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By Chinmay Shingote, Robert Visintainer, Renjie Ke, Jaikrishnan R. Kadambi, John Furlan

Hydrocyclone separators are widely used in various industrial applications in the oil and mining industries to sort, classify, and separate solid particles or liquid droplets within liquid suspensions, which are considered to be multiphase systems. Numerous valuable studies have been conducted in recent years to investigate the flow fields inside hydrocyclones. However, much of the information regarding the performance of cyclones in the literature has limitations and much of it cannot be considered as completely applicable to most real-world applications; many of the studies investigated the flow fields within extremely simplified hydraulic designs that are not representative of the complex geometries or large sizes which are typical in industry. Therefore, in this study, the two-phase flow system inside the actual hydraulic geometry of a milling circuit hydrocyclone is explored with the aid of both computational and experimental techniques (particle image velocimetry (PIV)). More specifically, the flow field with an air core has been investigated. In addition, the air-liquid two phases flow in a hydrocyclone might cause some challenges on both the computational and experimental sides. Two turbulence models are utilized in the numerical calculations: the Reynolds stress model and large eddy simulation. The computational studies are mainly focused on the local flow behavior and the prediction of the dimensions and shape of the air core. Different section planes of hydrocyclone are selected as planes of interest and divided into several fields of view (FOV) for PIV measurements. Two-dimensional experimental velocity vector maps are obtained in each of the fields of view. The computational results are validated globally using pressure and flow rate readings at the boundaries and locally by comparison to the PIV velocity vector maps and profiles.

By Qingming Feng, Bo Huang, Dongbo An, Jinhong Zhang

A study of the application of mine tailings as precast construction materials through alkali activation was carried out, focusing on efficiently activating mine tailings, reducing alkali consumption, decreasing curing time and improving compressive strength. Test results showed that unconfined compressive strength of 40 MPa was achieved. In addition, to elucidate the geopolymerization mechanism of mine tailings, microscopic and spectroscopic techniques including scanning electron microscopy with energy-dispersive X-ray (SEM/EDX) analysis, Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) spectroscopy were used to investigate the microstructures and elemental and phase compositions of the reaction products. The findings of the present work provide a practical method for applying mine tailings as precast construction materials through alkali activation.

By G. P. JADAUN, ANINDYA PAIN, Aditya Rana, SAURAV RUKHAIYAR, N. K. Bhagat

This study compares three different techniques — decision tree, artificial neural network (ANN) and multivariate regression analysis (MVRA) — for predicting blast-induced ground vibrations in some Indian tunneling projects. The models’ performance was also compared with site-specific conventional predictor equations. A database consisting of 137 vibration records was randomly divided into training and testing sets for model generation. The results indicate that the decision tree is best suited to predicting vibrations. Furthermore, the decision tree suggests that the intensity of near-field ground vibrations is mainly affected by the total charge fired in a round, whereas the intensity of far-field vibrations is governed by maximum charge per delay and charge per hole.

By James L. Hendrix

This paper is intended to give the reader an update on the work being done at the Mackay School of Mines about the fate of cyanide on precious metals mill tailings waste. During the last two years several tailings impoundments have been sampled and analyzed for total and free cyanides. From our sampling program we are beginning to learn valuable information concerning the fate of cyanides in precious metals mill wastes. Included in this paper is a detailed description of our sampling and analytical techniques. Also, some of the data obtained from five sites are given.

Jan 1, 1986

By Adam Saylor, Travis A. Shoemaker, Steve Miller

Lidar scanning has become an increasingly popular tool for documenting underground excavations; however, high costs of traditional mechanical electrical lidar hardware, software, and training have limited the frequency at which lidar scans can be performed. Additionally, traditional scanning can be time consuming because multiple scan positions are necessary. With Apple’s incorporation of low-cost mobile solidstate lidar on select smartphones and tablets, lidar is becoming more tractable for everyday construction documentation similar to construction photo collection with smartphones. Here, we describe benefits of mobile solid-state lidar and describe several practical applications for use in underground construction, such as documenting the working face, over-blast, and geologic features of tunnels.

