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By Felicia F. Peng

Employing the combination of two types of polyelectrolyte might become necessary to enhance both settling rate of the flocs and water clarity of fine particle suspension in high capacity thickening process. The sequence of addition, mixing, type and dosage of polymer affect the overall performance and capacity of a thickening process. For the sedimentation of copper flotation tailings, the cylinder test results showed that two different techniques may be used to achieve the required performance including high settling rate of flocs, underflow density and overflow water clarity, by either adjusting pH prior to anionic polyelectrolyte flocculation, or using a combination of polymer flocculant and coagulant (dual polymer system). The dynamic thickening testing results showed that only the approach using a dual polymer system is able to meet the required performance. The effects of polyelectrolyte dosage, the sequence and numbers of polyelectrolyte addition, feed concentration, bed level and rake speed on the settling rate, underflow solid, and water clarity were studied in cylinder test and a laboratory dynamic thickening unit with various conditions related to the thickening process. The dynamic test is especially valuable in evaluating the addition and mixing of polymers. The results were evaluated quantitatively, using total suspended solids in supernatant, underflow density and capacity per unit settling area per unit time as the measure of effectiveness. The objective of this study is to quantify and explain some of the parameters involved in the sedimentation of copper flotation tailings.

Jan 1, 1997

By W. Z. Choi

In our previous work, a population balance model describing the simultaneous processes of size reduction and mineral liberation has been developed. The experimental verification of this model, however, has been limited to a binary mineral system containing only one composite particle class. When considering multiple classes of composite particles, the estimation of model parameters becomes much more difficult. In the present work, a procedure for estimating model parameters for a multiple composite class model has been developed. Emphasis is placed on the direct experimental determination of these parameters. The physical significance of the breakage rate function and the liberation function in characterizing the liberation process is also discussed.

Jan 1, 1987

By J. Richard Kyle

The Pb-Zn ore bodies in the Pine Point district are localized in paleo-solution structures that developed as the result of post-middle Givetian subaerial exposure of the carbonate barrier complex. Sulfides are concentrated in transgressive pale-solution structures that acted as natural bypasses between aquifers and loci for mixing of fluids of different character, one of which contained metals and the other reduced sulfur. Complex ore textures indicate rapid early sulfide precipitation followed by slower sulfide growth. Evidence for both sulfide-carbonate equilibrium and disequilibrium conditions suggest fluctuations in ore fluid composition. District and ore body metal distribution patterns may reflect the nature and movement of mineralizing fluids.

Jan 1, 1979

By Lon Santis, Gregory M. Rumbaugh, Christopher Mark

This paper examines the relevant theory, experience, and past practices relating to development mining near gas or oil wells. It addresses setback distance for both coal and stone room-and-pillar mining. This study also involved a review of accident reports involving well interceptions and downhole well surveys. It provides technical considerations for decisions regarding safe setback distances for development mining throughout the United States. The study’s scope is limited to mining near active or inactive (i.e., non-producing, abandoned or inadequately plugged) wells with known surface locations.

Jun 25, 2024

By Abhishek Kumar, T. G. Sitharam, Surender Singh

The height of tailings pond (TP) embankments is frequently raised to accommodate the ever-increasing volume of tailings released by the mining industries. Excess pore water pressure (EPWP) may develop during the height-raising operations, which can affect the overall stability of TP. This article presents a detailed stability analysis for the embankments of an existing TP, the height of which was increased twice utilizing downstream (D/S) and upstream (U/S) construction techniques. A rigorous two-dimensional transient fully coupled-stress-pore pressure analysis is performed in the finite element-based package RS2 to examine the build-up of EPWP during different stages of construction. Furthermore, an attempt is made to investigate the feasibility of future height raising, with due consideration given to the influence of embankment raising rates. Results from the analysis show a development of higher EPWP within the tailings deposit in comparison to the embankments of TP, indicating the development of an undrained-like condition. The study further reveals that the development of EPWP is highly affected by the rate at which embankments of TP are being raised. A higher rate of embankment-raising results in the development of greater EPWP in comparison to a lower embankment-raising rate, which may lead to the ultimate collapse of TP. Furthermore, based on the stability analysis, the height of existing TP can be further raised by 4 m (two lifts of 2 m height) utilizing the U/S construction technique. A thorough cost and benefit analyses are however required before implementing the results of the current analysis since the storage capacity of TP is reduced while raising by the U/S method.

