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By Julián M. Ortiz, Antoine Caté, Oy Leuangthong, Ilkay S. Cevik

Mineral resource classification relies on the expert assessment of a qualified person (QP) to determine which blocks of a 3D mineral resource model are classified as measured, indicated, or inferred. The decision is often based on a combination of quantitative parameters related to the estimation process and qualitative decisions based on previous experience or preconceptions not captured in the numerical model. As such, the procedure is subject to inconsistency, that is, blocks with similar qualities may end up in different categories, mainly due to the subjective nature of the approach. In this paper, we present a methodology to assist the qualified person in this task by clustering blocks with similar parameters and then classifying them into categories in a consistent and automatic manner that only requires the specification of a few hyper-parameters. The result is a consistent classification into resource categories comparable to the result of a classification done by a qualified person but fully consistent and generated in a short time frame. The procedure begins with repeatedly sub-sampling the block model to determine a distance matrix using an unsupervised random forest approach and then clustering the blocks using the associated distance matrix. Then, all the blocks in the model are classified using a supervised random forest approach, which gives a probability of belonging to each class. The initial class can be determined from the class probabilities. Support vector classification with a radial basis function kernel is utilized to smooth the boundaries between classes and define the final classification. An approach to tune the hyper-parameters of smoothing is provided. The methodology is demonstrated with two examples from two gold deposits. Results are comparable to the classification done by the project qualified person using conventional methods.

Aug 17, 2021

By C. I. Basilio

Pearson's hard and soft acid and base (HSAB) principle may be applied to flotation systems. The HSAB principle states that hard acids prefer to bond with hard bases and soft acids prefer to bond with soft bases. By determining the Drago E and C parameters for the different components of a flotation system, the HSAB principle could be used to explain the selectivity of some collectors such as thionocarbamates against some minerals. Determination of these parameters is done by utilizing Drago's theory and flow micro-calorimetry.

Jan 1, 1991

By B. Anameric

Considerable effort has been directed towards understanding the carbothermic reduction mechanisms of self-reducing, fluxing dried green balls to produce pig iron nuggets. Given the geometry of the situation, some investigators believed that the shrinking core model was applicable. Hence, this study involved investigation of the applicability of the shrinking core model to pig iron nugget production. The experiments involved heat treatment of dried green balls utilizing either a laboratory-scale resistance box furnace or a gas-fired muffle furnace at various furnace temperatures and residence times. The products were analyzed for the following: (i) preferred reaction pattern, (ii) distribution of the metallized areas, (iii) % iron content variation in the pig iron nuggets from surface to center, (iv) carburization pattern and (v) physical and chemical properties of the pig iron nuggets. It was determined that the reduction of iron oxide occurred simultaneously throughout the sample and not beginning at the surface and propagating inward; thus the shrinking-core model was not applicable. Heat transfer and gas diffusion from surface to center were not the rate-limiting steps for reduction and carburization reactions.

Jan 1, 2011

By R. J. Roman

Several research groups have spent considerable time investigating coarse ore leaching. Coarse ore leaching includes both heap and dump leaching. The term "heap leaching" will be used in this paper to mean any type of coarse ore leaching. The results of their work are generally in agreement: the progress of leaching can be described by the shrinking core model and its associated mathematics. The shrinking core model is schematically represented in Figure 1. The particle is contacted by the leach solution on its outside surface and the solution migrates inward by filling the pores on the particle. As the solution filling the pores comes in contact with grains of ore mineral the reagent chemically reacts with the ore mineral to solubilize the contained metal. The solubilized metal diffuses outward to the particle surface and is washed away by the leach solution flowing past the particle. The leaching reagent in the particle interior is replenished by the diffusion of reagent from the surface of the particle to the interior of the particle. If the chemical reaction between the leaching reagent and the ore mineral is relatively fast compared to the diffusion rate of the reagent in the solution in the pores of the particle then leaching proceeds from the outside of the particle inward resulting in a "shrinking core" of unreacted ore surrounded by a "leached shell". The rate controlling step in the reaction can initially be a chemical reaction between the reagent and the ore mineral grain, however, once the reaction has proceeded a short period of time diffusion of the leaching reagent through the leached shell will be the slow step and hence the rate controlling step in the production of metal from an ore particle.

