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By Boyd Eisenbraun, Dennis Murr, Milton Rojas

Approximately since 1925, the phenomena of grinding and classification of minerals with screens have been studied. In the U.S. iron ore mining operations located in the so-called “Mesabi Iron range,” magnetite processing plants have made progress in the application of high-frequency screens that have allowed them to process low-grade Taconite ores and successfully achieve the economic benefit of these minerals. In the particular case of magnetite minerals disseminated in the siliceous matrix, the main objective is to reduce the generation of particles called “middlings” with high silica contents. Commonly the primary challenge of the metallurgical task is to achieve high recoveries and iron concentrates with low impurities. To achieve this, several studies and industrial applications have shown success in this regard and not only in iron ores, but also in other minerals around the world. The study described in this paper attempts to describe some key aspects that helped develop an effective solution and list the benefits associated with this modern process design by using industry-proven technologies for minerals in Chile that have similar characteristics to the minerals of the iron belt in the United States.

Feb 1, 2025

By O. F. Brown

The use of quality materials (aggregates and asphalt binder) in optimal proportions is the key to producing optimally performing hot mix asphalt (HMA). The Superpave mix design standard in the US introduced specific volumetric and binder property requirements in HMA design. Different methods for HMA constituent proportioning have been proposed in various guidelines. The design process to determine the HMA blend is currently iterative and engineers rely almost exclusively on experience. This approach is time consuming and often does not result in cost-optimal HMA mixtures. This paper introduces a mixed integer linear programming (MILP) optimization model for hot-mix asphalt constituent proportioning. The MILP model minimizes the total mix cost while satisfying all the volumetric, binder and mix property specification requirements. The model has been successfully validated with real-life example. The aggregates and binder ratios from the model were in close agreement with those from the contractor. The Bailey ratios and the gradation constraints were also satisfied. The cost of the optimal mix was $0.804/Mg less than that of the contractors?. This marginal reduction might make all the difference in an industry that is highly competitive. The MILP model also demonstrated that adding RAP to the contractor?s design would reduce the cost of the blend by $5.74/Mg. The virgin binder content was reduced by 1% because of the recycled asphalt contained in the RAP. This work represents the first successful attempt in incorporating both aggregate and asphalt performance requirements into the optimization formulation. Applying these models will ensure the minimum cost mix that meets all constraints and will increase profit margins for plant operators.

Jan 1, 2012

By Yao Zhou

Under the United Nations Convention on the Law of the Sea (UNCLOS), the international seabed area (Area) and its resources are the common heritage of humanity (CHH). Patent rights can be incompatible with the CHH doctrine and its underlying principles because patent holders might charge unjustifiably high prices to license patented technology for exploring and exploiting the Area’s resources (creating a "patent holdup" situation), might choose not to license, or might license exclusively when doing so would contravene CHH principles. However, a reasonable patent licensing regime can contribute to sharing the benefits derived from the Area and promote environmental sustainability. Provisions of the UNCLOS that stipulated compulsory technology and financial transfers were removed in the 1994 Agreement relating to the Implementation of Part XI of the UNCLOS but to promote equity and sustainability I propose a voluntary licensing regime modeled on the concept of reasonable and non-discriminatory patent licensing that has been used in other contexts. The International Seabed Authority or another entity will need to coordinate and promote this licensing regime through governance of intellectual property derived from the Area. This proposed approach can better effectuate the CHH doctrine and its underlying principles.

Sep 1, 2014

By Alexander E. McHugh

A study of some variables affecting the recovery of molybdenum from oxidized molybdenum minerals was made. The effects of variations in contact time, temperature, pulp density, particle size, and solvent concentration on the recovery of molybdenum using acid and alkaline solvents were investigated. Chemical analyses, screen analyses and microscopic examinations were made and the presence of important elements determined. A hydrometallurgical method was developed to recover the molybdenum from the oxidized molybdenum ore by simultaneous dissolution of the molybdenum with sulfuric acid, adsorption on activated charcoal and flotation of the charcoal. The molybdenum was extracted from the activated charcoal with sodium hydroxide, precipitated with calcium hydroxide as calcium molybdate and this regenerated sodium hydroxide for additional stripping. A solvent extraction method, using mines, was also studied to recover molybdenum from both alkaline and acid molybdenum solutions. Satisfactory results were obtained.

