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By Christopher R. Winter

Mining companies have sharpened their refocus on their tailings management strategies in recent years. Mining companies with tailings storage facilities that use the upstream construction method have been challenged to track the evolution of industry standards, assess risks, revise design, and communicate design revisions with regulators. While many aspects of best practices and industry standards have evolved in recent years as an attribute of continual improvement, the controlling standard in the design of many upstream dams is understanding the foundational strengths of hydraulically deposited tailings. Following best practices and industry standards, Hibbing Taconite Company managed by Cleveland-Cliffs, began the re-evaluation of foundation strengths underlying a system of upstream dams at the company’s iron ore mine tailings storage facility in northern Minnesota. Initial steps in the re-evaluation require reanalysis of design parameters and recommendations by the Engineer of Record to the Owner, which was followed by a series of meetings with the Technical Review Board to determine an initial path forward. Once a path forward and preliminary design parameters were determined, the Owner engaged with the State Dam Safety Engineer to discuss and seek approval of the plan. With continuous regulatory engagement throughout the process, further refinement of the design parameters for the hydraulically-placed tailings foundations underlying upstream dams began with field and lab geotechnical investigations. Following a review of risk assessments and trigger actions response plans, Hibbing Taconite revised its tailings storage facility operating plans and budget for the coming years. Based on the findings of the re-evaluation, reanalysis, and refinement of parameters, a paradigm shift was realized with the hydraulically placed tailings foundation strengths underlying the upstream system of dams. This paper explores the path that the Hibbing Taconite Company followed to understand the paradigm shift and construct downstream improvements. The plan involved tailings re-characterization, dam design revisions, operating plan reconciliation, budget revisions, wetland permitting, dam safety permit amendments, storm water prevention plans, borrow materials studies, new concrete decant structures and the pursuit to recognize and be consistent with industry standards.

Feb 1, 2024

By C. Menidiatis

The first cement plant of TITAN Cement Co was founded in Elefsis in 1902. It was the first cement industrial facility to operate in the Balkans and in the Eastern Mediterranean region. Currently have four cement plants in Greece producing 5.4 million tons per annum, and 25 ready-mixed concrete sites producing 1.4 million m3 annually. It has a total of 20 quarries, 14 of which are producing materials used in the making of cement while the remaining six produce aggregates used in the production of ready-mixed concrete. All plants in Greece are accredited for ISO 14001. The restoration of quarries began in 1976 at the company?s limestone quarry of the Patras plant, and was soon extended to all quarries. At that time, a department responsible for all environmental issues was established. To date, over 700.000 shrubs and trees have been planted and maintained at quarries, plants and ready-mixed concrete facilities, while over 100,000 trees have been donated to municipalities, communities, customers and to the Greek state.

Jan 1, 2002

By John M. Hird

Texas Gulf Sulphur Company's Lee Creek Mine has opened a major phosphate mining district in the Central Coastal Plains of North Carolina (Fig. 1). The ore deposit as it is now known was roughly outlined in 1961 by a Texas Gulf geologist using wire line exploration methods. Slightly uraniferous phosphate materials were detected by a slim-hole gamma ray probe run in numerous farmers' water wells penetrating the formations. A follow-up-core drilling pro- gram determined the economic ore limits to lie in the south central section of Beaufort County beneath 70 feet to 120 feet of unconsolidated sediments. The 50,000 acre deposit is known to contain over two billion tons of phosphate ore amenable to strip mining methods. A part of the deposit underlies several thousand acres of the Pamlico River estuary. The 90 million dollar capital investment plant built by Texas Gulf during 1965-66 included a strip mining operation using a 72-yard walking dragline, a three million product ton per year flotation concentrator, four fluid bed calciners, a sulphuric acid plant (acid for captive use), a phosphoric acid plant, and three solid fertilizer material plants. Shipment to domestic markets is by rail and truck and to over- seas markets by barge to a transshipment terminal at Morehead City, North Carolina. Early mining investigations were conclusive first that the phosphate ore could economically be recovered only by dry strip mining methods, and second that artesian ground waters in the formation (Castle Hayne limestone) underlying the ore would have to be controlled. This report will relate the application of ground water hydrology in depressurizing the Castle Hayne aquifer to facilitate dry strip mining at depths 130 feet below sea level at the Lee Creek Mine.

