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By G. Bulut, Ü. Yenial

"The use of recycled water in flotation has significant effects on flotation and selectivity because the recycled water contains many dissolved compounds and ions that alter the chemistry of the system. In this study, the effects of calcium, magnesium and sulfate, which are abundant components in recycled water, were investigated on galena, sphalerite and pyrite flotation using pure minerals and a complex sulfide ore by conducting bench-scale flotation, microflotation and zeta potential measurements. The bench-scale flotation tests indicated that higher recoveries of galena and sphalerite are obtained when water is recycled, due to higher concentrations of ions in recycled water. However, there was a critical ion concentration for galena recovery. The microflotation tests showed that galena recoveries at different pHs in recycled water are lower than in tap and distilled water. Pure sphalerite recoveries improved in recycled water in the bench-scale test with ore. Pure pyrite was depressed with recycled water as well. Zeta potentials became less negative with increased calcium and magnesium ion concentrations due to their adsorptions, and the presence of sulfate ions was seen to increase the negative charges of sphalerite and pyrite, conversely for galena. IntroductionWater is among the most important elements for mining and mineral processing. The distance to water sources is one of the major factors for mine site selection. The mining and mineral processing sector needs and consumes large quantities of water. In Chile in 2014, the copper mining sector alone consumed 12.7 m3/s fresh water for 1.189 tons of ore processing, and recycled 74 percent of the consumed water (Chilean Copper Commission, 2015). A plant that does not reuse or recycle any water will require 1.9 to 3.0 m3 of water per ton of ore processed (Gunson et al., 2012). Many stages of mineral processing, such as grinding, gravity concentration, dense medium separation, wet magnetic separation, flotation and hydrometallurgical operations, use large volumes of water (Schumann, Levay and Ametov, 2009).In mineral processing plants, the process water is recycled from the tailings dams, thickener overflows, and dewatering and filtration units. Wet concentration processes can require large quantities of water. Flotation, the most common process, typically takes place at 25 to 35 percent solids by mass. Most flotation plants practice at least some water reuse and recycled. Modern mines and mineral processing operations generally aim for zero water release (Levay, Smart and Skinner, 2001). In most cases, water quality has been found to affect flotation performance, and this interaction remains under investigation."

Jan 1, 2016

By P. J. Miranda, C. G. Anderson, L. G. Twidwell

Titanium is a metal of increasing worldwide strategic importance. The Center for Advanced Mineral and Metallurgical Processing (CAMP) at Montana Tech of the University of Montana is currently directing two titanium research initiatives. The first program, Titanium Extraction Mining and Process Engineering Initiative (TEMPER), is focused on producing low cost titanium through the identification and development of new mining, beneficiation and extraction technologies which will significantly reduce the cost of titanium production. This will directly benefit worldwide commercial applications. Secondly, CAMP is evaluating new technologies for fabrication of titanium utilizing the Free Form Titanium Fabrication (FFTF) initiative. These technologies may drastically reduce the cost and time to manufacture titanium components. Because of the high strength to weight ratio of titanium coupled with its superior corrosion characteristics, these programs will be of vital importance to expanding the commercial and strategic applications of titanium. An overview of these two new titanium initiatives will be presented in this paper.

Jan 1, 2005

By Kazumasa Taguchi

At the Kakogawa works of Kobe Steel. Ltd., the agglomeration facilities are composed of a pelletizing plant and sintering plant. This aim is to utilize raw materials efficiently and stabilize the raw material resources. Therefore at Kakogawa works, the blast furnaces (BF) have been operated with high pellet ratio and various developments for pellet properties have been achieved to improve the blast furnace performance. These developments include dolomite-fluxed pellets, new-porous pellets and crushed pellets. As a results of these improvements, pellets have achieved almost the same performance as sinter at high temperature regarding properties such as the softening, melting and reduction behaviour. However, some problems on shape have remained to be solved. Spherical pellets flow easily into the center of the furnace and form mixed layers of pellets and cokes. Therefore, in BF operations with these pellets it becomes more difficult to keep proper and stable gas distribution.

