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By S. Lee, F. Campero

"Past heap leach design has evaluated hydrodynamic parameters based on a uniform particle size of heap material, but has ignored the equal importance of the instability of fine migration within heap stack in the beginning stages of the irrigation process. The proposed probabilistic model evaluates internal fine erosion and segregation potential of well-graded crushed ores by considering the entire particle size distribution shape and site compaction degree. Using this model, unsaturated flow model parameters were successfully evaluated based on synthesized soil-water characteristic curve (SWCC). Additionally, one-dimensional unsaturated transient flow modeling with Hydrus 1D® showed that the different recovery efficiencies of heap material under unsaturated flow patterns depending on the particle size distribution and compaction degree of heap material. Agglomeration preprocess employed by most heap leach sites can reduce the potential of fine erosion within heap material significantly, but internal stability of crushed ores and hydrodynamic-based analysis of heap material’s pore structure is equally important in the prescreening stage in order to improve efficiency of the heap leach and avoid a costly agglomeration process. INTRODUCTION Accurate estimation of heap leach recovery is a difficult task due to the variety of design parameters that need to be considered - such as geochemistry, hydro-dynamics, and geotechnical design aspects, most notably particle size distribution through the process of agglomeration. After agglomeration techniques were introduced to heap leach design, the influence of particle size distribution and compaction degree in enhanced heap leach recovery has been neglected. The main purpose of agglomeration is to prevent fine segregation and internal erosion during and after heap stacking for well graded crushed ores, which will eventually diminish heap reach recovery. Recent studies show that agglomerated heap materials that had been consolidated at 10 meters below heap surface can release the fines after contact time with lixiviant to the compacted heap material and produce poor drainage performance (Milczarek et al, 2013). It must be noted that engineers and practitioners should investigate feasibility of agglomeration benefit prior to heap leach design because the agglomeration process can incur up to 20 or 30% of project costs. Internal stability of stacked heap material is mainly governed by the particle size distribution of crushed ores. Depending on this stability, segregation and internal erosion of fines can be mitigated by the application of moderate compaction effort during heap construction. Investigation of segregation and internal erosion potential therefore takes precedence for well graded crushed ore since reaction time and contact area with lixivant are greater in finer ores."

Jan 1, 2016

By M. P. Neira

In-situ leaching of copper from chalcocite relies on ferric iron concentration in the lixiviant being reduced to ferrous. To re-establish the ferric concentration in solution, ferrous must be re-oxidized. This reaction is slow under normal chemical conditions but it is catalyzed by Thiobacillus ferrooxidans bacteria. BHP Copper's Miami In-situ unit developed a bio-reactor as a method of oxidizing ferrous to ferric. The effects on oxidation of temperature, CO2? oxygen, and air injection flowrate were defined. This paper summarizes the results of ferrous bio-oxidation using plastic column packing and oxide ores as bio-reactors and the leaching results of the bio-reacted lixiviant on chalcocite ores.