May 16, 2023

By David Mast, Irwan Halim, Brian Hagan, Kaveh Talebi, Jason Edberg, Amanda Foote

On June 14, 2023 Jay Dee Contractors’ Tunnel Boring Machine (TBM) “Phoenix” holed through and completed mining the second drive of the I-75 Segment 3 Storage and Drainage Tunnel. Completion of the tunnel came only after overcoming several challenges, including a groundwater intrusion event which deposited thousands of cubic yards of wet ground material into the tunnel. This paper will discuss the events which delayed completion of the tunnel by over nine months, the risk management and construction approaches assumed by the Design-Build team during bid, several challenges faced by Design-Build teams when building stormwater resilience tunnels using traditional Department of Transportation standards, and recommendations for improving risk allocation and proposal documents for future similar Design-Build tunnel projects.

Jun 23, 2024

Flooded-bed scrubbers on continuous miners have been shown to be an effective respirable dust control technology, traditionally used during the extraction of extended cuts of up to 12.2 m (40 ft). To effectively use scrubbers in faces that employ exhaust ventilation, the return ventilation curtain or tubing should be located outby the scrubber discharge on the continuous miner, which results in a setback distance from the face of approximately 12.2 m (40 ft). The goal of this research was to compare respirable dust levels generated in 6.1 m (20 ft) cuts when using extended curtain setbacks with a scrubber operating to dust levels in 6.1 m (20 ft) cuts when using traditional exhaust face ventilation without a scrubber operating. Dust surveys were completed at three mines with area and personal sampling conducted to quantify respirable dust concentrations on a cut-by-cut basis. Sampling results did not show a statistically significant difference in respirable dust at the continuous miner or shuttle car locations with and without the scrubber operating. However, with the scrubber operating, respirable dust concentrations in the return airstream downwind of the miner showed reductions of 91%, 86%, and 40% at Mines A, B, and C, respectively. The reductions at Mines A and B were statistically significant. Likewise, reductions in respirable quartz dust levels in the miner return were observed at all three mines, with statistically significant reductions of over 80% observed at Mines A and B. Consequently, operation of the flooded-bed scrubber did not impact respirable dust levels in the face area but did significantly reduce respirable and quartz dust levels downwind of the continuous miner. These results were obtained with the mines operating at or above the minimum operating levels specified in their ventilation plans.

Feb 23, 2014

By Isabel F. Barton, Matthew J. Gabriel, CARSON ROBERTS, JOHN LYONS-BARAL, LEON DUPLESSIS, Mark D. Barton

Geometallurgical assessment of orebodies in the mining industry typically relies on bench-scale or lab-based characterization techniques. In this study, we investigate drone- and tripod-based field hyperspectral imaging as a potential addition to the geometallurgy toolkit in multiple applications. This pilot study tests hyperspectral imaging for largescale mineral mapping in and around the active Lisbon Valley copper mine, including natural exposures, previously producing U-V mines, highwalls, dumps, and leaching sites. Tests include different (supervised and unsupervised) mineral data classification methods, varying mineral spectral reference libraries, comparison with ground-truth geological and spectroscopic mapping and sampling, and integration with LiDAR data. The results show that hyperspectral scans can produce spatially registered maps of the distribution of different spectrally active mineral types over dumps, highwalls, leach pads, and natural outcrops. Clays, other phyllosilicates, carbonates, and sulfates showed up particularly well. The sensor was also able to distinguish dry from lixiviant-saturated areas and map different clay types on the leach pads, and shows promise for differentiating types and health of vegetation. These results suggest that hyperspectral imaging, if coupled with robust ground-truthing, can be a useful complement to existing geometallurgical techniques in the mining industry, such as geological mapping, blast hole sampling and automated mineralogy identifications, and handheld spectrometry. In particular, hyperspectral imaging has promise for mapping the distribution of acid-consuming minerals; mapping the distribution of swelling, sliming, and heap-blinding clays; and pinpointing problem areas on heap leach pad surfaces.