Jan 1, 1970

By Rameshwar Sah, PK GHORUI, LR SINGH, SIVALINGARAJU BARISETTY, SHYAM YADAV

Fly ash is a by-product generated by the combustion of coal in thermal power plants. Its disposal is a major environmental concern for these power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, a substantial quantity remains unutilized. Bentonite is commonly used as binder in the micropelletization of process waste to attain the mechanical strength required for handling and transportation. The present paper deals with the partial replacement of bentonite with fly ash in the micropelletization process without affecting the quality of the micropellets. The mechanisms of both the binders are discussed. The bonding of particles by bentonite is a physical mechanism, while fly-ash bonding is a chemical mechanism. Silica and alumina are the major constituents present in fly ash along with lime. In the presence of water, the alumino-silicates and unhydrated lime present in fly ash undergo a pozzolanic reaction and form cementitious bonds, which hold the particles together. Use of fly ash as alternative binder for bentonite has cost benefits besides providing a better utilization option for fly ash.

By Yaxiong Wang, Yong Li, Yuedong Wu, Haigang Dong, Jiachun Zhao

A roasting-leaching process has been developed for concentrating platinum group metals (PGM) from a PGM-containing ferroalloy. The optimized roasting conditions used a NaOH-to-ferroalloy mass ratio of 1.2 at 600 °C for 2 h. The roasted product mainly comprised Na4SiO4, NaFeO2 and Fe2O3. The iron oxide and sodium silicate associated with the roasted product were leached in water and dilute sulfuric acid solution, while the PGM was concentrated in the acid-leached residue. A PGM concentration of 23.4% was obtained with assaying, and the concentration factor of PGM from the ferroalloy to PGM concentration was greater than 9.

Jun 14, 2021

By Stanley O. Reichert

At nuclear facilities, three types of radioactive waste must be managed: (1) high-level liquid waste containing fission products from the chemical separation of irradiated uranium, (2) low-level condensates from the concentration of the high-level waste, and (3) dry solids such as obsolete process equipment, spent ion exchange resins, and irradiated metal scrap. The geological and environmental characteristics of a site are important considerations in planning the waste management program. At the Savannah River Plant, low-level liquids and dry solids are safely and economically placed in the soil where the geologic and hydrologic conditions are favorable. Within the general area where the waste originates, studies are made to locate seepage basins and burial grounds in the most favorable sites: (1) soils should have a high ion exchange capacity and moderate to low permeability, (2) the water table should be deep, and (3) burial sites should be relatively distant from the nearest flowing stream.

Jan 1, 1968

By Christopher Haycocks

The growth of computer and ground control technology in recent years, combined with an urgent demand for low-cost fossil fuels and mineral resources, has set the stage for full-scale utilization of computers in mine planning. Steeply rising production costs and the need to preserve the environment are placing great demands on engineers to improve their mining efficiencies, which can best be accomplished by applying the full capabilities of the computer. Pressure to develop and perfect programs with an immediate potential for improving mine de- sign, reducing mining costs and extending the viable coal reserves of the country has already come to bear in the form of exploding energy requirements, environ- mental considerations and the visible limitations of other energy sources. The computer program discussed in this paper, RAMPLAN (Rock Mechanics Applied to Nine Planning), was constructed as part of a continuing effort at Virginia Polytechnic Institute & State University under the sponsorship of the Office of Coal Research to develop a suite of programs to benefit the mining engineer in improving mine design and evaluation techniques. This program averages out structural data values obtained from randomly placed or gridded point sources across a mining property and uses these values in structural design equations. The basic purpose of the program is to provide accurate estimates of mineable tonnages, based on a realistic assessment of structural conditions existing in the deposit, for use in subsequent evaluation programs. Program output, however, also provides sound engineering data for the mine planner to use in planning and laying out new properties. Mining dimensions produced by the program provide a good starting point for initial layouts; and as more refined procedures are developed for increasing and improving the quality and quantity of information from boreholes, this information may be used with increasing confidence. The rock mechanics principles utilized in the program are generally well-established with full details provided to the user. To produce meaningful results extensive input data, obtained from exploration borehole core data, outcrop sampling points, or mine samples, are required. To assist the engineer, details of the types of tests that should be conducted have been listed. By including all of the ground control equations in the program the otherwise long and tedious calculations can be performed easily and quickly, and the work can provide the basis for a more detailed ground control study. The program is written in Fortran IV Level G to run on an IBM 3701155 ASP and requires 156K storage.

