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By T. A. P. Sankar, S. Gundiah, Pradip, R. A. Kulkarni

Two modified polyacrylamide flocculants, namely polyacrylamide with glycolic acid functionality (PAMG), and a copolymer of acrylamide with N-acryloyl-[T]- aminobutyric acid (HPVP), were synthesized, characterised and evaluated for selective separation in apatite/quartz and apatite/dolomite/calcite systems, respectively. PAMG flocculant was found selective in the separation of tricalcium phosphate (TCP) from its mixtures with quartz at acidic to neutral pH range. The selectivity deteriorated at alkaline pH. In contrast, polyacrylic acid (PAA) flocculant was found most effective only in the alkaline pH range. HPVP flocculant (even though flocculating all three minerals namely apatite, dolomite and calcite) was observed to be quite selective for the separation of calcite from apatite-dolomite minerals in single mineral tests in the presence of sodium hexametaphosphate dispersant at neutral pH. There was, however, no selectivity observed during tests on synthetic mixtures. This loss in selectivity is attributed to the phenomenon of hetero-flocculation, as reported earlier, for separation in an apatite-dolomite system with polyethylene oxide.

Jan 1, 1993

By J. A. Herbst, A. E. Oblad, Y. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50% of the operating cost. Improvements in plant operations have resulted in up to a 15% reduction in energy usage (kw-hr/t). These improvements have been made through the optimization of grinding efficiency and the use of expert model-based control systems. Optimization involves the determination of the levels of the critical-operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory test work and through computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding-circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1997

By Tim O’Neil

Many mining companies try to fight their way up from small operator and exploration company to major producer. Not many companies make it. Cambior Inc., formed in 1986, is one company well on its way to making it as a major operating company. In 1993, Cambior surpassed 15.5 t (500,000 oz) of gold production and began operations at its world class Omai gold mine in Guyana. At the same time, the company has embarked on a program of geographic and minerals diversification. Cambior, a Canadian company, now has interests in eight mines, three development projects and more than 100 exploration properties in North and South America. The company’s goal is to derive 70% of its income from gold and 30% from base metals and other minerals. Cambior’s moderate diversification into base metals gives protection against negative gold price fluctuations. It also balances the typically short term gold mines and the longer term base metal mines.

Jan 1, 1994

By S. Ersayin, I. Iwasaki

Laboratory- and pilot-scale tests were carried out to study the effects of a magnetically enhanced hydroseparator on a magnetic taconite sample. The test parameters included feed flow rate, percent solids and magnetic field strength. Laboratory tests showed that magnetic iron losses could be effectively prevented by applying a magnetic field strength of 0.003 T (30 gauss) to a hydroseparator. A relatively uniform magnetic field within a pilot-scale hydroseparator was obtained by installing a magnetic grid within the device. The test parameters for the pilot-scale study also included the effects of magnetizing/demagnetizing the feed and magnetizing current. Magnetic iron losses were substantially reduced, even when the hydroseparator was operated at very high upward velocities. Results also show that increasing the field strength decreased the losses, but magnetic enhancement was successful even at the lowest field strengths, and the results show that magnetic iron losses were lower when the feed was magnetized. Key words: Hydroseparator, Magnetic field, Magnetic grid, Taconite processing, Magnetizing, Demagnetizing.

Jan 1, 2003

By K. N. Han, Q. Xu

The adsorption behavior of gold in ammoniacal solutions on activated carbon was studied. The gold adsorption capacity of the activated carbon and the recovery efficiency were examined. The parameters affecting the adsorption of gold on the activated carbon included temperature, agitation speed, the concentration of cation and anion and the concentration of ammonia. It was found that the maximum gold adsorption was about 10 kg/t of carbon. The recovery of gold by the adsorption, from ammoniacal solutions was found to be dependent upon the initial gold concentration. Under experimental conditions, a gold recovery of 98% was obtained after 120 hrs of adsorption. It was also found that the initial adsorption rate was relatively fast, when compared to the entire adsorption period. The apparent activation energy for the adsorption was determined to be 15.8 kJ/mol. It was believed that the kinetics of gold adsorption on the activated carbon was controlled by pore diffusion.