Jan 1, 1983

By Yu. P. Astafyev

The, control of drilling and blasting is a complicated dynamic system whose aim is to ensure safety and prepare rock of required grade and the standard level of broken material reserves Unlike other processes drilling and blasting, as an object have the following features: -a large variety of drilling and blasting methods due to specific conditions of blasting, various types of drilling equipment, schemes-of blasting, types of explosives and others; -relative continuity of drilling, the character of mammoth blasts being discrete; -increased requirements to the safety of blasting;; -a great. number of control parameters, some of them having a qualitative characteristic but not a quantitative one; -availability of feedforward and feedback with other mining processes in terms of time and space. These features predetermine the hierarchical structure of an automated system of planning and control of drilling and blasting (fig.1). The system is implemented on the basis of unity of the data base and in interre lation with other problems of controlling mining operations. An automated system of this kind makes it possible to take optimal decisions actually on all the levels and stages of operations, with rock having been blasted before extraction.

Jan 1, 1986

By D. D. Lei, H. Sevim

In a recently developed, long-term open pit production planning model, the optimal plan is found by exhaustively searching through nested pits of maximum metal contents. A more efficient, dynamic programming (DP) based search algorithm now replaces the exhaustive search algorithm that requires prohibitively long execution time in real life cases. The logic and formulation of the newly developed search algorithm are illustrated through a small hypothetical case. An actual gold deposit is treated to demonstrate that the algorithm does indeed find the optimal production plan among all possible plans. A comparison, in terms of computational savings between the two algorithms, is also given.

Jan 1, 1995

By Cyrus W. Field

Metalliferous sediments constitute an important component of the sedimentary veneer that overlies basaltic oceanic crust of the Nazca Plate and elsewhere. Although first collected more than one century ago near the East Pacific Rise during the Challenger Expedition and recognized for their anomalously high content of Fe and Mn, occurring as very fine-grained, yellow-orange, oxides, hydroxides, and oxyhydroxides, it was not until the more detailed studies of Bostrom and Peterson (1966) that their geologic significance and concentrations of other transition metals were fully appreciated. The Nazca Plate is a dynamic lithospheric unit bordered by the Peru-Chile trench and the East Pacific Rise to the east and west, and by the Galapagos Rift and the Chile Rise to the north and south (Fig. 1). Samples employed in this study were taken from piston core recovered from the Nazca Plate (Fig. 2), D. S. D. P. drill core from the northeast Pacific (Dymond and others, 1973), ferromanganese nodules from dredge-haul s at several locations, and from hydrothermal mineral deposits of the Andes. Our efforts have been largely sponsored by the National Science Foundation through its International Decade of Ocean Exploration Pro- gram. The metalliferous fraction of these sediments is widespread, but generally small. Sedimentation is dominated by biogenic silica in the equatorial latitudes, terrigenous debris adjacent to the South American Continent, and by biogenic carbonate elsewhere, except at depths below 3500 m in the central and northwest parts of the Nazca Plate near the East Pacific Rise. Contributions of these distinctive sediment types are shown by the distributions of Si02, A1203, and CaC03 given in Figure 3.

Jan 1, 1982

By Saurabh Rastogi, Vikram Shishodia, B. Pitchumani

Comminution is a unit operation which consumes major part of energy in mineral processing industries such as fertilizer production. Ball mills are widely used for size reduction of a given ore to the liberation size that is required in further beneficiation processes. In grinding of materials much effort is concentrated on control of top size of the product and this results in production of fines, also creates secondary problems of pollution due to the difficulty in the collection of fine particles. The present work has been carried out to control product size distribution for rock phosphate grinding in an Industrial Ball Mill of 600 TPD. The plant data are taken for a given feed distribution and mill operating conditions. The information at various Ball Size distributions are collected. The comminution functions such as specific rate of breakage and breakage distribution functions are estimated by back calculation technique to solve the mass balance equation. A simulation program is written to study the product size distribution obtained for various ball size distribution.