Jan 1, 1997

By P. Sangurmath, C. Gundewar, M. Riyazulla, V. Vasudev, N. Shadaksharswami

Dharwar craton in the southern Indian shield, comprises the Neoarchaean foreland in the west and a relatively younger accretionary complex composed of granitoids and intervening gold-bearing volcano-sedimentary belts. The Hutti schist belt hosting a major gold producing mine is situated in the northern part of the eastern Dharwar craton. It is a horse-shoe shaped structure comprising predominantly of pillowed metabasalt of tholeiitic composition with minor amounts of clastic sediments and felsic volcanic rocks. The belt is intruded on all sides by circular to tabular bodies of granites and granodiorite. Important gold deposits are located at Hutti, Hira-Buddini and Uti villages. Felsic volcanics in the Hutti belt occur as tabular bodies of quartz porphyry and breccia. Two of the gold-bearing reefs in the Hutti mine, Viz., Middle and Strike reefs are intimately associated with tabular sub-vertical sheets of mylonitic quartz-feldspar porphyry intruding pillowed metrabasalt. In Uti mine area, the felsic volcanics occurs as a tabular body. At Hira-Buddini, the felsic volcanic occur as a irregularly shaped sheet in pillowed metabasalt. Mineralogical and geochemical studies suggest that the felsic volcanic rock in Hutti mine area is a rhyolite and at Uti and Hira-Buddhini it is of dacite composition. Scheelite occurs as veins, veinlets, stringers and blebs along fracture planes of felsic volcanics in the Hutti mine area, whereas at Uti and Hira-Buddini it is insignificant. On the basis of spatial association of metabasalt and felsic volcanics and on geochemical grounds, we interpret that the felsic volcanics might have originated by the partial melting of basalt. REE patterns of the granite, granodiorite and metabasalt of Hutti are similar to each other indicating that they could be co-magmatic. However, REE in the Hutti felsic rocks is significantly higher than in Uti and particularly Hira-Buddini mine areas. The two felsic volcanic samples drawn away from the mineralized zone from all the three mine areas were analyzed for tungsten. In Hutti one sample assayed 0.15% and another 0.062%. At Uti, in one sample it assayed 0.056% and another less than 1 ppm, whereas at Hira-Buddini, it is less than 1 ppm in both the samples. The spatially associated basalt analyzed 23 to 235 ppm tungsten, whereas granites and granodiorites have very low (<1 ppm) tungsten. Therefore, the source of tungsten in the felsic volcanics of Hutti area could be traced to metabasalt. The absence of significant amount of tungsten in the felsic volcanic of Hira-Buddini could be attributed to the lack of REE enrichment compared to REE in Hutti and Uti felsic volcanics.

Jan 1, 2007

By T. E. Burns

The process engineer is frequently requested to select equipment to separate brine from solids, In many cases, this is a more difficult task than the selection of most other pieces of process equipment because quite often the operation of the various types of debrining equipment cannot be predicted by calculations, One must rely to a great extent upon experience or empirical test work to predict performance - that is to say one must use a practical rather than a theoretical approach. This is not to say that the solutions to liquid-solids separating problems are wholly an art but rather it is to emphasize that the approach demands a fair knowledge of commercially available liquid-solids separating equipment, some background on the advantages and limitations of each type and in many cases might necessitate a fair amount of test work, or at least, a study of performance of equipment on similar applications.

Jan 1, 1966

By S. Asokan, D. Rathod, Ch. V. G. K. Murty

Tata Steel, a steel arm of Tata Group, is Asia&apos;s first and India&apos;s largest integrated private sector steel company. Tata Steel’s turnover in fiscal 2004-05 was nearly US$ 3.25 billion. As part of its vision to grow in related industries, Tata Steel is poised to enter the Titania businesses in the Indian state of Tamil Nadu. The Titania project will involve mining, separation of ilmenite & other co-minerals, beneficiation of ilmenite to synthetic Rutile and further maximum value addition to Titanium metal. This paper outlines the journey from the concept to current findings of the Bankable Feasibility Study in developing Sattankulam Heavy Mineral Sands Deposits in the State of Tamil Nadu, India by Tata Steel.

Jan 1, 2005

By Andrew E. Nevin

The government of India convened a precedent-setting meeting in New Delhi on Nov. 12, 2001.The meeting brought together regulators and the mining industry in an attempt to fix the industry’s mine development problems in that country. More than 150people attended the all-day session. Ram Vilas Paswan, Minister of Coal and Mines, chaired the meeting. Ravi Shankar Prasad, Minister of State for Coal and Mines, was also present. The secretary of the Department of Mines and the Joint Secretaries and Additional Secretary also participated. The Department of Mines’ mandate is for economic growth: to get new mine development going and to make investment in mining attractive for both domestic and foreign-owned companies.

Jan 1, 2002

By Jill Dill Pasteris

Several mineralogical prospecting techniques are used in diamond exploration. Most are concerned with identifying indicator minerals such as garnet and ilmenite, which are derived from mantle xenoliths hosted by kimberlites. The first goal of such prospecting is to locate kimberlite intrusions; the second goal is to identify the diamond-bearing kimberlites. Explorationists have worked much less on the indigenous kimberlite phases. The kimberlitic opaque oxides, ilmenite and particularly spinels, promise to be useful in discriminating between intrusion episodes in identified kimberlites, and perhaps in the evaluation and prediction of diamond grades. Several petrologists have showed that spinel compositions and zoning patterns are specific to certain intrusive facies in South African and Canadian kimberlites. Careful evaluation may indicate a correlation between spinel parameters and diamond content.

