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By S. Goodfellow, J. C. Ordóñez-Calderón, K. Esmaeili, N. Houshmand

A good understanding of the hardness of ore being handled and processed in a mining operation can significantly improve operational efficiencies by providing valuable data to support decision-making through the mining value chain (drilling, blasting, comminution). This study presents the results from the application of Machine Learning (ML) to predict rock hardness using various geophysical and geochemical features. Core samples from a mine site were logged using a multi-sensor core logging system. Measurements including ultrasonic p-wave and s-wave velocity, elemental concentration via portable XRF, and Leeb Hardness, were measured every 2 cm along the length of the core. The ML model was set up to predict the Leeb Hardness using the elemental concentrations and ultrasonic velocities as predictors. The Leeb Hardness values were grouped into three bins and used as a classification target for the ML models. Various ML models, including linear regression, support vector machines, decision tree, XGBoost, Random Forest, K-Nearest Neighbors, and Naïve Bayes were tested. The model performance demonstrated that the Random Forest and XGBoost models produced the highest accuracy of 74-91%. Random forest and XGBoost were then selected to perform regression models to estimate a Leeb hardness value rather than a hardness class. These models were able to estimate the Leeb hardness value by 4.57-4.87 % error.

Mar 2, 2022

By Michael Cruickshank

All life on Earth relies on the ocean and yet the ocean is 95 percent unexplored, unknown and unseen by human eyes,? said Paula Keener, director of education programs for National Oceanic and Atmospheric Administration?s (NOAA) Office of Ocean Exploration and Research. ?To better understand, manage and protect the ocean and its resources, NOAA believes it is critical to use the best technology to explore, discover, inform, educate and motivate? (MTS, newsletter, January 2011). In the last few decades, our understanding of the global mineral resource base has been drastically changed by some surprising new developments. The potential for commercial minerals per unit area in the oceans and seabed appears to be similar to that of the terrestrial lands. Thus, almost three-fourths of the global mineral resources are in, or under, the sea and are virtually undeveloped. The area of the Pacific seabeds alone is greater than the total area of the global lands. Half of the global seabed minerals are now controlled by nation states within their Exclusive Economic Zones (EEZ). The other half is controlled by the United Nations (UN) through the International Seabed Authority (ISA) within the ?areas beyond national jurisdiction? known as The Area. Thus, the Law of the Sea, ratified in 1994, has resulted in the largest transfer of control of natural resources in the history of mankind. This paper was prepared by the Society for Mining, Metallurgy and Exploration (SME) Committee on the Offshore Technology Conference for the SME Board of Directors and other interested parties. As the premier professional society for the mining and mineral community in the United States, with a history dating back to the 19th century, SME?s mission is to encourage and support young men and women engineers in the minerals industry, provide the services they need, improve the image of the industry, strengthen the networking among global industry professionals and engage in proactive collaboration among industry, government, academia and nongovernmental organizations (NGOs). The accomplishment of this mission can be strongly advanced by highlighting what is probably now the most significant development in the history of the modern minerals industry - the exploration of the marine environment and the understanding of the potential for the development of the minerals therein.

Jan 1, 2011

By P. A. Cornejo

Blastings always generates induced vibrations through seismic wave, these are lost energy from the blasting and therefore causing the disturbance of slopes and structures near the blast source. Most of the components of an open pit mine have to reach a physical stability, especially during its closure process. Aiming to develop a vibration prediction model using the historical records from an open pit mine located on Peru, this research has two main focuses depending on the distance from the blast source to the structure: to protect the final slopes and to protect the villagers houses. Both are based on the Devine model of the Square Root Scaled Distance (SRSD) to predict the Peak Particle Velocity (PPV). The Mid field model, where is found mainly final slopes from the pit, limited by the failure criteria of McKenzie based on the geo mechanical properties of the rock mass. The Far field model ranges distances where are located the most community households, limited by the German rule DIN 4150 for highly sensitive structures. Both scenarios resulted on a distribution abacus to limit the weight of used explosives to get the best operational advantage and structure safety.

