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By NILAMADHABA SAHU, Gajanan U. Kapure, Pankaj Kumar, Sunil Kumar Tripathy

Chromite ore processing tailings and low-grade manganese ores are typically considered waste due to their limited or negligible utility, leading to environmental and storage concerns. Researchers globally have explored various methods to utilize or upgrade these wastes, particularly because dumping chromite ore has been linked to severe health issues through Cr(VI) leaching. Individually, these ores lack economic value, and there has not been research on simultaneously reducing both low-grade ores. In this study, the focus lies on smelting these ores together, aiming to create a precursor alloy for 200 series stainless steel scrap. Initial research indicates the potential for scrap formation, validated through laboratory experiments with varying coke rate, basicity and holding time. The investigation discovered that smelting this combination could yield a metal product consisting of 59 percent Fe, 24.93 percent Cr, 7.56 percent Mn, 0.62 percent Ni and 0.93 percent Si. The optimum basicity was found to be 0.6 with 80 percent recovery. Notably, this process eliminates intermediate steps in 200 series stainless steel production, potentially reducing overall carbon dioxide emissions. This proposed method represents a cleaner, sustainable approach to repurpose these two waste ores, projecting a net profit of US$330/t.

May 1, 2024

By G. G. Huggins

A demonstration project has been completed to reduce the operator sound level of an underground service vehicle, a personnel dispatch wagon, to go dB(A) or less. The program objective was to implement quieting recommendations made on an earlier study for the USBM n diesel-powered mine equipment. The manufacturer and mine to which the vehicle was going actively participated in the program to ensure a product that was not only quiet, but useful. The key element of the quieting package is an engine part a1 enclosure, which, with several complementary noise control components, reduced the operator sound level 14 dB, from 101 dB(A) to 87 dB(A). The vehicle underwent a 4-month trial period, with no degradation in the quieting package. Mine personnel reported no maintenance difficulties, and were enthusiastic about the dispatch.

Jan 1, 1975

By Thomas J. Crocker, Douglas B. Uthus

Tunnel Boring Machines (TBM) have gained worldwide acceptance in the construction field and are being employed in ever increasing numbers to drive underground transit lines, drainage systems, etc. However, TBM utilization in the mining industry, and more specifically coal mining, has been very limited. This paper reviews past and present applications of TBMs to coal mining and examines the needs of the industry in an attempt to offer some insight as to what a TBM system must provide if the excavation potential demonstrated in civil works projects is to be realized in coal operations. EUROPEAN EXPERIENCE Germany The Germans recognized long ago the potential of mechanized drivage for coal mine entry development. Early in the 1960's experimental runs were made with a full-face Wohlmyer roadheader at the Westerholt Mine and trials were conducted on a roller bit armed full-face Bade roadheader. But because of problems with penetrating the various carboniferous strata occurring in changing sequence and hardness, these first attempts were soon terminated. After viewing later successes in the construction industry with improved TBMs, new attempts were initiated by the German mining industry in 1971 to mechanize drivage of their development entries. Four TBMs of two different types were placed in operation.

Jan 1, 1976

By Francis G. Stehli

Though sedimentary rocks comprise only about five percent of the volume of the continental crust, they cover about 80% of its surface, serve as important reservoirs for fluids, contain reserves of non-metallic minerals, and have in general been extensively drilled. However, most drilling has been shallow in comparison to the thickness of the crust and such deep drilling as has taken place is very strongly localized in sedimentary basins. This may be seen by reference to Figures 1 and 2 which show the location of wells that drilled deeper than 15,000' [=] 4.6 km. (Figure 1) and those that drilled below 20,000' [=] 6.15 km. (Figure 2). It is apparent that, even in regions of sedimentary cover, direct exploration below six kilometers has been very restricted. In the case of the metamorphic and igneous rocks which make up 95% of the volume of the crust, direct exploration has been much less extensive in terms of both area and depth. The present state of our knowledge of the crust below a' thin surface layer stands in marked contrast to our growing present need for raw materials and the needs of future generations. It also stands in contrast to our need for enhanced, scientific knowledge of the deeper crust, its configuration, its present state, its hydrothermal systems,-its evolution, and its materials. Lessons learned in exploring the third dimension of the sea floor, the vigorous prosecution of seismic profiling, the development of testable models for hydrothermal systems and mineral deposits, the need for better understanding of heat flow, state of stress, earthquake mechanisms, and a host of other phenomena all suggest that it is time to launch a national program for scientific exploration of the crust which uses drilling to test important hypotheses developed on the basis of indirect evidence.