Jan 1, 1993

By H. Janas

In a gas/coal outburst the gas plays an active, driving part. The proneness of coal to outbursts can be determined by means of its gas emission properties, since coal that is liable to outbursts differs from coal with normal gas emission properties in that it liberates its gas from the sorptive bond more quickly. There is a risk of outburst when the flow of metha¬ne originally desorbed by the coal is sufficient to move the loosened coal which has been broken suddenly. The violence of a gas/coal outburst can be evaluated from the distance of projection of the mass of coal. It depends on the gas pressure and on the liability to outburst of the coal at the original centre of the outburst. Both factors are complementary in their effects so that the same work is done in a gas/coal outburst when there is a high gas pressure and low proneness to outburst as when there is a low gas pressure and a higher proneness to outburst. The gas pressure in the coal increases with its gas content. Consequently it is possible to deduce the gas pressure of a coal seam from its gas content. In the Federal Republic of Germany the risk of a gas/coal outburst is thought to exist when the desorbable gas content of the coal reaches or exceeds the value of 9 m3/ton and if the specific limit value of the proneness to outburst is exeeded. The Mine Ventilation Testing Station of the Westfalische Berggewerkschaftskasse has developed a new method for determining the risk of gas outbursts immediately after taking the samples at the coal face (1), (2).

Jan 1, 1980

By Felicia F. Peng

One of the serious environmental problems related with the extraction of coal for carbon and energy resources is that upon preparation of coal a large quantity of fine coal has been discarded and/or lost to tailing impoundments. These problems present hazardous conditions to the local community. Also, the precious heating value of energy resources has been wasted and Left unrecovered in the tailing impoundments. Both RCR and SMRC ACTs recognize and mandate an investigation into slurry impoundment problems, including consideration of potential use of those coal fines in the tailing ponds. Bituminous coal producing district 46 encompasses the northern panhandle of West Virginia. The major producing seam in this district is the Pittsburgh coal, 1-7 meters thick. 75 percent of the coal producted in this district is deep mine. This district produces approximately 3 million tons of coal waste materials annually. One of the coal preparation plants in the district which we have visited has been processing Pittsburgh too. 8 seam coal for the past ten years. The characteristic data of the Pittsburgh raw coal is shown in Table 1. The raw coal produced in this district is characterized by its high heating value, high ash and high sulfur contents. The coal preparation plant flowsheet designed and used to process this Pittsburgh raw coal prior to 1979 is shown in Figure 1. It was a partial coal cleaning plant' with 1 092 mt/hr designed capacity, which consisted mainly of a coarse coal cleaning circuit. The rejected fine particles in the size range of -600µm which consisted of vorsiv underflow and cyclone underflow from clean coal streams and spiral classifier overflow from refuse stream were settled down in a thickener with the aid of anionic flocculant prior to being pumped to the tailing ponds for disposal. Figure 2 shows that the same coal preparation plant in Figure 1 was modified to a semi-complete coal cleaning plant and expanded its designed capacity to 1 820 mt/hr, when market of coal fines becomes feasible in 1979. Tabling in the clean coal circuit and thermal dryer in the dewatering circuit were added to the flow sheet. The purpose is to recover more coal fines, reduce more pyritic sulfur and ash contents in coal and also to reduce solid waste material to be stored into the slurry impoundment, giving them a Longer Life. The rejected fine particles fed to the thickener are clean coal fines from two cyclone overflows and the fine refuse from the rufuse cyclone overflow. The clean coal fines presently lost to the tailing impoundments are in the size range of -150 µm and constitute about 5 percent of the overall plant feed. Total amount of tailing waste material accumulated in a tailing impoundment is estimated at 1.3 million metricton for the past ten years.

Jan 1, 1982

By W. Trask

The state of the art in crawler transporters for loads to 3 kt (3300 st) is sufficiently advanced to allow compilation of job cost figures showing the economics of tracked vehicle use under a wide variety of circumstances. Initial costs, cost per ton of capacity, and operational and maintenance expenses are presented. Data is derived from participation by the Neil F. Lampson Co. in more than 3 Mt - km (2.05 million st - mile) of crawler operation during the past 16 years. The effects of economics on future design trends will be examined with particular reference to versatility, portability, and capacity.