Jan 1, 1967

By Hongjie Yang

The No. 10 metro line of Shanghai city is 36 kilometers in length and will pass through the operating airport runway by using tunnel boring machine with earth pres-sure balance mode. Although there are examples through world that tunnels pass through airport runway and tunnelling underground is not a difficult undertaking technically, there is rare experience in China for the similar projects especially in Shanghai saturated soft soil region. Shanghai soft earth is famous for its high compressibility, high rate of water content, weakness in strength, large deformation and different characteristics in earth strata. Besides, the whole construction process will be under ultra-large airplane dynamic load on the surface ground over the tunnel, which increases the risks of construction process. This paper evaluates the feasibility of building the metro tunnel under such an extremely serious condition, especially the subsidence of ground surface caused by advancing of tunnel boring machine, which also is the most important control target for the safe operating of the runway. Furthermore, this paper discusses the effective measures to keep the settlements in the permissible level during the whole working period for the tunnel from aspects of plan, design and construction.

By Paul Soros

The Conneaut, Ohio, terminal of the Bessemer & Lake Erie Railroad was the first rail-to-ground-to-water coal terminal on the Great Lakes. Compared to the traditional method of holding coal in railroad cars at the ports for dumping their contents into vessels, it provided for: a. Immediate train turn-around independently of vessel arrivals. b. Winter storage of coal at the port, permitting year round shipment by the mines and year round operation of the railroad.

Jan 1, 1969

By Wang Ding-heng, Wang Zhi-yuan, Nolan B. Aughenbaugh

The People's Republic of China has abundant coal resources with proven reserves amounting to 582 Gt (641 billion st). Recognizing coal as a major energy source on which to build the country's industrial and economic base, there has been a rapid increase in production since the founding of the People's Republic. In 1949, only 29.4 Mt (32.4 million st) of coal was mined. Production has increased to 576.5 Mt (635.5 million st), exclusive of Taiwan, at present, making China the third largest coal producing country in the world. Plans call for a 4-5% increase in annual production for the next 20 years. Coal constitutes 70% of the primary energy consumption in China. The remaining 30% is divided between petroleum and natural gas with 26% and hydropower with 4%. Coal use and consumption is divided as follows. General industrial use comprised 48.9%, power generation uses 20.1%, and coking accounts for 10.5% (6.3% for metallurgy and 4.2% for chemical industry). Domestic use such as home heating and cooking makes up 17.8% and coal-fired steam engines for railways uses 4.7%. Coal Districts Coal underlies about 1/18 of China's land area. It occurs in 30 provinces, autonomous regions, and municipalities. In addition, the western interior region, which has not been explored, may contain sizable reserves. Based on geology, geography, and administration, the coal fields can be grouped into five districts as shown in Fig. 1. The north China district, the heart of the industrial base for the country, has the most extensive and largest deposits of the five districts. This amounts to almost 40% of the country's total reserves. The largest coal basin with proven reserves of 181.4 Gt (200 billion st) and the most exploitable seams is located some 300 km (186 miles) southwest of Beijing (Peking) in Shanxi Province. Centered around Taiyuan, the compound field extends from Datong in the north to Xian in the south. Its western extension is not known fully. The Northwest and Northeast districts contain the second and third largest deposits. The biggest coal field in South China is located in the Sichuan and Guizhou Provinces near Chongqing. At present, it is not known if sizable coal measures exist in the Tibetan district. Coal Types China's coal varies widely both in age and rank. Geologically, coal measures were deposited from the lower Carboniferous (Pennsylvanian of the US) and Permian of late Paleozoic, mainly during the Jurassic of the Mesozoic and peri¬odically throughout the Cenozoic. Collectively, coal from the lower Carboniferous, Permian, and Ju-

Jan 3, 1983

By Nathaniel Arbiter

The question of automation of concentrator operations with computer control is under increasing consideration. Some of the problems involved will be discussed from the viewpoint of the availability of the requisite, detailed knowledge of the unit operations. The justification for full-scale automation of a mill must ultimately be economic--an increase in profitability over and above the cost of instrumentation and development, Potential savings would be in three probable directions: decrease in operating labor costs by substitution of machine control; improved metallurgy through continuous effective control; and decreased operating costs by achieving higher unit capacities and process efficiencies.