Jan 1, 1973

By Arif Emre Dursun

The aim of this study is to present hazard classifications of location, type and causes of accidents in the Turkish coal-extracting industry using the analytic hierarchy process (AHP). In this study, fatal mine accidents were analyzed by pairwise comparison and weighting, and the most important hazards were identified by determining the effective main and sub-criteria among location, type and causes of accidents. For this purpose, first-, second- and third-level hazards consisting of location, type and causes of accident were determined by using the data of fatal mine accidents in underground and openpit coal mining in Turkey between 2010 and 2020.

May 1, 2024

By William P. Lorenz

Overlying the sulfide mineralization at Anamax Mining Company's Twin Buttes Mine is an oxidized zone up to one hundred meters in thickness. The principal copper minerals in this zone are chryso-colla, tenorite, cuprite, native copper and copper-manganese-iron wad. This ox¬idized zone also contains minor amounts of uranium ranging in concentration from 0.002 to 0.010 percent. Since pit development through 1980, some 38 million tonnes of oxide ore with copper contents greater than 0.6 percent have been brought to the surface. Copper in the oxide ore is extracted at Twin Buttes in, an agitated sulfuric acid leach plant followed by solvent extraction and electrowinning producing 90 tonnes per day of copper cathode. During leaching of the oxide ores small amounts of uranium are solubilized along with the copper values. This is not limited to Twin Buttes as most acidic copper bearing leach solutions throughout the southwestern United States contain small amounts of uranium.1

Jan 1, 1982

By S. Simske, K. Boakye, D. Winters

The application of digitization to operations and logistics is commonplace. From advanced data analytics to intelligent networks, digitization offers tremendous opportunities to create value, raise the efficiency of production processes, and reduce emissions. Several manufacturing industries have already implemented solutions to good effect by using digitization. Mining companies, for example, are using historical data about equipment health to predict potential failures, while aeronautics and automotive companies are using robotics and end-to-end digital twins to improve their design and production processes. Not surprisingly, first adopters of digitization in many industries have gained an edge over their competition. The cement and aggregate industry can better manage the enormous energy consumption, rising cost challenges, inefficient uses of raw material, logistic problems, emissions, and overall process complexity that are inherent in their operations by doing the same. This paper presents the results of a literature review and analysis and conveys the challenges for adaptation and implementation of digitization and artificial intelligence (AI) in the cement and aggregate production industry.

Mar 2, 2022

By Yuexin Han, Mu. Yufan, Yanjun Li, Peng Gao, Yongsheng Sun

"The objective of this study was to evaluate the effect of reduction temperature, reduction time and binary basicity on the size of metallic iron particles in coal-based reduction products of an oolitic iron ore. The particle size distribution behavior (i.e., cumulative passing percentage and mean size of metallic iron particles) during reduction was investigated in detail. Results showed that the particle size distribution of metallic iron particles was strongly influenced by reduction temperature, reduction time and binary basicity. The cumulative passing percentage and mean size significantly increased with reduction temperature and time in the entire range of the experiments. All curves of cumulative passing percentage versus particle size under different conditions demonstrated a similar trend (continuous increase). The size distribution parameters and mean size slightly increased with increasing binary basicity and significantly decreased when the binary basicity exceeded 1.0. The size of metallic iron particles could be controlled by adjusting the reduction conditions during coal-based reduction.IntroductionThe increasing demand for iron ore coupled with diminishing high-grade iron ore reserves has resulted in the urgent need for innovative technologies in order to use refractory iron ores. Oolitic iron ore is a typical refractory iron ore with tremendous abundance globally. Based on published literature, oolitic iron ore reserves are approximately 140 million tons in Europe, 10 billion tons in China and 66 million tons in Pakistan (Kazmi and Abbas, 2001; Wu et al., 2011; Yu and Qi, 2011; Sun et al., 2013a). Therefore, the efficient exploration and use of oolitic iron ore resources can play a significant role in easing the mineral resource crisis in the iron and steel industry. However, oolitic iron ore cannot be effectively upgraded by traditional beneficiation methods due to its mineralogical characteristics (e.g., low grade of iron, poor liberation of iron minerals and high phosphorus content) (Li et al., 2011b; Sun et al., 2013b).Researchers recently proposed coal-based reduction followed by magnetic separation to recover iron from refractory iron ores (especially oolitic iron ore) and a certain degree of breakthrough was achieved in both theory and practice. In this technology, iron minerals in the ore are directly reduced by coal to metallic iron, which grows into particles of different sizes. After comminution and liberation, metallic iron is concentrated by magnetic separation (Srivastava and Kawatra, 2009; Sun et al., 2013a; Li et al., 2011b; Sun et al., 2013b; Li et al., 2011c; Gao et al., 2013). Sun et al. and Gao et al. used this technology to examine the recovery of iron from oolitic and Bayan Obo iron ores, respectively (Sun et al., 2013a; Li et al., 2011b; Li et al., 2011c). Metallic iron powder with more than 90% iron content was obtained as the final product, which could be used directly in steel production."