Jun 13, 2023

By John Batchelder

The Copper Canyon Cu-Au-Ag deposits include two geologically distinct hypogene ore bodies developed primarily in late Paleozoic rocks adjacent to a 38-m.y.-old potassic-altered granodiorite, whose emplacement seems to have been controlled largely by the Virgin fault, a north-striking normal fault. Widespread but subeconomic concentrations of sulfides as fracture and cavity fillings in skarn apparently preceded the final intrusion of the granodiorite. In the west ore body, metals reached ore-grade concentrations through the massive replacement of andradite by chalcopyrite, pyrrhotite, and pyrite mineral assemblages. The east ore body probably formed after the granodiorite reached its present level. Calculated 6dD values of water in equilibrium with primary and secondary biotites range from -76 to -99 per mil at temperatures indicated by d180 values from coexisting quartz and biotite. The lightest values are in secondary biotite from the east ore body. These data suggest that fluids associated with potassic alteration here were most likely composed of magmatic water mixed with some meteoric water.

Jan 1, 1976

By Yueyue Ding, Yuanhui Li, Zhengrong Li, Pengfei Yu, Kunmeng Li, Zhipeng Xiong

The stress evolution and failure characteristics of overburden were studied during multi-stope mining for a gently inclined thin orebody. Firstly, an indoor physical experiment was conducted on the excavation of a multi-stope mine with an orebody dip angle of 20°. The results show that the vertical stress concentration area gradually shifts to deep-buried rock mass with the mining from shallow to deep buried stopes, resulting in shear failure originating from high stress. On the contrary, the pressure relief zone presents an asymmetric distribution characteristic that is biased towards the upper part of the goaf, resulting in large subsidence and tensile failure of the stope #1 and #2 roofs. Secondly, the numerical simulation model under the same geological condition was established to measure the roof deformation at different stages of mining. The numerical simulation results are in good agreement with the physical test results; the roof displacement is largest in stope #2, second-largest in stope #1, and smallest in stope #3. Finally, the evolution of deviator stress concentration, displacement field and potential failure zone of overburden under different orebody dip angles were studied. As the dip angle of the orebody increase, the deep-buried stope roof changes from deviator stress release to deviator stress concentration in different stages of mining, and shear failure is most likely to be induced when the orebody dip angle is 30°. Meanwhile, the closure displacement of the stope roof decreases gradually, while the tangential displacement increases, so the anti-sliding ability of the support bodies in the stope should be improved. The potential tensile failure zone gradually shifts from the center of the goaf to the upper part, and the deep-buried stope roof evolves from tensile failure to shear failure. Results of this research expected to provide guiding significance for stope support design to control roof deformation and failure, to ensure the safety of the stope.

Mar 2, 2023

By William Gleason

The world has seen unprecedented economic changes in recent years, starting with the stock market collapse of 2008 and the great recession that followed. With these changes, the mining industry, like others, has been forced to find ways to adapt to the shifting and sometimes volatile conditions. It has been a bumpy ride that has not been easy. Prices for most commodities have been in a decline in the past several quarters ? albeit still well above the average prices of 10 years ago ? as the costs of production have been on a steady incline for the past 10 years. Adding to the concern was the report in April that China, which had grown at an average pace of 10 percent/year, for the past decade, slowed to less than 8 percent gross domestic product (GDP) growth this year, catching many off guard. Even gold, once the safe haven for investors during rocky times, stumbled in April of this year, losing 7 percent of its value in two days. So what?s an investor to do ? and how can companies still attract financing? For the first time in 10 years, SME, in conjunction with the New York Local Section of SME, attempted to clear the waters of the mining finance sector with a conference focused on ?Current Trends in Mining Finance.? Held at City University of New York, Graduate Center, April 29-30, the two-day conference attracted 148 attendees and was intended for senior executives and mining industry specialists, covering a range of important topics and trends through 17 panels with about 50 speakers. The presentations came from representatives from some of the most influential companies in the mining and financial sectors, including Citi, Nomura, Societe Generale, Caterpillar, Newmont Mining Corp., Ernst & Young, Export Development Canada (EDC), KPMG, HSBC, Tocqueville Asset Management, BNP Paribas, Revett Minerals, Royal Gold, Environ and ERM.

Jul 1, 2013

Miners really are an optimistic bunch. Even with the dark clouds hanging over the global industry, mining professionals still turn out in droves at industry conferences. In February, more than 7,200 professionals attended SME?s Annual Meeting in Denver, CO, a record. And the following week, more than 30,000 people converged on Toronto, ON, Canada for the Prospectors and Developers Association of Canada (PDAC) meeting. For many small and junior mining and exploration companies the PDAC conference is a place to find potential investors in their projects. The Investors Exchange attracts several hundred companies, each showing off their properties to the many money types who wander the hall during the four-day conference.