Jan 1, 1962

By Fiona M. Doyle Garner

Hydrolytic stripping is the process whereby metal ions in a loaded solvent extractant are hydrolyzed by water, typically at 130°-200°C. Equilibrium hydrolytic stripping tests were done on Versatic 10 solutions of various metals, singly and in mixtures. Single solutions of Fe, Xi, Cu, Mg, and tin precipitated aFe2O3, Ni(OH)2, Cu2O, Mg(OH) 2 and ?Mn203 respectively during hydrolytic stripping. Several mixtures containing iron precipitated magnetic spinel ferrites, MFe20k. No other combinations formed mixed oxides. It is proposed that the mechanisms for hydrolysis and precipitation of iron in loaded Versa- tic solutions are similar to those for iron hydrolysis in aqueous solutions. Infrared spec- troscopy and thin-layer chromatography of mixed iron-nickel Versatic solutions indicated that mixed Fe-Ni carboxylate complexes are present. Magnetic interactions between mixed complexes are thought to be responsible for the homogeneous nucleation of magnetic mixed oxides in preference to single oxides.

Jan 1, 1984

By R. Cook

Knowledge based applications are becoming important to Associated Manganese for efficiently dispatching ore of appropriate grades to customers on time. The G2 expert system shell has been used to develop blending and scheduling applications using a combination of object-oriented rule based, procedural, and heuristic approaches. The blending application, for example uses a heuristic approach for creating blends from thousands of small stacks of manganese ore of various grades and sizes, to meet customer specifications while fully exploiting the available inventory. Data capture and data warehousing have become important issues, and the Internet shows strong potential for distribution of pre-processed information.

Jan 1, 1997

By Bobby Michael (Mike) Roberts, G. M. (Mike) Bernard, Ronald R. Kelly

This paper describes Cananea's successful implementation of the world's first mobile high angle conveyor (MHAC™) to achieve multiple-lift stacking of their primary crushed (2,500 mtph) low-grade ore. The mobile high angle conveyor answered Cananea's needs to stack a second lift, 30-meter high, on their Quebalix I pad. The mobile high angle conveyor is a custom unit that was designed by Terra Nova Technologies (TNT) in conjunction with Continental Conveyor and Equipment Company (CCE's 100th HAC). The stacking system expansion project also includes a rail mounted tripper on the existing overland conveyor and a custom designed "corridor conveyor" to build the corridor for the upper mobile HAC tracks and tail of the existing mobile stacking conveyor. Mexicana de Cananea, part of Grupo Mexico, is a large copper producer in Sonora Mexico and has been in operation continuously for over 100 years.

Jan 1, 2002

By A. Bobet

Design of a new underground laboratory is underway through the auspices of the United States National Science Foundation. The Deep Underground Science and Engineering Laboratory (DUSEL) is scoped to provide a diverse group of researchers with a dedicated underground facility capable of supporting a broad spectrum of fundamental and applied research at depth in the Earth?s crust. Key research partners in the endeavor are physicists, biologists, geoscientists and engineers. Engineers are not only designing the underground facilities, but are also actively involved in developing research initiatives. This paper will introduce the DUSEL engineering research program to the mining community, provide an overview of the site, geology, and laboratory facilities, and describe some key program initiatives. The particular technical challenges and opportunities afforded by the construction of DUSEL and the performance of the integrated science-engineering program will be discussed by reference to a subset of research initiatives that are currently under development: Cavern Design, CO2 Sequestration and Transparent Earth. These research initiatives target the development of new techniques that can support improved subsurface investigation, design and construction procedures. An increased use of the subsurface can actively contribute to the development of new, more sustainable solutions for use in mining and civil engineering practice.