Jan 1, 2015

By Mark C. Holton

The mining industry has recently been. - experiencing a difficult period. Escalating costs, lower grades and deeper level mining, are a few of .the reasons' why interactive graphics or CADD (computer aided design and draughting) systems are increasingly being used. CADD systems which support powerful and flexible mining applications have great potential for making all forms of mining more efficient and effective. There are many application programs which address almost every aspect of mining. Most of these programs originated to satisfy a particular need. Graphics and other features were added until they, reached a point where they were commercially viable as a mining package. Because of their evolution these packages, lack many CADD-type features. Today there are powerful personal computers (PC's) and engineering workstations running the best CADD systems available. These systems, support hundreds of applications in almost every discipline. Mining was until recently not well supported by interactive graphics vendors because of the highly variable nature of mining and the lack of common standards. Users of CADD systems have experienced the benefits of CADD and come to expect similar features from graphic mining packages. Several developers of mining packagers have either attempted to include some CADD features or make their packages compatible with one or other CADD system. Mining can benefit greatly From a combination of interactive graphics (or CADD) and the right mining application software.

Jan 1, 1989

The structure of a mine ventilation network (M.V.N.) can be represented graphically using either the mine plan (map) itself or a number of other types of diagrams. In the U.S., the two most common approaches are the line and the schematic diagrams (see Figures 1 and 2). The purpose of this paper is to introduce another type of diagram, called the canonical diagram (6). The method of M.V.N. representation which uses canonical diagrams is used extensively in Europe, and especially in Poland, where it was developed. The canonical diagram is a noncalibrated topological image of a ventilation system. It gives a simple representation of the ventilation network, allows for the classification of currents within it and enables rapid computer analysis and computation, as well as the representation of the results. It is especially useful in studying and controlling the air flow, and it may be a life saving tool in conducting rescue operations during and after mine fires.

Jan 1, 1986

By D. G. Chedgy

Careful consideration is given to the type of cleaning equipment and control sys- teas to be used when selecting circuits for wash-ing fine coal (28M x 0 size fraction). However, the desliming, declaying and sizing procedures required to ensure efficient operation normally are not evaluated in sufficient detail resulting in disappointing system performance. This paper details desliming and dewatering circuit design which is extremely effective based on recent test data. The circuit maintains control of the 28M x 0 (declayed) size fraction with minimal misplaced material and maximized circuit efficiency. A discussion of circuit design parameters and control systems, as well as results from the testing program, are included in this text.

Jan 1, 1986

By Chunbao Sun, Qi Liu, Chao Wang

Entrainment is a process by which fine and ultrafine particles are transferred to the flotation froth from the top of the flotation pulp, and eventually discharge to the concentrate product, evenwhen they are not attached to gas bubbles. Therefore, entrainment can be considered as a two-step process, one at the upper layer of the pulp to the flotation froth, and the other from froth to the concentrate. Entrainment is inevitable for both hydrophobic and hydrophilic minerals and is one of the significant factors affecting concentrate grade. This paper provides a comprehensive review of the entrainment mechanisms and entrainment models, as well as a summary of the main factors affecting entrainment and the techniques thatmay be used to lower or eliminate entrainment. Based on the review, we point out that selective aggregation of fine and ultrafine gangue minerals using appropriate process aids (polymeric depressants, inorganic salts, etc.) to increase their particle sizes appears to be a convenient and economical method. Directions of further research along this line are discussed.

