mining countries and regions facing similar transition challenges. INTRODUCTION Principally, mining is a finite business that reaches its end if the deposits are depleted or the raw materials can no longer be mined in an economically profitable way. However, the impact of mining is po-tentially an infinite one – at least if you measure it at a human time scale. Mining always means interfering with geological and ecological structures that cannot be reversed to their original condition. In general, the mining cycle (Figure 1) can be divided into three phases: 1. The exploration phase, in which the deposit is investigated to determine its technical and economic profitability. The period of these undertakings is relatively short and can lead to the launch of mining operations. 2. What follows is the actual mining phase which usually lasts for a long time and ends latest when all deposits are fully depleted. This lifespan may be shortened if the economic conditions (production cost or market price) deteriorate. Nevertheless, mining may be resumed if those conditions become favorable once more (examples are silver mining in Germany or rare earths mining in the USA). 3. The longest phase, however, is the post-mining phase as the human interference into geology and nature is usually inten-sive and irreversible. Mining can lead to consequences which have a permanently adverse impact on people and the environment; therefore, they have to be managed as best we can (1)."

Jan 1, 2017

By Roger L. Hulette

Mt. Newman Mining Co. is now completing an expansion program, begun even before initial construction was complete, which will result in facilities with the ability to ship over 30 million tons of iron ore per year by early 1973. Confidence in such rapid future growth was evidenced by careful planning for the future expansion of those facilities provided for initial operation of the project which first shipped ore on 1 April 1969. Ore sales contracts totaling more than 300 million tons have been negotiated, thus justifying the optimism which led the joint venturers to provide over $200 million in initial investment and a like amount in capital required to finance the continuing expansion program. Members of the Mt. Newman Joint Venture are: Amax Iron Ore Corporation - 25% (a subsidiary of American Metals Climax) Pilbara Iron Ltd. - 30% (a subsidiary of Colonial Sugar Refining) Dampier Mining Ltd. - 30% (a subsidiary of Broken Hill Proprietary) Seltrust Iron Ore Ltd. - 5% (a subsidiary of Selection Trust Ltd. of London) ? Mitsui C. Itoh Iron Ore Pty. Ltd. - 10% Mt. Newman Mining Co. Pty. Ltd. manages the project on behalf of the five companies which make up the joint venture.

Jan 1, 1972

By Robert J. Gorney

This paper deals with the actual application of a direct digital control to simple as well as complex industrial process control loops, Fundamental descriptions of preliminary research and design are described briefly, as is the development of the present day controller and control computer. The results and effects of direct digital control in various types of single and cascaded loops as opposed to the use of conventional controls are discussed. Computer supervision of a process and control override are taken into account, in addition to methods of short and long term plant economic optimization.

Jan 1, 1965

By Ashish Ranjan Kumar, Steven Schafrik, Oscar Velasquez

Flooded-bed dust scrubbers installed on continuous miners use fibrous type multi-layered filters to capture dust from the airstream. Prolonged operations of the scrubber could lead to filter clogging due to dust accumulation. This results in reduced flow through the scrubber and elevated dust levels in the mine environment. This paper compares the performance of a conventional fibrous screen filter and a novel impingement type dust filter. The impingement filter is a self-cleaning system and was designed to have a resistance similar to the fibrous filter. The cleaning efficiencies for these filters were computed using iso-kinetic sampling and optical counting of coal dust particles in a clean unclogged state. The cleaning efficiency of the impingement filter also increased with an increase in particle size and was comparable with the conventional fibrous filter. The cleaning efficiency of the fibrous filter improved significantly with an increase in water flow. The non-clogging nature of the impingement filter and minimal maintenance requirement makes it an attractive alternative to the conventional fibrous type filter in mining applications. The research also proposes a term called ‘filter performance factor’ to compare the performance of different filters under similar operating conditions.

Sep 19, 2020

By H. B. Weaver

The development of a method to manufacture diamonds has been rated as one of the out- standing scientific achievements of our time. The story is both interesting and significant. This paper will quickly review history of diamond and manufactured diamond. Next, it will discuss manufactured diamond as a product -- how good is it -- and what is the significance of this scientific achievement. And finally, present a few thoughts about the future of this technology and this product. For centuries, diamond was found only in alluvial deposits, primarily in the Golconda fields of India. As a result, man knew nothing of the process by which the stones were formed. In 1860, diamonds were found in South Africa under completely different conditions. Here, for the first time, they were found in volcanic pipe -- their mother ground. These volcanic pipes are roughly cylindrical columns of rock which go deep within the earth. The theory as to the formation of diamond was presented by the geologists in that era. The theory states that molten rock was thrust up through a layer of carbonaceous shale where it picked up the carbon necessary for diamond formation. It was generally agreed that diamond was formed approximately 240 miles below the surface of the earth, thus indicating that extremely high temperatures and pressures were involved.