Jan 1, 2011

By Ivan C. Machado

In full autogenous grinding (FAG Mills) the ore itself determines almost exclusively the product size that will be produced, as opposed to conventional steel-media grinding where the product size can be "engineered" by changing media size, feed size, feed rate, classifier cutpoint size, etc. SAG Mills are in the middle of the way, since they offer some room to engineer their product size by properly defining some critical process variables, such as feed size, ball charge and size, mill charge and speed. SAG Mill product P80 values are typically in the range of 500 µm (35 US mesh) to 2000 µm (10 US mesh.) Whenever it is possible to determine an optimum value for the SAG Mill product P80 value (which will be the Ball Mill fresh feed F80 value), the Engineer should define the process variables that will yield a SAG product size as close as possible to the optimum calculated P80 value. In general, a coarser SAG product will draw less power from the SAG Mill and more power from the Ball Mill, and conversely, a finer SAG product will draw more power from the SAG Mill and less power from the Ball Mill. Metal consumption analyses also have to be taken into consideration, for they typically account for 30% to 45% of the total grinding cost. This presentation addresses the issue of defining an optimum SAG Mill product size (X=P80), during the design phase of the SAG and Ball milling circuits, from a general perspective, i.e., the SAG product size that will lead to an overall SAG Mill - Ball Mill optimum performance. Bond's Third Law approach is used, as well as the SPI (SAG Power Index), and also the generally accepted equations and Engineering Practice currently utilized to design SAG Mill

Jan 1, 1999

By P. R. Taylor

A cyclone reactor system for the partial reduction and melting of taconite concentrate fines has been engineered, designed and operated. A non-transferred arc plasma torch was employed as a heat source. Taconite fines, carbon monoxide, and carbon dioxide were fed axially into the reactor, while the plasma gas was introduced tangentially into the cyclone. The average reactor temperature was maintained at above 1673 K (1400 C), and reduction experiments were performed under various conditions. The influence of the following parameters on the reduction of taconite was investigated: carbon monoxide to carbon dioxide inlet feed ratio, carbon monoxide inlet partial pressure, and average reactor temperature. The interactions of the graphite lining with carbon dioxide and taconite were also studied.

Jan 1, 1993

By w. Chruscielewski, T. Domanski

INTRODUCTION Concentration of radon 222Rn and its decay products occuring in the Polish mines of metal-ores call for the necessity of systematic radiation control /Do8la/ both of the working environment and of the miners' personal exposure. The attempts at introducing a system of radiological protection in mines, similar to the ones existing in X-ray or isotope laboratories, took several years and consisted of development of the methods for control of concentration of radon and its progeny in the air, as well as the methods for measuring individual exposure. It was accepted that the assessment of both transient concentration in the air and of personal exposure are basic elements of the control system, which should be implemented independently of each other. Concentration measurement serves to detect and to determine those areas in mines where there is intensive radon emanation, and where current control of the effectiveness of technology introduced to deacrease the concentrations is necessary; personal dosimetry results in the assessment of the actual exposure of miners to radiation. PRINCIPLES OF THE SYSTEM The assessment of working environment is based on concentration measurements of the potential radiation energy of radon alpha decay products. Decentralized assessment is carried out by the special dosimetric service operating in each mine. Dosimetrists are equipped with portable radiometers, type RGR-11, made by the institute of Nuclear Research, Warsaw. The radiometer is presented in Fig. 1. Measurement of filter activity is performed automatically according to Markov's method /Ma62/ or any other method. Simultaneously to potential energy measurement the dosimetrists are measuring the dust concentration in the air and ventilation rate. Ventilation service looks for correlation between those indices and the concentration of radon daughters in the air. Derived Air Concentration /DAC/ for concentration assessment was accepted to be 6.25 10-6 Jm-3 /0.3 WL/ according to ICRP recommendation /Publication No. 24/ /ICRP77/. If environmental measurements reveal potential energy concentration exceeding the value of 0.3 DAC at working places, the miners employed there are subject to individual control of personal exposure. Individual exposure measurement is carried out centrally by the Institute of Occupational Medicine in [Lodz] for all metal-ore mines. Miners who are to be included in the control scheme are referred by a mine management to the Institute where they are registered and assigned a dosimeter. A passive dosimeter with

Jan 1, 1981

By I. Iwasaki

Differential flotation of bulk sulfide concentrates from Duluth gabbro into copper and nickel concentrates could be implemented by first destroying the hydrophobic coating with ozone and then by recovering the copper concentrate with a copper-selective collector. A number of parameters involved in the use of ozone; such as the sequence and the conditioning time of ozone treatment, the pulp pH, and the level of xanthate addition, were investigated.