Jan 1, 2013

By Hun-Joon Sohn

Chemical metathesis and electrochemical reductive conversion of chalcopyrite in the presence of cupric ions were studied in sulfuric acid solutions for temperatures up to 90°C. The process results in the displacement of iron in the chalcopyrite lattice by copper ions with rejection of ferrous ions to the aqueous phase. The rate of reaction was found to be very slow, requiring subsieve-sized particles for extensive reaction to occur. The reaction was insensitive to copper ion concentration. Stirred ball milling of chalcopyrite introduces lattice strain. The reaction rate with strained particles was markedly higher than with annealed chalcopyrite. The reaction rate was found to be diffusion-limited, showing two distinct reaction stages corresponding to the formation of CuS (covellite) followed by Cu1.8S (digenite). The experimental activation energy for the first stage was 102 J (24.4 kcal) and the second stage 123 3 (29.4 -kcal) per mole. The rate-controlling process is diffusion of lattice ions, probably iron. The enhanced rate after milling is attributed to a recrystallization process which provides new paths for diffusion along dislocations and grain boundaries.

Jan 1, 1984

By J. M. Goris

The U.S. Bureau of Mines, in cooperation with the Homestake Mining Co., and the University of Utah, is conducting a field demonstration to evaluate the behavior of rock masses supported with cable bolts. One of two rock masses being studied is supported with both conventional and birdcage cables. This rock mass is located between the 6500 and 6650 levels of the 45-4BN stope. 21 ledge. The second rock mass is the hanging wall of the D-limb stope between the 3500 and 3650 levels near the Ross Shaft and is supported with conventional cables. The primary objectives of the project are to monitor the behavior of the two rock masses during mining using extensometers and cable support strain gauges, after which the rock will be modeled using the finite-element code UTAH III. Field data will be used to verify the modeling. In addition. a comparison between the effectiveness of conventional and birdcage cables will be made.

Jan 1, 1991

By Robert S. Lehto

Zinc concentrates received in La Oroya zinc refinery are marmatitic in nature, contain about 11% iron and traces of other metal values, Figure 1 shows the zinc circuit. The calcine from the roasted concentrates is leached in spent zinc electrolyte. Major part of the impurities is iron which has been oxidized to its trivalent form, This is the origin of the zinc leach residue for which the ZILERET process was developed and so named. The impure liquor from the leach is sent for purification and thence to electrolysis- zinc deposits on aluminum cathodes from which: it is stripped, melted and cast into slabs Typical assays of zinc calcine and leach residue are given in Table 1. Metal values contained in the leach residue, without counting any value of iron, amount to roughly $130 per short ton.

Jan 1, 1969

By Kanchan Mondal, Gopi Bylapudi, Anand Bhagwat, A. J. S. (Sam) Spearing

Corrosion of steel roof support systems can cause potential premature failure of the support, thus adversely affecting the excavation stability and rock-related safety. An in-house corrosion test system was designed and developed to test full-length roof bolts for material performance based on tensile load capacity and strength under different corrosive conditions found underground. Initially, ASTM A615 grade 60 steel roof bolts, which are the most commonly used bolt material in the United States, were tested with and without stresses in a simulated underground coal-mining environment for approximately six months. This paper mainly discusses the test system, protocol and system shortcomings, and makes recommendations based on the observations and results.

By Albert F. Duzy

Recently there have been some problems associated with hot coal in shipments from the USA to overseas markets. This paper will serve several functions. First, a brief review is presented, together with a selective bibliography. Second, a thorough discussion of coal oxidation is covered. Third, potential effects of storage are presented and, lastly, methods are suggested for the safe storage and bulk transfer of coal. The scope includes coal storage for power plants.

Jan 1, 1983

By E. Allen Hendt

It is a pleasure to be invited to speak before a gathering of executives representing America's leading mineral companies, I welcome this opportunity, particularly because it comes at an important period in the development of U.S. commodity policy. This morning, I discussed our general commodity policy primarily in the. Context of the north-south dialogue between developed and developing countries. This afternoon, I would like to focus more specifically on potential cartel activity and U.S. mineral import dependence.