Jan 1, 1985

By George H. K. Schenck

Diminishing returns in management's fight to lower manufacturing expenses have added luster to savings that can be achieved in delivered costs through creative management of the distribution function. This is especially true for companies engaged in the production of bulk commodities, for which transport costs may represent 25 to 50% or more of total delivered price, A. E. Cascino, vice president of International Minerals and Chemical Corporation, recently gave an example of why top management in his firm is concerned with distribution: "The price of a ton of phosphate rock, f.o.b. mine, is about $7. The cost of warehousing, freight, and handling frequently totals an additional $11 . . . . If one of our competitors . . . discovers a way in which he can cut his distribution costs by $3, we're dead! Even if we wanted to offset our competitor's more efficient means of shipping with reduced f.o.b. price for our product-we don't have that much profit margin . . . ." In a special report on the revolution now occurring in transportation of goods, Business Week stated in its September 24 issue: "Moving and storing goods on their way from mine and mill through various sub-assemblies to their final markets costs anywhere from $50 billion to $75 billion a year- $100 billion if paperwork costs are included.

Jan 1, 1967

By Grant Wallace, Rod James, Larry Twidwell, Ed Rosenberg, Courtney Young, Sean Dudley, Hsing-Hsin Huang, William Gleason, Jerome Downey

The use of applied chemistry in the production and optimization of leach solutions from Rare Earth Element (REE) ores and concentrates is being investigated. Ore and concentrate samples were characterized using scanning electron microscopy/mineral liberation analysis (SEM/MLA), X-ray diffraction (XRD), and Atomic emission inductively-coupled plasma spectroscopy (ICPAES). Multiple leach tests were performed to analyze the effects of temperature, residence time, and reagent concentration on the leaching of REEs. Analysis of leach solutions was carried out using ICP-AES. Modeling and statistical analysis of extraction behavior was carried out using DesignExpert 9. Modeling data for cerium extraction indicates that extraction is greatly influenced by temperature and reagent concentration, while leaching time plays a much less important role. Experimental design techniques are being utilized to optimize REE recovery. Results, conclusions, and directions for future studies will also be discussed.

Jan 1, 2015

By Luis W. Pommier

The developed processes, the subject of this paper, extract the hydrocarbons, halogenated organic compounds and metal contaminants from hazardous soils, rendering them non-hazardous and ready to be placed back on the ground. The processes first segregate a non-contaminated fraction from the contaminated soil. This initial task is performed using available minerals processing technology: sizing, gravity separation, magnetic separation, froth flotation, etc. The remaining contaminated fraction, is submitted to two leaching operations for the removal of organic and metal contaminants, whenever both are present or to a single leaching operation if only one type of contaminant is present. The decontaminated soil fraction is mixed with the non-contaminated fraction and is placed back on the ground. The leaching liquors, used at neutral pH, are non- hazardous. After decontamination the liquids are processed to extract the contaminants, now valuable materials, for commercialization. Organic contaminants are removed by distillation of the solvents. The metal contaminants are precipitated in their oxide form. In both cases the regenerated solvents are recycled. The decontamination processes are economically competitive with transportation and disposal of the soils to permitted facilities for hazardous materials, and most importantly the developed processes remove the liabilities from the Responsible Parties. The law establishes that these liabilities do not disappear with either fixation nor with transportation and disposal since the environmental liabilities are of the ? cradle to grave? type.

Jan 1, 1994

By C Torrisi, J Andreatidis, M Duffy

BHPÆs Cannington process plant was commissioned in October 1997. The Cannington ore contains high grades of silver, lead and zinc but also contains high levels of fluorine which must be removed to produce a marketable concentrate. As a consequence the plant is more complex than the typical base metal concentrator. Some of the features of the Cannington operation include a single stage autogenous mill, multiple stages of flotation cleaning, two leach circuits, pressure filtration and a paste fill plant. The start-up and achievement of design performance for new lead/zinc operations has traditionally taken much longer than for gold or copper operation and is littered with many tales of woe with feasibility targets often not achieved (Agarwal, Brown and Katrak, 1984; Bulatovic and Wyslouzil, 1999; Leung, Andreatidis, Woodall and Alford, 1996; Sherman, 1999; Ward, 1998).