Jan 1, 1983

By K. V. Raj, A. Miller

"Workers at mineral processing facilities are often exposed to high levels of dust generated when ores are processed. Crushing, grinding, screening, and other processes generate large quantities of dust, which can exceed the threshold VALUES (prescribed by the Mine Safety and Health Administration (MSHA). Many ores contain quartz (silica), which has been known to cause serious health problems in workers over time. Given the structure of mineral processing plants, the airflow regime is not coherent inside the building, which may lead to multiple recirculation zones. These recirculation zones can trap dust, and concentrations of dust can then rise over time. Therefore, there is a need to understand the airflow phenomenon that occur inside of mineral processing facilities and how these occurrences interact with the dust generation processes to identify zones of potentially high dust concentration. Computational fluid dynamics (CFD) modeling can give a better understanding of the airflow and help recommend designs and methods to mitigate the high dust concentrations in a mineral processing plant. This paper presents the CFD modeling of airflow inside of a mill building to demonstrate airflow patterns that will affect the generation and subsequent dispersion of dust due to crushing, grinding, and other activities. This study was conducted by researchers from the National Institute for Occupational Safety and Health (NIOSH). INTRODUCTION In a mineral processing facility, minerals go through various mechanical processes in order to reduce their size for separation of economic minerals from gangue minerals to produce a final marketable product. This research, conducted by the National Institute for Occupational Safety and Health (NIOSH), focuses on ore mills in metal and nonmetal mining (MNM) operations, but the applicability of the approach will be valid for any large structure where workers are exposed to airborne contaminants. The processes of crushing, grinding, cleaning, drying, and product sizing in these facilities generate a large amount of dust, creating hazardous conditions for the workers in these facilities. This is highlighted by the fact that MSHA sampling data for the years 1997–2012 indicate that 12.3% and 15.9% of the gathered samples were over 100 µg/m3 for silica for metal and nonmetal mills, respectively [1]. Mineral processing operations typically use some type of engineering control to address their most significant dust sources. Engineering controls include such approaches as bag-house-type dust collectors, scrubbers, and electrostatic precipitation [2]."

Jan 1, 2018

By M. Irish, M. Jahraus

Accurate prediction of gold (or other metal) production from a heap leach operation is essential to the economic vitality of any such operation. However, this is also one of the most challenging issues facing managers of these facilities. Three approaches to modeling gold production from the Valley Leach Facility (VLF) at Anglogold’s Cripple Creek & Victor Gold Mining Company are presented. Evolution of these modeling methods has been necessary as ore heights and volumes have increased. In addition, the complex geometry of the VLF presents additional complications to production modeling, Comparison of actual and predicted gold production are presented

Jan 1, 2001

By Tim Arnold

"Justified is a show on FX that takes place in Kentucky coal country. The two main characters, a cop named Raylan and a criminal named Boyd, are adversarial to the very end, yet they manage to maintain a seemingly inexplicable bond of friendship through it all. The final episode ends (spoiler alert) with Boyd asking Raylan why that is. He responds, “If I allow myself to be sentimental, there is one thing I wander back to” Boyd responds, “We dug coal together.” Fade to black.What creates these types of bonds between friends and co-workers in mining? I don’t know about you, but many of my best friends I met in mining. Certainly the people I respect the most in this world are a part of our industry. Good, honest, honorable men and women. And I am not just talking about the leaders of our industry. I am talking about great miners who taught me how to do the right thing and also be productive.I have had the pleasure to work for some great people and the misfortune of working for some of the loudest screamers. What I consider the worst butt-chewing in my life may surprise you. I once worked for a man I respected, because he showed me respect. He went on a business trip and left some instructions. For some reason, I was able to justify to myself that they applied to everybody but me, and I disobeyed them. When he returned he called me into his office and said to me: “Tim, you pissed me off when you did that.” He said it quietly and with no anger. I had lost his respect. This devastated me more than any screaming shift boss ever could have. I learned a lot about values from that conversation.Most of us will spend more time at work than we will with our families over a lifetime. It is natural that tight bonds be created at work. What I believe makes mining special is that these bonds are so strong. They are strengthened by the incredibly hard work our miners do. They work at all hours, on holidays and in all sorts of extreme weather conditions. The physical demands of the job are sometimes exhausting. Our bonds are further reinforced because the work is dangerous. Not only does management watch out for the wellbeing of their people, but each and every one of us looks out for one another. The bonds are made tight because our people are so passionate about what they do, no matter the department or profession. Finally, they are strong because of the thousands in the industry that keep doing the right thing, every day. We make great friends in this industry because of the strength of character of our people. That is why Boyd and Raylan respected one another so much."