Jan 1, 1992

By Adam Bedell, Paul Derby, Brad Crenshaw

Modified contact grouting was introduced almost 15 years ago as a methodology combining traditional contact grouting and consolidation grouting to address groundwater infiltration into hard rock tunnels that utilize cast-in-place concrete as permanent tunnel support. This process has been used on additional tunnels (since initially presented) as a measure to mitigate both groundwater infiltration and exfiltration. During this time, self-sealing grouts have been developed and have been added to the process to further reduce groundwater infiltration that occurs through cracks and discontinuities within the concrete liner itself. This modification is presented and additional results from the grouting process are discussed.

Jun 13, 2021

By P. James

"INTRODUCTION High sulfate (SO4-2) levels often occur in MIW (mining influenced water) either as the result of oxidation of sulfide minerals exposed by mining activity or by deliberate addition – commonly by sulfuric acid (H2SO4) use in hydrometallurgical leaching activities. Increasing regulation of sulfate discharge is creating new pressure to treat or mitigate sulfate release to prevent its entry into the environment. Current treatments include precipitating as gypsum during lime treatment, filtration separation using membranes such as reverse osmosis and nanofiltration technology, and biological elimination via methods like constructed bioreactors. Blue Planet Strategies (BPS) focuses on improved resource utilization targeting electrolytic treatment and waste conversion into resources and has now demonstrated that its proprietary DEMET™ (Dynamic Electrolytic Metal Effluent Treatment) platform can also remove sulfate from target streams as a byproduct of its usual primary treatment focus points of metal species elimination and/or pH adjustment.[1-6] This powerful new capability can mitigate sulfate contamination and recover the sulfate in a useful and potentially saleable form as a byproduct of improved primary treatments focused on enhancing production or treating waste. This provides a new treatment opportunity and value proposition for lowering overall sulfate consumption/addition or creating new revenue to defray conventional treatment costs. The DEMET Alternative DEMET utilizes a patented electrolytic technology platform employing proprietary dynamic high surface area electrodes in innovative configurations to achieve a variety of novel selective chemistries. DEMET‘s unique elements can yield higher processing rates at practical efficiencies, lower energy consumption, plus improved processing stability and lower maintenance requirements due to enhanced resistance to cell fouling and shorting; while also thwarting cross stream (catholyte vs. anolyte) contamination. Consequently, DEMET can provide a superior, extremely versatile, and cost-effective electrolytic treatment option where a multitude of FEED and PRODUCT stream combinations might be employed in comparison to traditional tankhouse electrolytic cells. Secondary reactions (Figure 1A) which could also occur at the cathode (plating/electrowinning, precipitation/scale formation, etc.) are controlled through process tailoring and operation parameter selection. Additionally, DEMET‘s innovative dynamic system mitigates potential fouling and electrode occlusion or shorting challenges which could occur when process particulars demand some of these secondary side reactions occur."

Jan 1, 2015

By B. E. Davis

A technique was devised by the Bureau of Nines to recover coarse (plus 1.7 m) North Carolina phosphate now discarded as waste. Concentration utilizes the difference in particle sphericity between the relatively flat calcite and the rounded phosphate pebbles. Sizing, treatment in a continuous hydraulic classification system, and grinding upgraded a 17.0-pct-P205 reject to 24.5 pct P205 with a phosphate recovery of 63 pct.