Jan 1, 2000

By Nick Karl, David Wilburn

"The mission of the U.S. Geological Survey (USGS) National Minerals Information Center (NMIC) is to collect, analyze and disseminate information on the domestic and international supply of and demand for minerals and mineral materials essential to the U.S. economy and national security. Understanding mineral exploration activities and trends assists government policy makers, minerals industry decision makers and research entities in identifying where future sources of mineral supply are likely to be discovered, the amount and type of these resources and factors that may affect exploration and development.This review summarizes significant exploration trends related to active sites and budgets, mineral commodities and regional factors for the years 2001-2015. Data were compiled by specialists in the USGS-NMIC, and reported annually in the USGS-NMIC Minerals Yearbook series and in the May issue of Mining Engineering magazine. External data for these analyses were derived from industry sources, published literature, and SNL Metals & Mining, an offering of S&P Global Market Intelligence (New York, NY).The USGS-NMIC compiled exploration site data for more than 80 mineral commodities, focusing on base metals, diamond and precious metals. More than $138 billion constant U.S. dollars were budgeted by the minerals industry from 2001 through 2015 to explore more than 16,000 mineral deposits globally (SNL Metals & Mining, 2016a). Annual analyses identified where mineral exploration took place by principal commodity target, ranked the magnitude of activity in each region, identified the factors that most affected changes in exploration activity and highlighted developments that led to changes in global supply or increased diversity of supply to the United States. Geographic classifications noted in this report were Africa, Australia, Canada, China, Latin America, Pacific, Russia, United States and Rest of the World."

Apr 1, 2017

By B Wong, R G. Coleman

In flotation, the selection of the size, number and type of cell for a particular duty depends on two important factors. Firstly, the required flotation residence time and secondly, the physical constraints of how much concentrate can be recovered for a given froth surface area and concentrate lip length. The residence time is influenced by ore type and characteristics such as liberation, kinetics and reagent dosage. The amount of concentrate that can be recovered for a given froth surface area and lip length depends on ore type and other characteristics such as particle size, specific gravity and mineral grade. Residence time is determined through a combination of laboratory-scale test work and design scale-up factors. However the critical froth transport parameters such as froth carry rate and froth lip loading cannot be determined in a laboratory. This is because the froth is scraped during a laboratory flotation test and thus does not exhibit natural behaviour, and it is not possible to scale-up froth transport distance or air rate. These values are generally compared via calculation to rule-of-thumb maximum values to establish if these values will be exceeded by the flotation cell selection.This paper first reviews these critical froth transport parameters and then discusses actual parameter values across diverse operating sites, with varying cell duties, cell sizes and types, orebodies and particle sizes. These values are compared against the industry rule-of-thumb to test the applicability of the rule-of-thumb to actual performance. Options are also presented for adjusting these parameters in operating flotation cells.CITATION:Coleman, R G and Wong, B, 2018. Flotation launder design and the measurement of critical froth transport parameters, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 353–362 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

What is your assessment of the status of the mining industry as we see some evidence of an economic recovery? I am optimistic about the short and midterm prospects for the industry and, hence, for the professionals in the industry that constitute the majority of the SME membership. All who will read this interview recognize that the quality of life we enjoy today is largely a result of our achievements in the mining and minerals processing sectors. I believe that the sustainability of that quality of life and the aspirations of other sectors of the global community to attain that same lifestyle will significantly depend on the continued successes of these industries. Looking at some of the traditional economic indicators, we see predictions of continued increases in gold prices during the next 12 months as a new round of quantitative easing keeps real interest rates low and drives excess capital flows from countries with trade surpluses - who have traditionally parked their money in U.S. government bonds - into other investable assets, such as gold. On the fuel side of the industry, we have during the last decade seen a steady rise in the cost of coal, and some of the recent spot prices have seen dramatic increases. Some suggest that coal prices may rise sooner than anyone expects, as global reserves are revised downward. This is based on the hypothesis that some of the main coal-producing countries are overestimating supplies and that coal prices could start rising far sooner than anyone thinks - with obvious serious implications for energy policy. Those forecasters note that, for the past couple of decades, global supply has been dropping at a faster rate than consumption.