Sep 1, 2016

By B. Pina

The conversion of maf coal to pyridine solubles and gas was investigated in a microautoclave batch reactor for two Kentucky washed coal samples (Ky. #9 and Ky. #11). Solvent hydrogen donor strength was controlled by the tetralin content of a mixed 1-methyl naphthalene-tetralin solvent. Primary liquefaction conversions greater than 90% in 10 minutes of reaction time at 427°C were achieved in liquefaction solvents with moderate hydrogen-donor strength (circa 40% tetralin). A modified irreversible first order rate expression, containing a parameter (a) to account for the intrinsic reactives of the maf coal, described the experimental kinetic data rather well. The integrated form of this rate expression is -k1e x = a (a- ß)e (eq. 1) Parameter ß in equation (I) is the pyridine solubility of the starting maf feed coal, x is the primary liquefaction fractional number of conversion, k1 is the specific reaction velocity constant and ? is reaction time. Primary liquefaction rate was found to be quite temperature sensitive and independent of coal when a liquefaction solvent containing 40% or more tetralin was employed. Primary liquefaction rate appears to depend on liquefaction solvent hydrogen donor strength for solvents containing = 40 wt.% tetralin. The intrinsic reactives in the maf feed coal or a appear to depend mainly on the inertinite group maceral content of the coal for the two coals studied in liquefaction solvents containing 3 40wt.% tetralin. In contrast, a appears to decrease in liquefaction solvents of low donor strength., i.e; solvents with less than 40wt.% tetralin.

Jan 1, 1984

By William Gleason

"Technology of all forms has experienced exponential growth in recent years, and there is no sign of it slowing down. This growth has presented amazing opportunity and significant challenges in nearly every aspect of daily life. Some of these changes are seen and experienced every day as we turn to our smart phones, tablets and smart watches to help with us with everything from directions to the store to managing our health. And other technological growth takes place far away from the public view but can have as much of an impact on our daily life as does shopping at Amazon or connecting with friends on social media.At the “THRIVE 2018, Innovations Advancing Mining” conference presented by SME on Sept. 27 at the Sheraton Pittsburgh Hotel at Station Square in Pittsburgh, PA, the focus was on innovation and how it affects the global mining industry.More than 100 people were on hand for the inaugural event, and they were treated to a unique program that focused on the cutting-edge innovations that will carry the mining industry into the future while increasing safety and productivity along the way.2018 SME President Barbara Arnold was the driving force behind the conference and put together the technical program with a focus on innovation through the entire mining life cycle and into the future. Talks ranged from more efficient and safer ways to extract minerals to some of the most advanced end uses of minerals and metals, including the use of 3D printing to create precision parts for machines and humans from advanced metal alloys.“We need to adapt new technologies to our industry and develop additional technologies as we provide materials and metals for infrastructure and energy development in the United States, around the globe, and to the Moon and beyond,” Arnold told Mining Engineering. “Our inaugural THRIVE conference sets the stage for these innovations to be applied and to continue to be developed. Our mining industry can only continue to thrive with these advances.”"

Jan 11, 2018

By W. Langer

Of the 50 or so most often utilized industrial minerals, more than two thirds are, or have been, produced in the western states of Arizona, Colorado, Idaho, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wyoming. Some commodities, such as natural aggregate, currently are produced in all 13 states; others such as beryllium and iodine are produced in only Utah and Oklahoma, respectively. Together, the 13 western states make a significant contribution to the US industrial minerals industry.