Jan 1, 1985

By John A. Reeves

The unit-train concept of moving raw materials .is considered by many railroad men as the most signifigant contribution to reducing rail freight costs since the introduction of the diesel locomotive. The idea, which involves assigning railroad equipment to only one haul and keeping the equipment rolling results in the maximum utilization of equipment. For example before the unit train was plaged in servige on coal hauled to one of Mid. Continent's customers, about 900 cars and 9 locomotives were needed to move the coal requirements for this plant, compared with. 250 cars and 6 locomotives used by the present scheduling of unit trains. If the economics of unit-train movements are to be achieved, coal companies no longer can use railroad cars as small storage bins on wheels to accumulate their coal in trainload shipments, but, rather, must build large bins which incorporate facilities for the rapid loading of railroad cars in a minimum length of time. In this manner railroad equipment is operated at a high degree of efficiency 'with consequent dollar savings. After negotiations between Mid-Continent, the customers and the Railroad, it was decided a unit train loadout and storage facility at Carbondale was required in order to reduce the delivered price of coal to the customers and thereby contribute to the reduction in the cost of manufacturing steel. Carbondale was selected as the bin site location, because the cost of constructing a railroad to Redstone could not be justified for the tonnages anticipated.

Jan 1, 1969

By Juan J. Monsalve, AMAN SONI, ALEX PFREUNDSCHUH, Nino Ripepi

Ground control failures are one of the main causes of accidents in the underground stone mining industry. Some of the fundamental tools for rockfall hazard identification are related to rock mass characterization and geotechnical discontinuity mapping. Recent technological advances in these methods are related to remote sensing techniques and pointcloud processing software for automated discontinuity mapping. Remote sensing techniques, such as LiDAR and photogrammetry, generate multimillion-point clouds with millimetric precision, capturing the structure of the rock mass. The automated point-cloud processing tools offer alternative algorithm-based methods to characterize and map these discontinuities. However, their applicability is constrained by multiple factors, such as site-specific conditions of the rock mass and the parameters used within the mapping algorithms. This paper evaluates the performance of automated discontinuity extraction software compared with manual virtual discontinuity mapping. Sampling windows from laser-scanned sections in an underground limestone mine are defined and mapped using the Discontinuity Set Extractor (DSE) opensource software. Results from the virtual discontinuity software are compared with manually extracted fractures from I-Site based on reviewing orientation, trace length, spacing, number of extracted discontinuities, and processing time.

By Shiou-Chuan Sun

The froth flotation of coal, differing greatly from that of most minerals1-5, is not improved but rather impaired by temperatures higher than room temperature6-10 This phenomenon has long taunted us for an explanation. Gayle and Associates 8,9 reported the lack of relationship between their contact angle measurements and their flotation of American coals under various temperatures. Bailey and Whelan6 stated that the viscosity of flotation reagents, offering some clue for their flotation of British coals at low temperatures, could not be put forward as an explanation either in whole or in part for the effect of temperatures on coal-flotation. In this paper, a froth hypothesis is proposed to explain the flotation behavior of coals under various pulp temperatures. Test work involved the flotation of coals and the frothing of reagents.

Jan 1, 1966

By Atta Ur Rehman, Kwame Awuah‑Offei

This paper examines the effect of bucket geometry (cutting blade profile, floor profile, and blade thickness), speed, motor power output, and muckpile particle sizes on bucket penetration and draft for rubber tire loaders. The work uses a 1:16 scaled model of a load-haul-dump in full factorial experiments to examine the effect of the variables on penetration and maximum draft. The results show that speed and motor output are positively correlated to penetration and draft; muckpile particle size is positively correlated to penetration and negatively correlated to draft (p < 0.0014). The results show that buckets with a semi-spade cutting nose profile yield the highest penetration (mean 118.30 mm) followed by those with the spade (mean 108.88 mm), which also yield higher penetration than those straight blades (mean 95.19 mm). Bucket floor profile and blade thickness had no significant effect on penetration or draft. Also, we determined that increasing the speed and motor power output, simultaneously, can reduce bucket penetration. Thus, operators should not waste energy for no additional gain or even loss in bucket penetration. Also, the work finds speed and motor power output each combine with muckpile particle sizes to affect bucket penetration. This research furthers our understanding of the effectiveness of different bucket geometries in improving penetration and reducing draft for rubber tire loaders.