Jan 1, 2011

By T. S. Bannos

Section 1417 of the Safe Drinking Water Act Amendments enacted by the O.S. Congress prohibits the use of lead containing solders for potable water systems in new construction or when making repairs. The legislature defines "lead-free" solder as containing less than 0.2% lead. In the development of a new solder it was recognized in addition to the lead free requirement, the alloy should perform as well as the popular 50/50 tin lead solder, both in application and properties. Another objective was to have only nontoxic elements. This led to the development of a 4.0% copper, 0.5% silver and 95.5% tin solder. Review of the merits of other alloy systems and the development of the physical properties along with test data are presented for the lead free tin. rich alloy.

Jan 1, 1990

By Jeffrey C. Schuh, Logan Bloemer, Daniel P. Dietzler

Over the past 30 years, the authors have encountered numerous projects where recognizing the geology, soil properties and groundwater conditions, and considering alternative construction techniques have promoted efficient and cost-saving construction. The construction documents for these projects, produced by various engineering firms, provided basic information on geotechnical conditions. The authors became involved in each project either because there was a problem during design or construction or, as a contractor, won the project because they saw a value engineering opportunity to take advantage of the geologic setting of the project to design and build alternatives to what the designer depicted. Understanding the geologic setting is critical before planning and designing begins. Being able to work with the geology and the materials on site is preferred before specifying more costly and complex solutions, which often require the importing of materials and adherence to unnecessary and/or inappropriate specifications. Failing to understand the geology or not knowing all the techniques available for construction can lead designers to develop solutions that could be inappropriate. This paper presents several examples of value engineering and project performance enhancements developed through knowledge of basic soil mechanics and implementing innovative solutions. History and Background Most people attend DFI meetings, present their experiences, listen to others, and read articles and papers with the hope they can learn from others. Geotechnical engineers and contractors often interface with others in the execution of projects who have, at best, a rudimentary knowledge of geology and soil mechanics. Of course, there is a need for architects, bankers, and regulators, etc., but they typically do not have much interest in the nuances of geotechnical engineering, which relies on both art and science. Thus, significant time is spent educating counterparts in the need for comprehensive subsurface investigation programs and the intricacies of construction in the “dirt,” as they typically refer to soil and rock.

Jan 1, 2019

By Bernardo J. Jiménez Vega, Edy L. T. Montalvan PhD

The experience gained during more than 900 Crosshole Sonic Logging (CSL) tests on drilled shafts shows the importance of establishing proper project acceptance and repair protocols. Drilled shaft evaluation is a multidisciplinary task that should not be left solely to the outcome of the CSL test. This test allows to characterize and delimit areas of different qualities of concrete, and it is important that all the interested parties understand the difference between flaws and defects. The information presented here is intended to give a guideline to contractors, inspectors, engineers, owners and clients on how to deal with acceptance and remediation of defective drilled shafts, detected using CSL tests. A database of flaws is presented depending on their location, intensity and remediation method. Procedures that allow the flaws to be analyzed are presented in order to dismiss or classify them as defects. In many cases, the CSL test may indicate an anomaly, but by coring the concrete and analyzing the structural demands and conditions, the flaw can be classified as non-severe. When flaws are classified as defects, their repair will depend on the area where they are located in the drilled shaft pile. In this document two procedures are described for repairing defects depending on their location. For defects in the drilled shaft head area, the procedure takes into account the interaction between the new and old concrete. For repairing the middle zone of the drilled shaft by grouting, the major concerns are the difficulty of accessing through the drilled shaft at deep depths and the communication between boreholes. For defects at the drilled shaft tip, two proposed remediation methods are presented. Finally, tomography tests are presented to compare the effectiveness of remediation by grouting.