Jan 1, 1997

By M. Elzeky, A. Attia

The effects of bacterial adaptation and partial replacement of leaching solution on the rate and extent of bioleaching reactions of a complex sulfidic gold ore were investigated. The ore was first concentrated by bulk sulfide flotation and the sulfide concentrate was treated by bioleaching using T. Ferrooxidans bacteria. The residues from bioleaching were treated by cyanidation to extract the gold and silver. Bacterial adaptation before bioleaching significantly increased the rate and extent of bioleaching reactions. Similarly, the daily partial replacement of leaching liquor enhanced to a great extent the leaching rate and in some cases up to ten fold increase was observed. Both bacterial adaptation and solution replacement increased the gold recovery by about 2-fold and that of silver by about 1.3-fold. In this work more than 95% of the gold and more than 98% of the silver could be recovered from the sulfidic gold ore, when bioleaching was used ahead of cyanidation compared with 18.3% and 52.3% by direct cyanidation.

Jan 1, 1989

By J. C. Mullen

Today, the coal mining industry is more knowledgeable on the potential negative economic consequences associated with improper management of hazardous substances and various types of solid waste. The practices evaluated during environ-mental audits are discussed and example situations are shared from previous audits of coal mines and analogous situations. The importance of assessing and understanding purchasing, warehousing, safety, maintenance, electrical, operations, and environmental management practices and procedures is highlighted as a key to a successful and practical program. A waste minimization approach is presented including strategies for screening product purchases, product substitutions, and testing and record keeping.

Jan 1, 1992

By R. E. Vivas, J. A. Villa

"INTRODUCTION Located in the state of Colima, Peña Colorada is one of the largest iron ore operations in Mexico. The project is owned in equal parts by ArcelorMittal and Ternium. Though boasting a production capacity of 4.5 million tons of concentrate per year, Peña Colorada is faced with declining ore grades. In order to respond to this situation, Peña Colorada had to expand production even further. This expansion created various challenges that were overcome by the adoption and application of new technology. Examples of these technological innovations are discussed in detail in this paper and include improvements in geo-modeling, mine planning and mine operations. The successful implementation of these technologies paid for itself many times over, and has led to significant improvements in production and performance, while lowering the operating costs and reducing the variance between planning and execution. PROJECT OVERVIEW Peña Colorada is a mining company which produces about 30% of the iron ore in Mexico. This project generates about 1,200 direct jobs and 3,000 indirect jobs, making a significant contribution to the local economy. Similarly, Peña Colorada invests in its local communities through numerous educational programs, scholarships, university agreements, social development, environmental agreements, etc. Peña Colorada’s operations consist of an open pit mine located in Minatitlán and a pellet plant located in the port city of Manzanillo, as shown in the location map below:TECHNOLOGICAL INNOVATIONS Most mining projects around the world typically follow the logic of “mining the next best ore”. Consequently, head grades tend to decline over the life of the mine. In the case of Peña Colorada, a decline in head grade combined with a decline in iron ore prices forced the operation to adapt to a new business environment and adopt new technologies to face these challenges. However, the first step along this process was to increase the confidence and reliability of the resource model. This task involved additional drillhole campaigns coupled with more detailed modeling techniques. Once the block model was completed, new optimization studies and production schedules were evaluated with new optimization tools that unlocked significant project value in many aspects of the mine plan. Similarly, new geotechnical studies were prepared, which provided new guidelines for pit slope design, and new technology was implemented to monitor ground movement and slope stability. The picture below shows two sectional block model views in MineSight 3D, along with the pit designs and geologic solids"

Jan 1, 2017

By Karl C. Dean

To assist in the reduction of environmental degradation resulting from milling operations, the Bureau of Mines has developed, and successfully demonstrated, chemical, vegetative, and combined chemical-vegetative procedures for stabilizing milling wastes under varying environmental conditions. Costs of achieving reclamation using these stabilization procedures are compared with those of other physical and vegetative approaches. The Bureau's chemical-vegetative procedure for establishing vegetation directly on fine-sized wastes compares favorably with other stabilization processes that have been used.