Oct 29, 2021

By J. E. Urosek

In October, 1990, a fire started in a large underground coal mine in Western Pennsylvania. During fire-fighting activities, an explosion occurred and all personnel were evacuated. Safe re-entry into the mine was not possible and the mine was sealed. Recovery efforts began in January, 1991 and continued until March, 1991, when permanent underground seals were installed between the fire area and the mine openings. This paper describes an extensive atmospheric monitoring program conducted by the Mine Safety and Health Administration (MSHA), Pittsburgh Safety and Health Technology Center (PS&HTC) including the analysis of mine fire gases, natural ventilation, fan pressure and air quantity distribution.

Jan 1, 1993

By M. SIDDARAJU, Rameshwar Sah, T. Umadevi, K. S. SRIDHARA, M. RAJU, GANESH SHETTY

With the depletion of high-grade iron ore resources, the utilization of existing low-grade iron ores, fines and tailings with effective beneficiation is inevitable to meet the iron and steel industry’s required specifications and demand. JSW Steel Limited is operating a 17-mtpa beneficiation plant at its Vijayanagar site in Bellary in Karnataka, which produces nearly 50 to 54 percent concentrate as sinter-grade fines. The sinter base mix consists of iron ore fines that are smaller than 10 mm, with 41 percent smaller than 0.150 mm; washed ore that is generally smaller than 3 mm and bigger than 0.150 mm, with 3 to 9 percent smaller than 0.150 mm; beneficiation plant concentrate, with 97 percent smaller than 0.150 mm; limestone; dolomite; coke breeze; lime; sinter return fines; direct reduced iron (DRI) fines; and micropellets produced from steel plant waste. Using more washed ore in the sinter base mix affects the sinter quality. Ball formation in the mixing and nodulizing drum is an important step in sinter making and requires sufficient quantity of smaller than 0.150 mm fines. Optimization of fines in the sinter base was carried out by replacing the smaller than 10 mm iron ore fines with washed ore. Size analysis, study of the granulation index (G index) and optimization of moisture with respect to sinter bed permeability were carried out to optimize the proportion of smaller than 0.150 mm fines in the sinter base mix as adhering material. This study explores the optimization of fines in the sinter base mix for ball formation to achieve higher sinter quality and productivity with higher sinter bed permeability.

By Firat Atalay

Estimating the spatial distribution of ore grade is one of the most critical steps to proceed with an investment decision on a deposit. Kriging is the most widely used method to estimate the ore grade, but alternative techniques are being developed. Machine learning algorithms can be used as alternative methods to classical kriging. In this paper, the iron (Fe) grade of a deposit is estimated with the XGBoost algorithm, and the results are compared with kriging estimation results. For the estimations, samples collected from drillholes were used. Due to the different natures of the estimation methods, different steps were taken to perform the estimations. The results show that XGBoost produced higher-range estimates, which is a desired result in ore grade estimation, and the minimum and maximum of the estimates were lower and higher than the kriging estimates, respectively. However, like kriging, the estimation results were smoother than composites, and the variance of the XGBoost estimates was lower than the variance of composites. This means that even though estimation with XGBoost mitigates the smoothing effect, the estimation results suffer from smoothing like kriging.

Dec 1, 2024

By W. R. Sharp

The ability to target, delineate, excavate, and produce local resources is essential to the establishment of man&apos;s long-term presence in space. Many procedures and equipment utilized to mine resources here on Earth may be directly applicable on the lunar surface, while others may need extensive redefinition and development. This paper compares, for a lunar base, the alternative of burrowing into and below the lunar surface with that of surface mining. A conceptual underground mechanical excavator is presented.