Oct 1, 2022

By Graeme J. Jameson

"When mineral particles are floated in a mechanical flotation cell, it is found that the rate constant, after reaching a maximum value, starts to decline as particle size increases. It had been thought that the reduction in rate constant had been due to the increased prevalence of composite particles in natural ores, for larger particles. However, Jameson (2012) showed that the rate constant for composites is certainly a function of the surface liberation, but the reduction in flotation rate is independent of particle size. Thus all particles are equally affected by reduced surface liberation, independently of their size. He further argued that the classical peak observed in the rate constant with increasing particle size, is a function of machine hydrodynamics. Thus in mechanical cells, the peak may be due to the high energy dissipation rate and its effects on the detachment of particles from bubbles (Goel and Jameson, 2012). Consequently, in a different flotation environment, it may be possible to float large composite particles that cannot be floated in mechanical cells. This paper describes the flotation of large composite particles in a fluidized bed flotation cell. The particles to be floated are fed to a column in which there is a continuous upflow of liquid. A conventional froth layer of controlled depth is formed at the top of the vessel. A fluidized bed of particles is established which provides a gentle environment for the contacting of large particles with bubbles. An example is given where a porphyry copper ore was prepared at a top size of 710 µm, and floated with conventional collector (PAX) and frother (MIBC). The concentrate was separated into size fractions and examined by photography. Composites were observed at all size fractions, but above 400 µm, all particles were composites. The implications for future flotation circuits will be described."

Jan 1, 2014

By William Petruk

Many gold operations lose gold during processing because some ore characteristics which affect recoveries have not been determined, and consequently the plant could not be designed to account for them. The ore characteristics can be determined with mineralogical techniques by analyzing the plant feed, final tailings and mill products. The plant feed and/or final tailings are commonly analyzed first as a separate project. Mill products are analyzed only if the process employs a minerals separation circuit to produce a concentrate (e.g. secondary flotation circuit to concentrate gold-bearing arsenopyrite), and if assays and materials balances indicate a recovery problem in the minerals separation circuit. Many ores have been evaluated at CANMET on a confidential cost-recovery basis by custom-designing a work plan which was dependent upon the problem and on the characteristics of the ore. The reasons for gold losses have been identified in most cases, and suggestions for modifying flowsheets have been proposed. The methods used in performing the analyses are described in this paper, and non-confidential results from in-house projects are provided as examples of the benefits of such analyses. The analytical methodology involves a combination of the following procedures: -producing heavy mineral concentrates and identifying the gold minerals in the concentrates; -determining quantities of invisible gold in gold-bearing sulphides, sulpharsenides, etc. by SIMS; -determining quantities and liberation characteristics of all gold minerals and gold-bearing minerals in the sample; -finding and identifying gold minerals in silicates; -extensive grinding and cyanidation to determine the ultimate amount of cyanidable gold; -determining impact of clay minerals and graphite; -performing a mineral balance for the gold in each sample; -performing a materials balance to determine the distribution of the gold minerals, gold-bearing minerals, and other minerals throughout the flowsheet, and; -interpreting the results.

Jan 1, 1995

By B K. Hebblewhite, G Sharrock

The strength and deformation properties of a rock mass are important parameters influencing the design of civil and mining excavations or structures. The mechanical behaviour of jointed rock masses are controlled by the characteristics of discontinuities and the strength of intact rock bridges between discontinuities. To date, analytical, empirical and experimental methods have not captured the key mechanisms controlling the mechanical properties of actual rock masses with non-persistent joints. The emergence of the synthetic rock mass (SRM) in 2007 provides a promising approach for this purpose. In this paper a rock mass with non-persistent joints is analysed with the SRM model based on PFC3D. The influence of joint geometrical parameters on the uniaxial compressive strength (UCS), rock mass deformation modulus (Em) and failure mode is studied. Joint parameters include joint orientation, persistency, spacing and step angle. Prismatic numerical samples with dimensions 300 mm × 150 mm × 50 mm were generated and a sensitivity analysis of each joint parameter on UCS and Em was undertaken. The results show that of the parameters tested, joint orientation has the greatest influence on UCS. Minimum UCS occurs when the angle between the major principal stress and joint surface is approximately 60°. The joint step angle was found to have a significant effect on failure mode and a joint step angle of 90° is the most favourable joint orientation for step-path failure. The importance of joint step angle is highlighted in the discovery of a failure mode bifurcation point at joint step angles of 60° and 90° for joint orientations of 75° and 90°, respectively. For these parameters the failure mode transitions from block rotation to a new failure mode where the coalescence of cracks results in the formation of new small regularised blocks.