Feb 10, 2021

By J. C. Haptonstall

The Bismark Mine is located in northern Chihuahua, 150 km southwest of Ciudad Juarez. The ore deposit was discovered in 1979, and was placed in production in 1992. The production rate is about 2400 tpd from an ore reserve of 8.5M tonnes. Grades average about 8 % Zn, 0.5 % Pb, 0.2 % Cu and 50 g Ag per tonne. Substantial inflows of water into the under-ground mine complicate the operation. Complex metallurgy poses another challenge for the operators. Bismark was operated through a joint venture, Minera Bismark, S.A. de C.V., with U.S. and Mexican partners, but since early 1993, it is wholly Mexican-owned and operated.

Jan 1, 1994

By Steve Kral

Through advanced technology and innovative thinking, the mining industry has become one of the world’s leading industries in environmental protection. But it only takes one Summitville, Omai or, most recently, the Aurul gold tailings retreatment operation in Romania to provide ammunition to the industry’s critics in their attempts to sway public opinion against mining. So for the mining industry to continue operating with the public’s support, it must continue to improve its tailings waste-disposal processes and the dams that hold this waste. In January, about 120 specialists in the mine waste management field gathered together to discuss the available technologies and materials for controlling mine waste and mill tailings disposal. “Tailings and Mine Waste’00” was held at Colorado State University in Fort Collins, CO. This meeting, begun in 1978, is a continuing symposium. It provides a forum for environmental professionals to discuss the state-of-the-art in mill tailings and mine-waste disposal methods.

Jan 1, 2000

By Samir Kumar Pal, Rajasekar Rathanasamy, Gobinath Velu Kaliyannan, Moganapriya Chinnasamy, Sathish Kumar Palaniappan

The research examines the performance of uncoated and coated tungsten carbide-cobalt rock cutting bits. It aims to optimize process variables (cutting speed, depth, coating material) considering multiple output responses (cutting forces, specific energy, wear rate, material removed, angle of reaction forces). The study uses a hybrid optimization technique combining Taguchi design, grey relational analysis, and fuzzy logic. The optimal parameter combination was found to be cutting speed: 200 mm/s, cutting depth: 6 mm, and titanium aluminum silicon nitride coating.

Apr 24, 2022

By J. F. T. Agapito, L. J. Gilbride, K. Hollberg

Room-and-pillar mining at the Big Island Mine uses narrow, yield (i.e., load transferring) pillars to achieve high resource recovery and productivity. Two flat-lying 3- to 3fi-meter (10- to 11fi-ft) seams are mined. The interburden between the seams is about 10 meters (33 ft) and the cover depth is 250 to 330 meters (820 to 1,080 ft).Most of the mining has been single-seam, but two-seam mining will begin in the near future. Yield pillars minimize stress transfer between the seams. However, it is important that good long-term stability be maintained to prevent subsidence over a large portion of the mine beneath the Green River channel. Three stress issues impacting stability are discussed in this paper: (1) higher-than-gravity vertical pre-mining stresses, (2) time-dependent stress transfer or arching, and (3) stresses induced by strata gas. Although the stress environment and behavior is not fully understood, steps have been taken in mine design and operations to minimize impacts to stability. Stress determinations have been very important to verify analytical predictions used in mine design and in long-term stability assessment.

Jan 1, 2004

By Mingju Liu

The coal and gas outburst accident on May 20, 2007 at Sihe Coal Mine is unique in that there was no or very little soft coal in the coal seam and that the coal strength was very high. The outburst also showed that there was a very high gas content of 20-30 m3/t in the coal seam nearby the outburst site. Based on the field test and observations, together with laboratory experiments, detailed analysis was conducted on the controlling factors of coal and gas outburst potential at Sihe Coal Mine. Stress data available from Sihe Coal Mine, northern China, and other parts of the world, were also taken into account to facilitate the analysis. The results shows that the stress level was not abnormal compared to other coal fields in China prone to outbursts, and that gas contained in the coal seam was the main factor that triggered the outburst. All these factors were essentially controlled by the tectonic evolution features in Qinshui Coal Basin, to the Southeast of which Sihe coal field is located. Based on the analysis, assessment of coal seam outburst potential was carried out by measurements of coal seam gas contents, observation, and detection of soft coal layers in the coal seam. The results show that outbursts are limited to only a small part of the whole coal seam and that the eastern part of coal field is not prone to outbursts.