Jan 1, 1964

By Ma Lianren, Wang Duolun, Chenzhe Li, Hongyan Xie, Fenglan Luo, Huixin Jin

In this study, the oxidation of low-grade pyrolusite to potassium manganate in alkaline solutions under O2 pressure has been investigated. The effects of different conditions on the high-grade and low-grade pyrolusite leaching process were investigated based on thermodynamic calculation, as well as the reaction mechanisms and kinetics of the low-grade pyrolusite during the leaching process. The results showed that the manganese conversion rates of the two types of pyrolusite were almost the same, and reaching 99% for high-grade pyrolusite and 96% for low-grade pyrolusite under optimal conditions. The optimum condition for low-grade pyrolusite sample JM-2 was achieved as 0.5 MPa of the oxygen partial pressure, 55% of KOH, 14 of the initial alkali-manganese ratio, and ≤ 48 μm of the mineral granularity at 260 °C within 150 min of leaching time and 500 rpm. In alkaline leaching of low-grade pyrolusite, Mn(IV) was oxidized into Mn(VI). The particles changed from large particles to flakes and finally formed crystals. Finally, the shrinking core model was used to fully describe the leaching kinetics of the manganese. It was demonstrated that the leaching of manganese was controlled by the chemical surface reactions and the activation energy which equals 115.9121 kJ/mol.

Dec 3, 2022

By Jesse H. Auvil

In January of 1966, during the annual session of Georgia's General Assembly, Representative Paul E. Nessmith of Statesboro, Georgia, walked into my office and asked me what I thought of the advisability and feasibility of a law which would require the mining operators to reclaim their mined out lands. My answer to him was, as a one time mine superintendent and operator, that I probably would not think very highly of the added cost which reclamation would impose on the operation; but that since assuming the job of Chief Geologist and Assistant Director of the Georgia Department of Mines, Mining and Geology, and in retrospect, I could recommend it very highly, particularly in view of the increased pressure being applied by the Federal government along these lines. I stated then and still emphatically state that this sort of administration should be done on the State level rather than the Federal level. He asked me if I would conduct him on a tour through some of the mining country in which I had worked and to this I readily agreed. The result of this trip was that he was adversely impressed by the devastation which the mining operations had wreaked on that area of middle Georgia along the fall line known as the kaolin belt. Very little except talk was done for the remainder of 1966.

Jan 1, 1970

By R. A. Seitz

This paper presents a framework for analyzing the theory and industrial practice of coal flotation and gives some examples of its use for understanding flotation phenomena and optimizing/controlling flotation circuit performance. It is based on extensive laboratory and in plant test work conducted over the past several years by researchers at MTU as well as an analysis of the literature. Previous researchers have usually considered either the surface chemistry or the kinetics of coal flotation behavior, only rarely have these factors been considered together. However, these factors must be considered together in order to gain a clear understanding of the theory underlying coal flotation such that its practical application can be optimized. Fortunately, this complex objective can be achieved by considering the recovery and rate of recovery of the different types of particles present in the feed to coal flotation circuits and the fundamental mechanisms responsible for these recovery phenomena. The influence of three major groups of variables must be considered: control variables (reagent additions, aeration rate, etc.); disturbance variables (feed pH, percent solids, etc.); and circuit design variables (number of cells, circuit arrangement, etc.). Each of these groups of variables affects process kinetics in a clearly understandable manner, which, once determined, is extremely useful in circuit design and optimization. This paper includes a discussion of the use of the proposed framework to explain the effects of some coal characteristics on flotation performance. In addition, an example of using this analysis to optimize the performance of a coal flotation circuit using frother and collector addition levels is included.

Jan 1, 1985

By Francis Martino

There are numerous techniques and predictive models used by geologists and mining engineers to define coal reserves and plan mines. The traditional reserve estimation methods commonly used include the isopach, triangular, polygonal, inverse-distance weighting, weighted-moving-average, and trend-surface methods. Geostatistically-based estimation techniques are now being examined by many geologists and mine planners as a superior alternative to these traditional methods. With today's coal mine development costs often exceeding $100 million, and power generation $1 billion, it is logical that a technique that can indicate the degree of confidence associated with a reserve estimate (fuel supply), and thus also the degree of risk, is highly desirable to the coal producer, the financiers, and those desiring to commit to coal utilization under short or long-term supply arrangements.

Jan 1, 1983

By Lewis L. Oriard

The authors outline the development and application of blasting methods put into use 11 years ago at the Berkeley Open-Pit Mine, Butte, Montana. The blast design uses a very short delay (5 milliseconds) between detonation of explosives charges, a feature challenged several times in principle despite its success for Anaconda. Concern is expressed over the categorical rejection of very short delay blasting which can make the difference between success and failure of major mining operations. There is ample evidence to show that the method can be used successfully and not violate the concerns of the public.

Jan 1, 1980