Sep 26, 2011

By H. S. Geismer

INTRODUCTION. THERE are three general methods available for obtaining commercial brown iron-ore : hand-screening; washing; and washing and concentrating. Hand-screening has produced a large tonnage of ore in the past, but is rapidly falling into disuse, except as a preliminary step, largely because modern furnace-practice requires all foreign material to be separated from ores before they are delivered to the furnace, and hand-screened ores can rarely be made to fulfill that requirement. Another argument against hand-screening is, that the waste-pile often contains as much ore as the screen recovers. The operation known as hand-screening consists of throwing the ore-bearing material against a stationary inclined screen of 0.5- to 0.75-in. mesh, similar in construction to the screens employed in sand-pits. The recently-prospected brown-ore deposits of Cuba seem to offer possibilities for hand-screening not possessed by the average American deposit, since these ores are not associated with worthless clays. Washing, and washing and concentrating, may be discussed together, since concentrating is never practical on brown iron-ore, except to treat ores that have already been washed. (Strictly speaking, washing might be classed as concentrating, but it is never so designated by brown-ore men.) The various steps of removing ore-bearing material and converting it into ore suitable for blast-furnace use, may be grouped under five heads: loading for transportation ; transporting ; feeding into the washer; washing; and concentrating. These five subjects will be considered in consecutive order. Each of these successive steps may be accomplished in a number of different ways, the choice depending entirely upon the character of the ore-bearing material to be treated.

Aug 1, 1911

By Erica Lorenzo García, Benjamín Cebrian Romo, Antonio Morato Medina

This paper presents the results of a preliminary study on blast-induced vibrations conducted at a Radioactive Waste Storage Facility, located in Spain. The study was undertaken as a preparatory step prior to the blasting operations required for the construction of a new platform located near critical infrastructure housing very-low, low and intermediate-level radioactive waste. The primary goal was to establish a site-specific vibration attenuation curve to safely determine allowable explosive charges based on their distance to sensitive structures. The study followed the criteria defined in the UNE 22.381-93 standard, which regulates permissible vibration levels for different structural typologies. In this case, the existing facilities were classified as Type III structures, given their heightened sensitivity to vibrations. Two experimental campaigns were conducted. Test 1 consisted of a series of 10 individual blasts with increasing charges, monitored by five strategically placed seismographs to record seismic wave propagation and determine the attenuation parameters via regression analysis. Test 2 simulated a production blast using operational charges of 41.7 kg (91.93 lb), applying different delay sequences (42 ms and 25 ms) between holes to assess wave interference, resonance, and constructive effects. Data analysis showed that the longitudinal component dominated vibration transmission, and the predominant frequencies in the most critical zone ranged between 18 and 20 Hz. Based on these values, a conservative peak particle velocity (PPV) limit of 4.75 mm/s (0.19 in/s) was established for blast design. The recorded vibration levels during the tests remained within regulatory limits, with maximum values of 2.35 mm/s (0.09 in/s) and 2.86 mm/s (0.11 in/s) for the sequenced blasts, and peak acceleration of 0.0464g.

Jan 26, 2026

By Charles M. Cooley

THE continual improvements in. the two extremes of the drilling, unit, the drill and bit, have prompted critical examination of the drill steel, the weak link of this drilling unit. Obviously, little is to be gained from the betterment of the drill and bit if the drill steel which transmits the force needed for drilling from the machine to the bit cannot stand long hard service. The technology of the bit has advanced from the integral type to steel detachables, thence to the tungsten carbide insert. The carbide insert is the most significant advance in the bit, bringing it to the level of a machine tool with its performance records under constant surveillance. Long steel changes have become advantageous because the carbide bit will drill greater footages without replacement than did the steel bit: The development of the tungsten carbide insert opened new fields of endeavor in drilling with percussion drills here- to fore known, but limited by the steel bit. After the introduction of the tungsten carbide bit, drill manufacturers began promotion of long feed shells, lighter drifters and stopers, and easily handled auxiliary equipment. Ultimately this promotion of better equipment was intended to increase the bit-against-rock time of the drill shift. Advantages of the uninterrupted drilling period of a long steel change and faster setup time of lighter drill machines are lost when the shank fails in the machine, rod failure requires continual changing, or the bit breaks off in the hole. The quest for reduced

Jan 1, 1952