Jan 1, 2007

By Brendan Demich, Joseph McGuire, Emily J. Haas

Near misses recorded and reported by workers can provide awarenessto the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, it is unclear what the value of these reports are, if any, and how they influence subsequent actions or controls to reduce on-the-job risks. Researchers at the National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. Of those, 167 were valid near misses that occurred at work. Researchers coded the reports using a qualitative 5 × 5 risk matrix. Of the 167 near misses, 19% were deemed low risk, 25% moderate risk, 30% high risk, and 26% critical risk. Several patterns in the near-miss incidents were documented, including classification of incidents and common corrective actions referenced (i.e., elimination/substitution, engineering control or redesign, work process/procedures, and personal protective equipment). The analysis provides insight into ways that risk communication and management programs can be improved to reengage workers and their situational awareness on the job.

By Youngtak Ko, Wonnyon Kim

Korean contract Mn-nodule field in the NE equatorial Pacific is composed of seven sectors showing average water depths of 4,513 - 5,025 m. Of the various factors controlling the property of Mn-nodules, water depth has a potential linkage to chemical composition, shape and abundance of nodules. To clarify such a possibility, we review more than 20 years of research data in one of the northern sectors (hereafter KR1) where there is a marked contrast in water depth. High-resolution seabed mapping clearly separates a northern part from a deeper southern part, cutting across the middle of the KR1. In terms of nodule occurrence, manganese nodules in the deeper north are comparatively larger (2-4 cm) with rough surface (t-type) and discoidal shape (D-type), while those in the south are generally small (<2 cm) with smooth surface (s-type) and irregular shape (Itype). In addition, the nodules in the north have higher metal contents including Cu, Mn and Ni. Such connections of water depths to nodule occurrence and metal contents are commonly observed in the Korea licensed Pacific nodule fields. However, the relation between nodule abundance, size and water depth may be a different story. In KR1, nodule abundance and size are probably controlled by morphological features especially in the north. Seamounts in the north continuously provide rock fragments as new nuclei for the nodules. As a result, the nodules can not grow larger than 2 cm and show the shapes of newly formed nodules (i.e., smooth surface and irregular shapes). Such an interpretation is supported by anomalously high backscattered intensities in the side-scan sonar image map of the north, which possibly reflects a younger generation of magmatic activity.

Sep 1, 2014

By Jan M. Mutmansky

Since 1973 when the first edition of the SME Mining Engineering Handbook was published, many significant changes have occurred in the US mining industry. The industry went through a fairly prosperous period immediately after 1973, but then many economic pressures came to bear on mining companies, particularly in the metal and coal branches of the industry. These pressures changed both the mining methods used and the general economics of the mining methods. As a result, the industry today is different in many ways titan it was in 1973. A general summary of some of the more important changes that have come about will be provided here as well as some assessment of the effects of these changes on the choices of mining methods. In the metal mining industry, the most significant trends were increased surface mining, the use of larger and more efficient equipment, and increased technology and automation. The primary impetus for these changes was unprecedented competition from foreign producers. In many cases, this competition came about because of the nationalization of foreign mines and the tendency for these mines to become a source of foreign exchange. Under these circumstances, the mines could be operated even though they were not profitable. As a result, domestic

Jan 1, 2008

By Liliana Rybarska-Rusinek, Aleksandr M. Linkov, Ewa Rejwer-Kosińska

Joined modeling of stressed state and induced seismicity is a means to join geomechanics with seismic observations. When applied to quantifying rockburst hazard, it provides, on one hand, estimations in terms of mechanics, such as stress concentration, and, on the other hand, in statistical terms of the risk analysis developed in mining seismology. The modeling became possible due to progress in computers and numerical methods. However, despite tremendous increase of computational abilities, the joined modeling is still quite time expensive. To make it available for wide use and real time simulations, there is need to reduce the time cost of its key stages: calculation of stresses, caused by mining, and simulation of seismic events, induced by these stresses. The present work aims to decrease the time cost. The stages are time costly because of the same reason, which is a very large number N (up to millions) of elements, representing rock structure, openings and flaws. This leads to immense computational complexity (roughly of order N2) of conventional accounting for pairwise interactions between the elements. The complexity may be notably reduced, when employing the fact that interactions decrease with growing distance between elements. Specifically, the fast multipole methods (FMM) avoid the complexity N2, by employing translations of far-fields from whole collections of sources. This reduces the complexity to the order 22, where p is the number of terms involved in a single translation, is the number of translations, and is the dimension of the quantity translated. Still, for conventional FMM, the complexity remains too high to routinely perform joined modeling of stresses and seismicity.