Jan 1, 1972

By C. Van Landingham, A. Bailey, R. A. Schoof

A residential metals abatement program has been underway in Butte for more than 20 years. More than 1,350 yard and attic cleanups were completed by the end of 2018; most triggered by lead. While the focus is on remediation of residential soil and house dust, the program also includes a blood lead monitoring program with identification and abatement of additional sources of exposure for children with elevated blood lead levels (BLLs). As specified in the remediation program, studies are being conducted every 5 years to assess BLL data collected from Butte children. The first two studies have evaluated over 6,000 BLLs from 2003 through 2017 and evaluated trends over this time period, by Butte neighborhood, and as compared to areas outside of Butte. These studies showed that rates of elevated BLLs (i.e., those above 5 µg/dL) in Butte children have declined dramatically since 2002 but have been declining much more slowly since 2011. Improved rates of confirmation testing are needed to verify the rates of elevated BLLs. While the RMAP likely has contributed to these declines in BLLs the magnitude of impact cannot be quantified.

Mar 2, 2022

By Warwick Hoffmann, Robin Batterham, David Conochie

CRA has been actively involved in developing a bacterial oxidation process for the treatment of low grade, refractory gold resources. Success in this application is dependant on the design of large, energy efficient reactors. It was identified at an early stage, that the conventional, bottom sparged bioreactor is inherently inefficient because air must be compressed to a pressure above that at the bottom of the tank. This inefficiency increases as the size of the reactor increases. CRA has developed a novel approach to the aeration problem. In this, venturi aeration is used to aspirate air into a liquor stream. The stream is then reintroduced at the top of a draft tube bioreactor. The advantages found with this technique include · low energy requirements and high oxygen utilisations. From results at the 30 m3 scale, we predict an energy usage of -500 kWh/t sulphur oxidised at a scale of 1000 m3.

Jan 1, 1993

By Harry Holle, Gary Johnson

A plant trial was conducted at the Paddy's Flat plant of Dominion Mining Limited with the aim of comparing the ef evenness of oxygen and hydrogen peroxide as leaching oxidants. The Paddy's Flat plant is designed such that the leach train can be divided into two parallel streams, allowing the same or lurry to be eated in two identical trains. By effectively ehminatmg the influence of the ore variations on the results subtle differences in the performance of the two reagents hav been identified. . . The results of the plant trial indicate that the two reagents act m different ways, and that each may be more suitable than the other _for _the treatment of certain types of ore. In some cases a co bmation of the two reagents may be the most cost effective option. . or t e same chemical conditions in the leach pulp, including dissolved oxygen levels , the reagents achieve different gold leaching rates, and in some cases different ultimate leach extraction.

Jan 1, 1992

By Mark A. White

Surface mining of multiple seams by mountaintop removal and contour mining is complex in Appalachia. Arch of West Virginia, a division of Apogee Coal, has made its operations state-of-the-art to cope with this challenge. Arch of West Virginia moved into the heart of coal mining in Appalachia when Arch Mineral acquired coal reserves and coal operations in the southern West Virginia counties of Logan and Wyoming. These reserves were initially developed at the turn of the century as underground operations. Today, though, they are mined using mountaintop removal and contour mining. The steep slopes in the mountains of Appalachia generated a method of mining referred to as contour mining. During the late 1960s and early 1970s, contour mining was introduced at these operations using front-end loaders with bucket capacities of more than 7 m3 (10 cu yd) that could load 45-t (50-ton) end-dump trucks.

Jan 1, 1995

By W. M. Shaver, R. Letourneau, W. R. Dengler

Dynatec Mining Ltd. contracted to sink a 1500-m (4920 ft) concrete-lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft has an inside diameter of 6.3 m (20.5 ft) and is equipped with steel furnishings. Dynatec used the owner-supplied, 4.6-m (15.1 ft) diam, double-drum hoist to sink the shaft. For muck removal, 12.5¬t (13.8-st) buckets were used. The capacity of the concrete-¬placement buckets was 4.6 m3 (162.4 ft3). One of the unique features of the shaft sinking operation was the use of a two-¬boom, electric-hydraulic drill jumbo permanently mounted in the shaft sinking stage. An in-the-hole (ITH) drill was used to drill a 200-mm (8-in.) cut hole for the 4.8-m (16 ft), full face rounds. This paper describes the performance obtained with the electric-hydraulic drilling equipment and the high-capacity muck removal and concreting equipment.