Jan 1, 1991

By B. Eiter, M. Barham, T. Bauerle

Fatigue-related risk is a persistent safety concern for the mining industry. However, fatigue and sleepiness are often treated interchangeably, which can lead to confusion and potentially less effective reduction of safety risk. To provide clarity, we present an overview of similarities and differences between work-related fatigue risk and sleepiness including definitions, theories, measurements, and mitigation strategies. As a supplement, a summative visual model which highlights these similarities and differences is presented. Expanding industry knowledge in this area will assist safety professionals in crafting more targeted risk management practices appropriate for work-related fatigue risk, sleepiness, or both.

Feb 1, 2023

By L. Schlink

Impacted waters, often complex, are created in mining which at some point in the mine life cycle will need to be attended. The simplest and most cost effective method of handling impacted water is to reuse it as makeup water for operations. At the end of mine life, operational reuse will not be an option and the impacted water will require treatment to achieve alternative reuse goals. Conventional mine impacted water treatment is successful in removing unwanted constituents but create brine and sludge that may require special handling or additional treatment, resulting in additional liabilities and costs. Freeport-McMoRan Copper & Gold has taken an approach to water treatment that focuses on transformation not concentration. The Water Treatment Test Facility located at Sierrita Mine has three test plants that are piloting the mine impacted water transformation process. Two plants have been designed for the removal of calcium and sulfate with products of gypsum and sulfur. The third plant removes metals from process water and transforms them into marketable metal sulfides. The transformation, rather than concentration, of mine impacted water solutes greatly reduce long term risks.

Feb 23, 2014

By B. K. Slone

The depth at which it becomes more economical to use slope access as opposed to box-cut access for near-surface coal reserves, termed "transition depth," can be established for a given coal property by considering cost estimates for those parameters that determine respective access method. Fourteen parameters that influence access cost were identified and ranges determined. A Transition Depth Formula was developed to permit determination of the better method of accessing a reserve, given such information as highwall slope, road width, total bench width, pit dimensions, road grade, belt component costs, pumping costs, and cost of overburden removal and reclamation. In most cases, in Appalachia, studies indicate that the transition depth ranges between 20 and 30 m.

Jan 1, 1998

At first glance the staid Joralemon background does not seem to equate with the life of adventure that irresistibly called me for over 70 years. But my ancestors had their adventures too. My father&apos;s family were Dutch Reformed Protestants who had energy or daring enough to come to America to escape the Catholic persecution that followed the Massacre of St. Bartholemew. The first Joralemon came from Friesland to New Amsterdam m 1636, just after Peter Stuyvesant. My father&apos;s mother&apos;s family, the Berdans, were French Huguenots who came to northern New Jersey only a little later to escape the Catholic domination in France. Some say that the first Berdan to come to America was given all the land between the Passaic and the Hacken-sack Rivers by King James. Whatever, the Berdan family settled there and was able to make a scanty living by farming and selling their produce in Manhattan. The spirit of adventure in my mother&apos;s family was just as tenuous. Gamaliel Beaman was pastor of a shipload of Puritans who came to Massachusetts in 1636. Gamaliel&apos;s descendents were peaceful farmers and some ministers in New England and later New York State. They had got all of the adventure out of their systems in the long and dangerous voyage across the Atlantic to escape religious persecution. The Joralemons and the Berdans married into families that had been in America almost as long as they had. On my father&apos;s side the Berdans, Doremus, DeGreys, Vanderbeeks, and Varicks showed by their names their Dutch or French Huguenot stock. The only one who achieved any fame was Peter Varick, who was George Washington&apos;s military secretary during the American Revolution. After this he was nine times mayor of New York and was one of the founders of Kings College, later Columbia University. He was responsible for one of my few ancestral claims to distinction. When the Marquis de Lafayette made a fare-

Jan 1, 1976

By J. L. Whitlock

A mutant strain of Pseudomonas paucimobilis is utilized to effectively degrade and or remove 90-98% of cyanide, thiocyanate, toxic heavy metals and ammonia from a cyanidation mill process and mine discharge maximum of 21,000 m3/d (5.5 MGD). Homestake Mining Company?s biological wastewater treatment plant has been in full scale operation for over 2 years at the Homestake Mine in Lead, South Dakota.

Jan 1, 1987