Jan 1, 1978

By C. Hanson

Two modes of potential loss of oxime extractants in liquid extraction processes for the extraction of copper have been studied. In loss "by chemical degradation, two mechanisms of acid hydrolysis are possible, some reagents degrade primarily in the organic bulk phase, Others at the interface between the organic phase-- phase protects the oxime but salts added to the aqueous acid phase can promote the rate of degradation. The reagents reported on are the LIX series (Henkel Cpn), SME529 (Shell Chem.Co.) and P5100 (Acorga) Loss by organic entrainment in the aqueous phase leaving mixer-settlers has also been studied, parameters investigated including impeller/tank geometry and the phase inlet arrangements. The consequences of extractant loss by the above mechanisms...are commented upon. They include the direct economic cost, the possible environmental problems and the implications for downstream operations such, as electrowinning.

Jan 1, 1980

By William R. Nash

Case histories of water problems in underground mine shafts and tunnels are outlined to illustrate varying degrees of sophistication in grouting techniques currently applied in such construction. The interception of water underground can be one of prior knowledge, i. e., the site investigation provides necessary data to plan a grouting program prior to construction start, or excavations may encounter "changed conditions" or unplanned water. The latter includes catastrophic inflows and emergency situations where the structural integrity of a building or concrete shaft lining are jeopardized. The presentation of this paper outlines some applications of grouting work in underground mine construction throughout the United States in a variety of geological provinces and for a variety of minerals.

Jan 1, 1984

By E. L. Piper

Natural graphite has been known for many centuries, having first been reported as a distinct mineral form by Gessner in 1565. At that time, graphite was used extensively as pencil "lead" because of the ease with which it marks paper. It is a black, unctuous material found as flakes, lumps, or needles in scattered locations throughout the world. The less crystalline, or "amorphous", natural graphites are thought to have been formed from coal under conditions of high temperature and pressure. The more crystalline varieties, such as those mined in Ceylon, probably were precipitated from molten solutions or were pyrolyzed from gaseous carbon compounds. Recognition of the good thermal and electrical conductivity of graphite, together with its highly refractory nature, led to an increasing number of appli¬cations for this material. Clay and pitch bonded natural graphite has been used in crucibles, refractories, foundry facings, and other high-temperature appli¬cations. These forms constitute the most important current uses for natural graphite in the United States. Other products containing natural graphite include batteries, lubricants, pencils, brake linings, etc.

Jan 1, 1973

By AK Raina

Blasting is used in mining and civil excavations to break the rockmass for ore production or creation of space. One of the disadvantages of the method is that it causes breakage beyond the proposed excavation lines. Pre-split is used to control such breakage in rockmass. This paper introduces the use of digital image analysis technique (DIAT) to measure rock breakage and half cast factor (HCF%). A new factor, undamaged area (AUD%), is introduced to improve the prediction, owing to the shortcomings of the HCF%. A comparison of significant data of AUD% and HCF% showed that HCF% has a lacuna of overpredicting, whereas AUD% can be used effectively to address the issue. Artificial neural networks are used to solve the complexity of multiple variables involved in predictions and to ascertain the importance and sensitivity of such variables in prediction regimes. This method will help users to evolve blast-induced damage objectively. A comprehensive scheme of things for future developments is included, which can be helpful to researchers in defining their research in this area.

By Yuting Xue, Mark Van Dyke, Zoheir Khademian

Borehole scoping has been widely used in the U.S. underground coal mines as a method for geologic mapping and stability analysis because it is very useful for identifying rock types, voids, fractures, and formation boundaries through the direct observation of the borehole wall. An image stitching technique was proposed to generate panoramic borehole images from side-view borescopes in a previous study. However, the generation of panoramic borehole images can be affected by the borehole condition because the image stitching process highly depends on the key point detection and matching. The presence of dust and water could have a significant influence on the detection of key points. In this study, the influence of borehole conditions on panoramic borehole images was studied from the success of image stitching and the visibility of geologic features and lithology changes. Borehole videos recorded at different times, when the same borehole was freshly drilled, freshly washed with water and 12 days after washing, were processed with the proposed technique. The comparison of the stitched images shows that the presence of dust has minimal influence on the image stitching process but shows significant negative effects on the visualization of geologic feature and lithology change. In addition, the presence of water can significantly hinder the image stitching process, which in turn helps in identifying lithology change. Borehole scoping aids in identifying and mitigating hazardous conditions in underground mines, and this study provides preliminary inputs into identifying optimum borehole conditions for geologic mapping with panoramic borehole images.

Feb 1, 2025