Jan 1, 1994

By Karl Ingmarsson

Larger mines spend millions of dollars annually on rock drilling tools, but often purchase based on historic consumption. The results vary from excess inventory to acute tools shortages. These lead to emergency sourcing, sometimes mixing products that don’t perform optimally. Boart Longyear analyzed the usage pattern of 96 thousand drill bits at thirteen different underground mining contracts, showing very high variability. The monthly standard deviation on a product level was 42%, with the highest for development and low volume bits. A new rule of thumb is suggested to carry only one month of safety stock for high volume bits, but increase to three months for low volume bits. This balance will reduce the risk of outages with less inventory. The accuracy can be improved by considering the specific conditions at each mine and reclassifying individual bits for a different safety stock level. Root cause analysis and collaborative forecasting between mines and suppliers can lead to further optimization of availability and inventory levels.

Feb 1, 2024

By C. Pace, D. Darlington, A. Montera, C. Lingren

"A phosphate beneficiation plant in Utah is using isotope-based Prompt Gamma Neutron Activation Analysis (PGNAA) technology to analyze the entire slurry streams of the incoming feed and final product in order to adjust the flotation circuits in near real time and optimize the plant output. The plant has gained greatly improved visibility/control and has reduced product variability for improved profitability and product quality. This paper takes a look at the economics as well as application details and the difference this technology provides in a phosphate application. SIMPLOT PHOSPHATES INTRODUCTION Simplot’s Vernal, Utah Phosphate Mine and Mill are located in the northeast corner of the state in the Uinta Mountains along US Highway 191, eleven miles north of the town of Vernal. The phosphoric acid and fertilizer plant fed by the Vernal mine is located 94 miles Northeast of Simplot Phosphates in Rock Springs, WY.At the Vernal plant, loader and shovel mining to 85 Ton capacity trucks is done at an annual rate of 3.8 Million tons of ore. Run of mine ore is crushed in a mineral sizer to minus 14 inch diameter at the rate 11,500 tons a day and transported to the SAG Mill’s 130,000 ton surge stockpile by overland belt. ORE RESERVES The ore is a Phosphoria Formation of sedimentary rock type dating to the Permian Age. The ore body rests over a 25 mile area on Weber Sandstone from the Pennsylvania and Permian geologic period. Layers of Phosphate Rock can vary in thickness from 0.3 up to 2.1 feet, alternating with layers of Mudstone. The eastern edge of the ore’s body Panel “G” runs 16 feet deep with a feed grade of 21.5% P205 with lower MgO diluents of less than 2.79%."