Aug 31, 2020

By James E. Kolesar

An essential prerequisite to expanding the application of longwall mining techniques in the United States is the development of a better understanding of the mechanics of rock mass deformation near the mined seam, in the inter- burden and at the surface. The results of studies of this type will provide a basis for the development of empirical and/or numerical modeling techniques to predict the rock mass response to mining both near and far from the mined seam. This will lead to improved gate and panel design, resulting in maximum recovery, increased productivity, as well as provide a mechanism for assessing likely surface effects induced by long- wall mining. Presented here is the instrument plan to be used at Kitt Mine No. 1 in the study of rock mass response to two adjacent longwall panels.

Jan 1, 1982

By Charles L. Kimbell

The year 1988 for the minerals indus¬try was one of favorable worldwide economic conditions for continued, rationally constrained growth. There was continued improvement in relations between market economy nations and the Soviet Union and China. The "shooting war" between Iran and Iraq ended. Soviet troops withdrew from Afghanistan. And conditions were generally favorable for economic growth in developed market economy countries. These favorable conditions were darkened only somewhat by the continuing foreign debt crises discernible in some major mineral producing developing market economy countries. However, there were situations developing that became major headlines in the late spring - situations that may have pronounced effects in 1989. The most significant event is the muddled situation in China. There is a good chance of worsening international relations and consequent restraint of development projects that could prove beneficial to China and her international partners. Of only slightly lesser evident significance was the death of Ruhollah Khomeini in Iran. This could lead to a variety of paths for the new Iranian leaders. Continued outbreaks of ethnic unrest in the Soviet Union clearly presented problems to the Gorbachev regime. This unrest has raised questions of how far the doctrines of "glasnost" and "peristroika" would be extended, including extensions into the minerals field. Another area of unrest is Panama with its tainted election and the Western Hemisphere's obvious dissatisfaction with the Noreiga regime. While not a direct threat to any major mineral industry enterprise, the political situation certainly presents a potential threat to the Panama Canal. That threat would have considerable impact on world

Jan 1, 1989

By George R. Mitchell

It is a common observation that objects having, different; temperatures exchange energy by radiative transfer. The quantity of radiant energy emitted by an object is a definite function of its temperature. Therefore, a measurement of emitted radiation, by means of a calibrated radiometric instrument, provides a temperature measurement without contacting the emitting object. The physical laws describing radiant energy transfer and their application to remote temperature measurement form the substance of this paper. The energy radiated by bodies having temperatures up to 4000°C is largely in the infrared spectral region. The infrared spectral region is that part of the electro-magnetic spectrum having wavelengths longer than visible light and extending to the microwave region. The wave-lengths range from 0.7 micron (1 micron = 10-4 cm) to 1000 microns. In general, infrared radiometry deals, with the methods of measuring energy flux in the 1 to 15 micron region of the infrared spectrum.

Jan 1, 1960

By Harry Perry

U. S. consumption of sulfur and sulfur products is expected to increase at a rate of 8 percent per year between now and 1980, largely as a result of their use in fertilizer markets. World consumption is also increasing rapidly, but at a-lower rate, about 6-percent per year. In 1965, sulfur recovered in the United States from purification of natural gas; nearly doubled from the 1956-1960 average; production from pyrites declined; and production of elemental sulfur increased 15 percent. Concern about air pollution resulting from sulfur oxides produced from the combustion of fossil fuel has lead to intensive research on methods of removal before combustion, during combustion (in-process methods), and from the resulting flue gases. If all the sulfur in fossill fuels were recovered, more sulfur products would be produced than were consumed in the United States in 1965. Removal of sulfur from coal before combustion could result in a product sufficiently-high in sulfur to be a suitable raw material for sulfuric acid manufacture. In-process methods produce solid sulfates, some of which may have commercial value. Flue gas removal' methods for sulfur oxidest generally result in the production of a byproduct either of sulfuric acid or sulfur. The projected sale of these materials significantly lowers the anticipated cost of sulfur dioxides pollution abatement. Alternate methods for sulfur dioxide reduction are discussed. The various proposed processes are described and costs are given for the various methods for which estimates have been made.

Jan 1, 1967

By Kenneth N. Han

The effect of anions such as sulfate, chloride and nitrate on the solubility of rare earth element (REE)-bearing phosphates and fluoro-carbonates was examined using relevant thermodynamic data. The study found that these anions have significant influences on the overall dissolution of REEs from various sources in the aqueous media.