Mar 2, 2022

By E. R. Bauer

A primary goal of Ground Control Research, Bureau of Mines, U.S. Department of the Interior, is to develop information that can be used by the mining industry to reduce accidents and fatalities due to failure of mine roof. A specific research objective is to determine methods to detect hazardous coal mine roof. This paper reviews the existing and experimental techniques, and describes a recent Bureau of Mines contract research project that resulted in a simple technique and prototype instrument for evaluating mine roof competence.

Jan 1, 1986

By M. C. Mound

A recent development using XRD techniques, a unique fixed detector, specifically permitting full mineralogical information simultaneously for the first time, specially designed sample preparation and presentation system and Rietveld codes provide a continuous real- time analysis on the true contained mineral polymorphic composition of powder streams such as ore materials, cement, ground clinker or any other mineral stream conducive to XRD analysis. There are several COSMA systems currently operating in the US, Canada, Italy and Australia, proving service and reliability of this concept. The mineralogical information generated continuously in real time is used for automated efficiency, product quality and reduces costs. Quantitative Phase Analysis information is transmitted to the plant DCS via Modbus over RS422 or ethernet. Some limited information is stored in the on-board computers for optional future use at the operator?s option.

Jan 1, 2010

By M. Nambiar

Due to the remote locations of mining projects and the need for long transmission lines to provide electrical power, mining sites often operate with poor network power quality and low short-circuit capacity. To cope with this situation, more and more mining operators are considering the installation of appropriately designed synchronous condensers together with power factor correction and harmonic filter systems (PFC & HFS). The installation of such power quality equipment is viewed as a technological advancement in the mining application. An adequate level of short-circuit power is essential and has to be ensured for the safe and reliable operation of especially large cycloconverter-driven gearless mill drive systems (GMDs) used for grinding. This paper explores the impact, technical advantage and reasoning for the selection of this advanced hybrid technology to cope with the power system challenges of future mining projects. It also delves into the potential problems and how to address them.

By Peikun Liu, Guangyu Sun, Raja V. Ramani, Shambhu Sharan, Raman Srikanth, Bharath K. Belle

The contribution of the various outby sources to the contamination of the panel intake air has been the subject of a relatively small number of studies. In this paper, after a brief review of past studies, results from recent experiments on rates of contamination of intake air by outby dust sources are presented. Present study indicates that each outby source by itself may not be a major contributor. The loading point in the continuous miner section did not appear to be of major concern from contamination point of view. Belt entry including transfer point contributes significantly to the intake air dust level, though reentrainment was not a major source of dust. In longwall panels, the stageloader-crusher was the most dominant source. The panel-to-main belt transfer point was not a major source. Taken collectively, the contribution of all outby sources can be significant. In one longwall section, at the beginning of the longwall face, the contribution of all the outby sources and the headgate cut-out operation was observed to be about 80% of the permissible exposure limit (2 mg/m3). In modem high production longwalls, the application of effective dust control measures to reduce the dust generated from the outby sources is essential to achieve compliance with the dust standards.

Jan 1, 1997

By A. H. Srnallbone

Over the past few years the rising production costs, shortage of skilled labor, and increased use of lower grade ore bodies have all added justification for the use of on-stream analysis. A rise in the number of on-stream units indicates that this type of assay is now being accepted as a necessity. On-stream analysis is a much more rapid means of obtaining true assays of a flowing product when compared to wet chemistry or "grab" samples dried, briquetted and assayed by x-ray. In contrast, on-stream analysis uses real time samples assayed every 30 seconds while each stream is assayed every 5 to 15 minutes. It is very important not only to know that a change has occurred in the process, but to know what caused the change and how to correct for the change. For example, in a tailing sample the elements of interest comprise between 1% and 10% of the sample. The remainder is water and gangue. Previously the gangue was not assayed nor were the low atomic number elements used for corrections. In addition to the demand for higher accuracies some concentrators were being penalized for excessive Ca or in some cases 5i in their concentrates. This penalty was being imposed by the smelter in order that they could better cope with pollution problems and prolong the life of their furnaces. But until Ca, 5i, and S are measured on-line, nothing can be done about their control. By accurately measuring these light elements on-line, a complete assay is obtained of the total sample providing improved accuracy for the important products. The justification for complete accuracy assays is now even more obvious because they are possible at very 1ittle increased cost and at no increase in analytical time.