Jan 1, 2016

By A. Delgado-Jiménez, O. J. Restrepo-Baena, G. Aristazabal

"Mining industry as a source of raw material is essential to society however, it lacks of good reputation due to the type of management historically applied to many of its social and environmental impacts. It is argued that this situation has hampered the obtaining of social license to operate of a lot of mining projects around the world. The last considerations are very common in Latin American countries. As a result, the mining sector has understood that the viability of the business long term is associated with more profit for the shareholders but also with activities that improve the livelihoods of local communities, enhance the capabilities of local governments and preserve the ecosystems around the projects. Nevertheless, recent studios have shown that most of the current advances to incorporate sustainability concepts in mining have been mainly focused on control and the prevention of environmental and social impacts of extractive activities. Thus, contributing to the development of territories around mining projects constitutes a fundamental aspect of the business competitiveness through reducing cost and risks of stopping projects, innovating new ways of relationship with stakeholders, improving the level of reputation of the industry as well as its position in the market. However, this contribution requires formal strategies and models that enable companies understand the different resources in the territories where their mining activities are developed and those resource transformations, in order to establish the best way to articulate the project with the territory, pursuing an effective contribution to its development, truly sustainable over time even after the mine closure. CONTEXT Currently in the world but especially in developing countries such as Latin Americans, different stakeholders are increasingly vigilant of how mining companies carry out their activities in terms of socio-economic and environmental management of territories, not only for its impact on the livelihoods of the communities that inhabit them, but also because many demanders of raw materials -both countries and companies- have set sustainability standards as a prerequisite to establishing business relationships with mining companies, such as the recently declared Sustainable Development Goals by 2030 (UN, 2015). Accordingly, decide underinvest or not to invest in sustainability issues carries risks for mining companies. However, invest much in the wrong way may involve the same risks. Managers are concerned to ensure profits, and therefore they decide carefully how to invest in the areas of production, R & D or marketing. Likewise, they should think strategically about investing in initiatives related to sustainability. This if they really want that those investments in fact help to improve the competitiveness of the company. The mining industry benefits from natural capital that extracts, so it should implement strategies that lead to remunerate such benefit to the territories (Almaguer, 2007). One option is through the transformation of natural capital in other types of non-existent capital or poorly developed in their areas of influence. In this way, the value generated by the extraction of underground resources is shared and additionally contributing to improving the quality of life of the communities. Historically, mining industry has been into several problems to achieve this, which represents one of the aspects that has most influenced the current reputation of mining industry in some regions of Latin America. Many communities, local governments and civil society organizations continue to associate this activity with the destruction of the social fabric and ecosystems in the territories, and their opposition against companies working in the areas has led to affect the operational continuity of many projects (Hamann, 2003; Prno and Scott, 2012; Slack, 2012)."

Jan 1, 2017

By P. A. S. Manning

Eastern Jamaica consists predominantly of non-carbonate rocks reaching elevations of over 2200 m. The area is drained by a well established river network which supplies close to 30% of the sand and gravel used by the building and construction sector. Present high extraction rates and slow rates of replenishment will result in early exhaustion of this source of aggregate. A number of volcanic and carbonate rocks are being examined as a possible source of high quality aggregate which meet the requirements for all types of construction. Preliminary evaluations show a dacitic deposit to be the most suitable source for aggregate use.

Jan 1, 1998

By W. Robert Power

Dimension stone includes a wide variety of natural materials that are put to an equally wide variety of uses. It is possible to classify dimension stone according to the end use to which the stone is put or according to the lithology of the stone. Both schemes are used by the United States Bureau of Mines in the annual Minerals Yearbook. The 1969 Yearbook lists 15 specific uses and has additional miscellaneous catagories. The same Yearbook lists five specific rock types or lithologies, and also includes a miscellaneous category. In a short presentation it would hardly be possible to list and define all these categories, much less discuss the evaluation of deposits with regard to all possible combinations. Besides, I am only slightly familiar with some of the uses and their requirements. I have therefore chosen to limit my remarks to some special problems in evaluating dimension stone that is to be cut and finished to specific sizes, tolerances, and finishes for use in buildings and some monuments. This use class is called cut stone in the Minerals Yearbook. In terms of dollar value it is the largest single use category. In 1969 the dollar value of cut stone was $29,122,000 which is more than twice the value of the next largest category. For those of you who are interested in other use applications of dimension stone I suggest that you start with recent articles by Bowles (1960), Currier (1960), and Barton (1968).

Jan 1, 1972

By O. J. R. Baena, I. C. Sánchez, J. L. G. Guzmán

Frontino, a municipality in western Antioquia, Colombia, has more than 200 years of mining tradition. Currently, mining activities are carried out for lode gold using subway tunnels, where the grinding of the material is done in "cocos", whose energy depends on internal combustion engines and ACPM, environmentally polluting and inefficient methods. In accordance with the Sustainable Development Goals as an initiative developed by the UN, different mining methodologies that are aligned with these are constantly being analyzed. This study proposes to eliminate the use of hydrocarbons in artisanal mining, mainly promoting Sustainable Development Goals 7, 9, 11, 12, and 13. This will be achieved through an energy transition to renewable energy sources that take advantage of the topography and water resources of the area, providing advantages to the communities that live there, such as lighting, electricity for cooking, ventilation for mines, etc

Mar 2, 2022