Apr 26, 2022

By Gary Brierley, Lok Home

"The majority of tunnels for civil engineering applications are now being constructed using some form of mechanical excavation. Beginning in the 1960s with rock tunnel boring machines (TBM), the tunneling industry has introduced both earth pressure balance (EPB) and slurry pressure balance (SPB) soil machines; mixed soil and rock machines and a variety of different mechanical devices for the construction of small diameter tunnels. Over time, these machines have become more powerful and more adaptable to a wider variety of ground conditions; so much so that tunnels are now being constructed in ground conditions and in the vicinity of third-party impacts that would have been considered beyond the state of the art just 10 years ago. Figure 1 is an example of a mixed ground crossover TBM used successfully at Mexico City’s Túnel Emisor Poniente II.All of the above is highly advantageous for the tunneling industry, but it has also placed a much higher level of risk on the performance characteristics of the tunneling machines, on the contractors operating those TBMs and on the manufacturers of those machines. Most of the risks for a tunneling project are associated with creating the space inside of which the finished facility will be constructed. In order to create that space, the tunnel contractor must make many decisions about the best way to excavate the ground, the best way to control the ground at the face of excavation and the preferred method for supporting the ground around the tunnel in a manner that is safe for the workers and stable with respect to all of the overlying and adjacent existing structures. If it is proposed to use some form of TBM in order to build the tunnel, then the TBM becomes central to all three of these activities and becomes an integral part of managing the risks associated with these activities."

Jan 9, 2018

By M. Javier

In business mining, dilution is the result of the operating parameters that occur too often and cause serious consequences to mine performance, questioning TO WHOM BENEFITS DILUTION. Mining persists in changing perception of real meaning of dilution. The lack of interrelation between mineral processes and nature compromises the understanding of dilution; this absence of interrelation occurs due to the misinterpretation of nature, otherwise, Geomimic could be helpful to filling the gap of misinformation. NATURE provides LIMITED metals in low content deposits; it is a challenge to obtain them. Nature never considers dilution. Furthermore, though dilution is a human concept, dilution is accepted and promoted. Reality of dilution is in its errors accumulation that translates into technology level or status applied in nature. It is doubtful that dilution can continue surviving if it is ?meaningless?. It will discourse: Is dilution illegal? If the change occurs in the prediction of mining will prevail a different destiny, it is important to touch the cores of the business; otherwise, it would represent repetition of the same ?negative? effects, as usual. Mining defines many losses during the disturbance of nature, from NPV elaboration to the metal recovery to commerce, demanding BETTER DESIGN. This paper introduces and applies MANAGEMENT BY LOSS, as first steps, to limit risks and uncertainties in mining. As result, the management of dilution will be obtainable under mining practices which promotes its character of SUSTAINABILITY.

Feb 23, 2014

By Marline J. Veesaert

Urban quarries offer one of the greatest opportunities for profit in non-metallic mining with limited financial risk IF properly evaluated, planned and developed to meet market needs. Location, with respect to market, is the prime consideration. Geologic considerations and quality of rock are nearly as important. Cost factors and return on investment (ROI) are the principal financial considerations. Risk of capital is determined by weighing all factors that should be considered and how well judgements are based on information acquired. It is a simple, true axiom of business that an investment must be founded on amount of capital required with its expected return plus profit, expertise required to operate and time involved. Urban quarries generally offer excellent stone product market opportunities. Costs of land with mineral containment and processing operations are much greater than in rural areas. Environmental problems have become increasingly severe. Competition from other quarries in the market area is usually directly proportional to the profit attractiveness. Risk of capital (initial, developmental and operational) can be evaluated and reduced only by thorough analysis of the entire situation. Time and money expended on planning and preliminary investigations probably represent the most productive investment of available company resources.

Jan 1, 1977