Jan 1, 1977

By E. M. R. Santos

Acid mine drainage (AMD) is a serious environmental problem in mining activities. Prediction is the first step for evaluate the potential of acid generation and there are some possible methods to estimate it. They are described as static tests, which examine the balance between acid producing and acid consuming materials, and kinetic tests, which attempt to predict drainage quality over time. Static methods are very simple and give a qualitative classification of the ores based on their potential to generate acid drainage. The characterization of ores to determine their acid producing potential is vital for the prevention of long term environmental liabilities. Laboratory tests were conducted under different methodologies to predict the acid producing potential of sulphide overburden, ore materials and tailings from a deposit of copper ore.

Jan 1, 1999

By Bobby Michael (Mike) Roberts, G. M. (Mike) Bernard, Ronald R. Kelly

This paper describes Cananea's successful implementation of the world's first mobile high angle conveyor (MHAC™) to achieve multiple-lift stacking of their primary crushed (2,500 mtph) low-grade ore. The mobile high angle conveyor answered Cananea's needs to stack a second lift, 30-meter high, on their Quebalix I pad. The mobile high angle conveyor is a custom unit that was designed by Terra Nova Technologies (TNT) in conjunction with Continental Conveyor and Equipment Company (CCE's 100th HAC). The stacking system expansion project also includes a rail mounted tripper on the existing overland conveyor and a custom designed "corridor conveyor" to build the corridor for the upper mobile HAC tracks and tail of the existing mobile stacking conveyor. Mexicana de Cananea, part of Grupo Mexico, is a large copper producer in Sonora Mexico and has been in operation continuously for over 100 years.

Jan 1, 2002

By A. Porvali, V. Agarwal, M. Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2•H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can be treated further with NaOH solution to form REE hydroxides. This study focuses on metamodeling of a simulated flowsheet with design of experiments (DOE). Based on literature survey, a process flowsheet was developed using HSC Sim software. The created flowsheet focuses on circulation of solution containing Na+, K+, SO42- ions and impurities liberated in the NaOH treatment of double salt precipitate. The effect of seven parameters (P1-P7) on seven responses (R1-R7) were modeled using central composite design (CCD). INTRODUCTION Nickel metal hydride (NiMH) battery waste can be considered as an urban mineral due to the presence of valuable metals like: Ni, Co and rare earth elements (REE) (Larsson et al., 2013). In NiMH battery waste leaching experiments, sulfuric acid has often been employed as a lixiviant (Pietrelli et al., 2002,Zhang et al., 1999,Rodrigues and Mansur, 2010,Porvali et al., 2018). The key advantages of sulfuric acid are its stability and cost-effectiveness compared to other mineral acids such as HCl and HNO3. However, the usage of sulfuric acid in NiMH battery waste leaching poses simultaneous challenges and advantages. Limited REE solubility can be taken as benefit when recovering REEs double sulfates after solid-liquid separation. However, sodium and potassium hydroxide, present in electrolyte residues in the battery waste, can cause in-situ precipitation already during leaching due to limited solubility, thus decreasing the total REE recovery (Porvali et al., 2018). However, this problem can be circumvented by washing the electrolyte residues off the raw materials. Subsequently, the REEs may be precipitated in bulk as a mixed double salt out from the solution at very low pH with minimal co-precipitation of Ni and other metals. This relatively easy separation method can be extremely advantageous in the case of such a complex solution matrix with relatively high REE concentrations (conc.). Once REEs have been precipitated as double sulfates as per eq. (1) (Porvali et al., 2018), the resulting double salt precipitate lacks applications without further treatment. Direct thermal treatment would generate sulfur dioxide emissions and likely require high temperatures in order to transform double sulfates into REE oxides. Furthermore, the precipitate contains Na ions, which would need to be removed by chemical treatment from the calcined REE product. In the context of circularity of raw materials, it can be taken of a remarkable benefit if the sodium and sulfur present in the double salt could be reused instead of wasting them into the side streams. To that end, in this simulation study, the double salts are converted by dissolution and precipitation to hydroxides which are readily treatable, e.g. with total dissolution and solvent extraction, for further purification (Abreu and Morais, 2010):