Jan 1, 2009

By Arun Kumar Singh

Wide variation in the nature of the coal seams and the surrounding rock mass of the Indian coalfields and very little information about the associated stress fields were observed to be the major hurdles in the straight forward application of a continuous miner (CM) based mechanised depillaring approach. Due to various techno-economic reasons, a considerably large number of coal seams have been developed and are standing on pillars in India. The development of pillars is done as per Indian coal mines regulation, which results in pillars of relatively large size. In fact, the large size of the pillars provides stiff natural support to control caving of the massive overlying strata. However, the size of these pillars is not conducive for the single pass pillar stripping technique and, therefore, there is a need for pillar splitting before pillar extraction/retreating. Splitting of the pillar may reduce the competency/stiffness of the pillar, which creates a chance of overriding during final extraction below a massive roof stratum. This paper first discusses the existing coal mining scenario in India followed by a brief presentation of geo-technical details of pillar extraction at the three sites where a CM has been introduced for depillaring/pillar retreating in the country to date. Based on past rock mechanics experiences with conventional depillaring faces, stability issues of the pillars, fenders, and stumps in and around the depillaring face are discussed. This may prove to be an important factor in the success of future CM faces. It is recognized that the application of the modern strata movement monitoring techniques may improve operation safety by providing valuable qualitative and quantitative information that can be used to improve the design of modern concepts like roof bolt based breaker line support during pillaring.

Jan 1, 2009

By Henry J. Schwellenbach

The New York Trap Rock Corporation has four plants located along the Hudson River, all within 70 miles of New York City. The company produces crushed stone for use as construction aggregate, with a total annual production amounting to 6 million tons. The crushed stone is moved to markets in metropolitan New York, New Jersey and Long island areas by water transportation. There are daily deliveries of approximately 35 scowloads to the market area. Its customers are contractors with ready-mixed concrete and asphalt plants located on the water, where the aggregate is unloaded for its ultimate use. For a number of years capital equipment was replaced only when the current operating machinery was no longer serviceable, or when' a need was apparent for a different type of equipment. There was no particular regard for efficiency or for operating and maintenance costs. Such lack of system often resulted in the emergency purchase of equipment which was later found to be unsuitable for the job. A few years ago it became apparent that a systematic procedure was necessary. After evaluation of several systems, an individualized plan was evolved from the basic pattern developed by the Machinery and Allied Products Institute. The system adopted by New York Trap Rock has proved wholly satisfactory.

Jan 1, 1959

A new analytical approach for characterizing and improving the performance of ball milling is presented. Individual ball mill circuit design and operating variables can be related to overall circuit performance through two distinct parameters for classification and breakage. The ball mill circuit functional performance equation is presented. Applications in the industrial plant and in the research field are discussed.

Jan 1, 1990

By H. W. Breathitt

World demand for phosphate rock has increased significantly in the past fifteen years. Prior to the early 1960's, most of the world production was obtained from Florida, North Africa, and Kola. As the 1960's arrived, new mines in North Florida and Eastern North Carolina, as well as expanded production in the Western United States, .increased domestic production. Many new mines overseas have also become significant. This includes countries such as Senegal, Togo, Israel, Spanish Sahara, and Jordan. Limited production, often as by-products, has been noted in South Africa, Brazil, and other countries. In recent years, and even recent months, we have learned of many new areas being considered as potential sources of phosphate rock. This includes Australia, Saudi Arabia, Mexico, Colombia, and Brazil. Many other developing countries have discoveries and are considering their new deposits, often with difficult beneficiation problems, as potential sources of phosphate. These factors all relate to expanded world, population and the demand for more fertilizer products to produce food. In this paper, four areas of the world with different types of phosphate deposits are briefly reviewed to contrast the ore beneficiation problems to Florida procedures--long considered the "standard" of the industry, at least for most of the United States' domestic production. Agrico has three large operating mines in Florida with total production capacity exceeding seven million tons per year. Here, pebble phosphate (+14 mesh material) is produced without the use of flotation, whereas all of the material finer than 14 mesh is subjected to flotation beneficiation to upgrade into high grade concentrates.