Jan 1, 1985

By K. Fleck

Energy West Mining Company (EWMC) has implemented a geologic program for improving stability and support requirements along deep two-entry longwall gateroads at its Deer Creek Mine operations located near Huntington, Utah. Together with geotechnical monitoring and concurrent review of mine seismicity in cooperation with MTI staff, it has become possible to improve longwall layout designs for two seam extraction of the Hiawatha and Blind Canyon seams. The geologic program consists of surface and in-mine exploration drilling, surface and in-mine geologic mapping, rock mechanics testing and detailed measurements of changes in depositional and structural conditions during development of every longwall gateroad. The geotechnical program consists of underground measurements at seven locations in two neighboring mining districts located in the Hiawatha and Blind Canyon coal seams under moderate to deep cover. Within the last five years, additional measurements, including data on seismicity and face conditions, have been incorporated into the data collection program for verifying the insitu coal strength and load transfer mechanisms for improving two-seam designs and support systems. Geologic mapping results are also used to predict local stability of headgate and tailgate entries, combining mine roof mapping, stratigraphic profiles of the coal and roof, and depth-of-cover information and dual-seam mine overlays, for use by operations personnel in planning roof and rib support for the retreating longwall sections.

Jan 1, 2012

By William R. Yernberg

The “China & East Asia Mineral and Energy Re-sources Symposium — CEAR 2000” was held Jan. 23-26, 2000 in Denver, CO. Conference sponsors included Resources and Technology Symposia of Colorado and the Asian Journal of Mining. The meeting was attended by representatives from China, Japan, Mongolia, Korea, eastern Russia (Siberia) and the United States. The US attendees consisted of interested parties from mining and energy companies, financial institutions, consultants and government agencies. In his opening statements, L. Maness, Jr., president of Resources and Technology Symposia of Colorado, said that the “goal of the conference was to make jobs and friendships and to introduce people to each other.” The conference provided an opportunity for Western mining interests, including mining companies and investors, to meet with government agencies from both sides of the Pacific.

Jan 1, 2000

By Robert E. Goodwin

As man's need for minerals continues to grow and as the known mineral deposits become depleted, it may be expected that these increased demands will result in greater exploration for additional deposits and at continually increasing depths below the earth's surface. As labor and material costs continue to rise, the need for more economic material handling will be emphasized. The quest for heavier payloads, safely moved at faster speeds from deeper mines, will be vigorously pursued. Strenuous efforts are, therefore, being made in the wire rope industry to develop ropes with greater strength-to-weight ratios than presently available while maintaining the dependability and long life being received from the conventional rope manufactured today. For many years, high quality rope wire has been manufactured from rods of selected steel compositions. Carefully-controlled wire drawing combined with proper heat treatment has resulted in high quality wire and wire rope throughout this period. Refinements in the rod produced from specially-selected high carbon steels combined with the latest improvements in wire drawing and heat treatments have made it possible to manufacture higher strength rope wire of uniform composition and structure that is suitable for use in Special High Strength wire rope.

Jan 1, 1970

By J. C. Willett, J. R. Sanfilipo, P. D. Warwick

The U.S. Geological Survey has conducted an assessment of the Nation’s coal deposits that potentially could be mined during the next 30 or more years. For the Gulf Coastal Plain region, the assessment includes reviews of the stratigraphy, coal quality and resources, and coalbed methane potential of the Cretaceous, Paleocene, and Eocene coal deposits in the region. The results of these efforts are a series of digital maps, text, and tables published in CD-ROM format. Although abundant coal resources are available in the Gulf Coast region, coal quality issues may limit large-scale development in the future. Additional data are required to better evaluate the coalbed methane resource potential for the Gulf Coast region.

Jan 1, 2001