Jan 1, 2019

By J. Bilant, B. Carlson, N. Gow

High Pressure Grinding Roll (HPGR) technology has been evaluated to replace tertiary cone crushing at Coeur Rochester operations (Coeur Rochester, Inc.) as an opportunity to improve silver recovery. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact of metallurgical recovery and heap leach performance of crushed product generated by an HPGR. In 2018, Forte Dynamics evaluated the HPGR laboratory metallurgical data from Coeur Rochester and all third parties to develop field-scale leach curves based on new crushing scenarios. The laboratory recovery test work data was consolidated and scaled to field conditions to determine projected heap leach performance. Based on the metallurgical testing conducted, the replacement of current tertiary cone crushers with HPGR technology has the potential to increase Coeur Rochester’s silver recovery rate by 8%, from 61% to 69%, and shorten the overall timing of silver recoveries from 20 years to just over two years. INTRODUCTION The Rochester mine, and associated valley fill heap leach facilities is an open-pit silver and gold mine located in Pershing County, Nevada, approximately 26 miles northeast of the city of Lovelock. In 2017, Rochester produced approximately 4.7M troy oz silver (Ag) and 51k troy oz gold (Au). Ore mined at Rochester is either fed directly to the primary X-Pit crusher, crushed at an in-pit crusher system, or placed directly onto a heap leach pad as run-of-mine (ROM). Both crushing circuits are comprised of three stages of crushing to produce a nominal 3/8” ore. Primary crushing consists of jaw crushing while secondary and tertiary crushing are composed of varying cone crushers. Historical recovery rates of crushed Rochester ore average 61.4% Ag and 95.9% Au over a period of 20 years [1]. These rates were derived from third party verification of in-house metallurgical test results, crusher production and heap leach production results from 1986 through 2004 in a private report for Rochester produced by KD Engineering Co., Inc. Recovery rates are regularly verified by compositing daily samples of ore delivered to each leach pad from the X-pit crusher, in-pit crusher, and/or ROM. A proportionate split of each sample is used to generate monthly composites for metallurgical analysis utilizing column leaching and bottle roll leaching. These tests are run in a manner analogous with production conditions and deliver test results that provide expected heap leach performance. As the Rochester oxide deposit has been mineralogically and metallurgically consistent, the gold and silver recovery trends have also been consistent over the life of the project. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact of HPGR technology to metallurgical recovery and heap leach performance of crushed product in an open circuit configuration, as a potential replacement for the currently in place tertiary cone crushers. During these years, HPGR was evaluated in three phases of test work.

Jan 1, 2019

The implementation of NAFTA in January of 1994 was expected to have small but beneficial effects for the Mexican economy, mostly through increased investment flows. Mexico's mining industry was especially likely to benefit, as mineral investment funds would be diverted to the now safer Mexico and away from similarly endowed but more risky Latin American mineral economies. The results of the past two years have shown that it is governments and macroeconomic factors that influence investment flows, rather than the fine-tuning of trade flows through so called "free-trade" agreements.