Jan 1, 1977

By C. Y. Haas

Of all the industrial clay minerals, attapulgite probably enjoys the widest variety of applications. A review published over three years ago by Haden and Schwint (18) cited some 80 individual uses, a list which continues to grow. In its near half-century of commercial life, attapulgite has received a generous share of research study and patent development effort, both on the part of producers as well as consumers. This work has been divided between understanding the mineral's structure or properties and applying it to specific end-uses. Naturally, information gained from the former has pointed toward opportunities in the latter. References of particular significance are cited throughout the text. Attapulgite's variety of uses derives from the unique three-dimensional structure and needle-shaped particle form of this crystalline hydrated magnesium aluminum silicate. Its inherent colloidal and sorptive properties are well known, and distinguish it from its sister clay minerals. Attapulgite is characterized by its high surface area, porosity, sorptivity, and decolorizing power. Its slips or slurries are viscous and thixotropic, however, unlike bentonite are not flocculated by electrolytes. In Table I are compared the general properties of attapulgite, bentonite, and kaolin. The properties in Table I are documented in greater detail by the wealth of scientific literature which has been published on the composition (14)(15), structure (6)(16), surface (16)(4)(22)(24), adsorption (31)(4)(5)(25), rheology (10-11)(12)(13)(26)(27)(32), plasticity (30) (31), and chemistry (23)(3)(7) of attapulgite. Attapulgite is the principal mineral constituent (70 to 80%) of attapulgite clay as it is commercially produced in the Georgia-Florida area of the United States. As mined, this clay also contains 10 to 1S% montmorillonite, sepiolite, and other clays; 4 to 8% quartz, and 1 to 5% calcite or dolomite. (18) During processing, non-clay fractions are removed so that commercial products are enriched to 85 to 90% attapulgite. By wet processing (such as practiced in the

Jan 1, 1971

By ANGELA NAIR AVELAR, Reiner Neumann, PAULO R. G. BRANDÃO

Three types of apatite were identified by means of cathodoluminescence (CL) images in flotation concentrate and tailing samples from the Catalão Mine in Brazil. They are predominantly blue apatite, followed by green apatite and, less frequently, yellow apatite. The chemical compositions of these types of apatite were determined by electron microprobe analysis and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Blue and green apatite responded well to the process, thus remaining in the concentrate, while yellow apatite remained in the tailings. Yellow apatite has the lowest phosphorus pentoxide (P2O5 ) content and largest anionic and cationic sites substitution, followed by green apatite, whereas blue apatite is the most homogeneous, with highest phosphorus (P) and calcium (Ca) grades and lowest substitution level.

By M. William Lallman

Potash production from natural brines of the Bonneville Salt Flats has a comparatively long history dating back to the start of World War I. However, it vas sot until the late 1930's that a successful commercial potash operation was achieved by a firm known as Bonneville Ltd. While improvements in operating techniques, pond design and equipment have been incorporated as they became available it should he understood that the basic technology developed in the late 30's and early 1940's by Bonneville Ltd, for potash production has not been changed significantly. The purpose of this paper is to present a brief review of the history, geology and hydrology of the Bonneville Potash operations and discuss the cur¬rent methods employed for brine collection, solar evaporation and the recovery of potash and other brine chemicals. A detailed study of the hydrogeology of the Bonneville Salt Flats wan made by L. J. Turk,1 Ph.D. thesis for Stanford University in 1969, under the auspices, of Kaiser Chemicals the Industrial Chemicals Division of Kaiser Aluminum & Chemical Corporation. Turk's thesis furnished much of the information presented in this paper.

Jan 1, 1976