Jan 1, 1996

By George K. McCord

It is a pleasure to participate in this Fall meeting of the Society of Mining Engineers to discuss energy conservation trends in the cement industry. Energy is the "life blood" of American industry, and the ability to use available energy resources efficiently may well determine the future of our nation and of its industries. The Federal Energy Administration has classified cement manufacture as one of several energy-intensive industries in the U.S. and has selected the Portland Cement Association to make a detailed study of possible energy conservation measures. Member companies of the Portland Cement Association represent about 85% of the cement producing capacity of the United States and 100% of Canadian capacity. Stated briefly, the purpose of the Association is to extend the uses of portland cement and concrete through research and development, market promotion, education, and public affairs work. PCA's general offices and research laboratories are located in Skokie, Illinois. Our staff of engineers, scientists, and research personnel make the PCA uniquely qualified to perform an energy conservation study of the kind requested by FEA.

Jan 1, 1975

By Bo Hyun Kim, Mark K. Larson

Fault-slip bursts induced by mining activities can result in severe damage to nearby mine development. In general, engineers designing rock support in burst-prone mines not only need to consider stress redistribution resulting from excavation, but also dynamic loading that results from seismic waves generated by large mininginduced fault-slip events. In this study, we simulated dynamic waves in sedimentary rock from a blasting source and from a mining-induced-seismicity source using a Universal Distinct Element Code (UDEC) model with discrete fracture networks (DFNs). Our purpose was to investigate the stability of openings and the adequacy of existing support systems at an underground limestone mine in South Korea. A baseline model with only static loading was also simulated, which verified observed stability under such conditions. The results indicate that the current support system of shotcrete lining is likely to work well under dynamic loading caused by blasting. However, when the dynamic source was a far-field fault-slip event, the dynamic loading exceeded the support capacity of the shotcrete lining. Thus, if a mine is operating in ground with an elevated risk of mininginduced fault slip, mine engineers should consider seismic wave propagation and ground motion distribution from a remote, mining-induced fault-slip event to determine a suitable support design.

Jul 1, 2023

By Francesco Chiappalone, Franco Gasperin, Fabrizio Fara

This document describes the challenging task of mining through tiebacks using a 21'-8" diameter Tunnel Boring Machine (TBM) as part of the Ship Canal Water Quality Project. The mining operation involves navigating through 17 tie-backs that are evenly spaced at 8-foot intervals, with many intersecting the full face of the cutterhead. Detailed analysis and review of TBM parameters specific to this area have been conducted to ensure operational efficiency and safety. Hyperbaric interventions have been planned and coordinated, encompassing pre-mining preparations, continuous monitoring and adjustments during the mining process, as well as post-mining measures. The document highlights the complexity and importance of strategic planning and execution to successfully overcome the tie-back intersections during the mining operation.

Jun 23, 2024

In phosphate flotation, more than 90% of the finer fraction (-35, + 150 mesh) is recovered as opposed to 70% of the coarser material (-16, + 35 mesh). On the other hand, coarser fraction is higher in phosphate content than the finer feed. Consequently, improvement in the coarse recovery is highly desired. It was determined on bench scale that emulsification of the collector (fuel oil and fatty acid mixture) can lead to enhanced recovery of coarse particles. Flotation of phosphate with emulsified collector resulted in improved recovery and grade also on the plant scale.

Jan 1, 1992

By Elnaz Saminfar, Jae Bateman, Eric Westergren, Mark Trim

This paper presents a case study of two major Australian infrastructure projects that used digital engineering to facilitate design delivery: WestConnex Project (Rozelle Interchange), and Sydney Metro West (Eastern Tunnelling Package). The paper presents project overviews and building information modeling (BIM) execution and focuses on modeling techniques, software utilization, data management strategies and how the digital models helped the design-build team mitigate impacts to schedule by identifying clashes between disciplines before the execution of work. Finally, it demonstrates the positive and transformative impact of digital engineering on the design and construction of large underground infrastructure projects and highlights its role in asset management throughout the project lifecycle.

Jun 23, 2024

By Syd S. Peng

According to accident statistics (l, 2), roof fall accidents occur quite frequently at the intersections of underground? openings and account for up to 30% of the roof fall fatalities. But this figure will certainly go up considerably if roof falls not associated with any fatal accident are included in the analysis. Unfortunately, nonfatal roof falls are seldom documented. In the underground coal mines, there are two types of entry intersections. One is the three-way (V type) and the other is the four-way (T type) intersections. A three-way intersection occurs whenever the mainline track haulageway turns at an angle into a section haulageway. The four-way intersections by far the most common type in the U.S. under-ground coal mines are formed by the intersections of two entries which are oriented perpendicular to each other or by the intersections of entries and crosscuts. However, crosscuts are frequently driven at an angle to the entry to facilitate machine movements. The four-way intersections formed by this method of crosscut development are angled. At the intersection of two underground openings, the diagonal roof span is wider than the width of each individual opening. This is one of the major reasons why roof falls occur more likely at the intersections than in the entry between pillars. Consequently, special intersection support plans are usually employed (Figs. 1 and 2) for intersections. The most popular practices are to decrease roof bolt spacing 1 ft. less than or to increase roof bolt length 1 to 2 ft. longer than those employed in the entry between pillars (3). The increase in bolt length or decrease in bolt spacing can be applied to all of the bolts in the intersection or employed only for the strategically located bolts depending on the individual mine practices. These rather generalized practices seems to be adequate for some areas but in many cases inadequate for others. Occasionally, the neighboring two lines of chain pillars are staggered such that the crosscuts in one row of chain pillars face the centers of the chain pillars in the neigh-boring rows. This layout forms T-type three-way intersections which are also inadequate for most weak roofs (3, 4). A study was therefore initiated to develop special techniques for intersection supports. The first phase of the study was the analysis of the stress fields for the underground entry intersections. A three-dimensional stress analysis was necessary for this purpose. Unfortunately, the three-dimensional problems of complicated boundary conditions are beyond the existing analytical methods. The three-dimensional finite element method (FEM) was therefore employed in this study. In the analysis, square pillars of 40 feet wide and an entry height of 8 feet were assumed while entry widths varied at 14, 20 and 26 feet. This model was selected to simulate the mine where roof falls data were collected. The second phase of the study was the collection of field data. The sizes of the roof falls including heights, lengths and widths were collected and analyzed. In the third phase study, the results of the first and second phases were compared and discussed. The analysis of field data revealed an arching zone within which roof falls occurred. The arching zone above an entry obtained empirically was compared with the calculated stress contours. Assuming that the bolts must be anchored in the rock strata outside the arching zone, the preferable systems of bolting were proposed. Also the amount of pretension required to inhibit sliding between layers was discussed.

Jan 1, 1978

By J. J. Kellar

Researchers have long speculated regarding the adsorption state of collectors on mineral surfaces. Only recently have analytical techniques become available which allow direct in-situ analysis of adsorbed layers. Fourier transform infrared spectroscopy coupled with internal reflection spectroscopy (FT-IRJIRS) with reactive internal reflection elements allows for unobtrusive investigation of the adsorbed layer (Harrick, 1979). This technique has been used both for the in-situ identification of adsorbed species and for the direct calculation of collector adsorption density in real time from infrared spectral data (Miller and Kellar, 1988). The reactive mineral IRE serves both to internally reflect the infrared light and to act as a substrate at which collector adsorption can be monitored. Shown in Figure 1 is a schematic of light being internally reflected in an IRE. As the light is totally reflected at the interface, an evanescent wave propagates a short distance (typically a few microns) away from the IRE, and sampling of the interfacial region occurs. Because of multiple internal reflections, great sensitivity can be obtained. Flotation systems for which this method has been demonstrated include CaF2/oleate, Al2O3/ dodecyl sulfate, CaCO3/oleate, ZnS/xanthate, and KCl/octylamine (Miller and Kellar, 1988; Kellar et al., 1989, 1990; Miller et al., 1990).

Jan 1, 1992