Jan 1, 1987

By R. Mittler

Over 100 saprolite samples from Turkey Hill Gold Mine, Lumpkin County, Georgia, were analyzed (-80 mesh) for As, Au, and Sb. Maximum values are 16.2 ppm As, 7.9 ppm Au, and 29.1 ppm Sb. Results show trace element content of saprolite varies with topography: ridge top samples show a pronounced decrease in Au and Sb, and to a lesser degree in As, whereas, slope and valley samples have anomalous Au and Sb concentrations, with no discernable pattern for As. Statistical analysis shows strong correlation between Au and Sb and none between Au and As. This study will serve as a model for gold exploration in deeply weathered terrains with variable relief.

Jan 1, 1987

By S. K. Singh

To meet increasing demand of coal, underground mining is largely being replaced by the exploitation at deeper horizons and with greater complexities. The exploitation-proposition may be below not-to-be-disturbed surface properties or below water-bodies, posing a constant threat of inundation. Also, the mounting pressures to limit the adverse impacts on the environment bring the extraction-undertaking to face more challenges. An understanding of subsidence-mechanism and a rational quantification of subsidence parameters is a requisite herein. This paper presents such pragmatic quantification, validated at mine-sites in India. In comparison, better productivity, conservation and safety is ensured in this approach.

Jan 1, 1999

By R. Buisman, K. Reyneke, M. Fullam, J. V. Brown

Most mineral processes currently in use, such as flotation, spirals, gravity concentrators, etc., are only effective over a small range of sizes, hence the upstream need for technology to accurately classify fines by size. The Pansep’s design is revolutionary. Slurry is fed onto connected mesh sections that move without bending or vibration, in a circular motion. Both sides of the screen mesh are utilized, so Panseps are self-cleaning and has half the footprint of other mesh-type screens. Developed in South Africa in 1997, the Pansep has proved itself very effective as a wet fines screen to effectively classify fine mineral fractions from 50 to 2,000 micron (325 to 10 mesh).

Jan 1, 2001

By E. E. Jones

The lignites of Arkansas, Louisiana and Texas are typically described as muitiseam deposits which contain quantities of day and sand in thin lenses or in admixture with the fuel itself. These materials are often included in the run-of-mine fuel and can have very adverse effects in the end use. Since May of 1982 the Dow Chemical Co. has operated a pilot plant for the beneficiation of lignites. This facility has successfully removed sand, clays and petrified wood from the lignite producing a fuel comparable to or better than the selectively harvested run-of-mine materials. The design, operation and results from this plant were presented by J. H. Everitt at the 1984 Coal Technology Conference.

Jan 1, 1986

By G. T. Adel, P. E. Richardson, R. Pazhianur

Cathodic protection using impressed current was employed to reduce mill wall wear during ball milling. Wear rates were determined from weight-loss measurements made on four 1-in.-diam mild steel coupons that were installed flush with the interior surface of the mill wall. Grinding tests were conducted on quartz, pyrite and quartz-pyrite mixtures at pH levels of 4.6, 7.1 and 9.2. Cathodic protection was shown to reduce mill wear by 30% to 60%. An examination of the coupon surfaces using scanning electron microscopy showed that cathodic protection greatly reduced pitting corrosion. The presence of a sulfide mineral, such as pyrite, was found to increase the wear rate significantly, possibly due to galvanic interactions. It was also found that the wear rate is significantly higher than the sum of abrasive wear and the corrosive wear, due to a synergistic effect.

Jan 1, 1998

By Greg Hodges

Sand-and-gravel aggregates have become the number-one, nonmetallic-mineral resource in the world. Surficial aggregate deposits of economic size are becoming increasingly rare in most parts of Canada. In southern Saskatchewan, this is especially true, and detection and delineation of intertill sand-and-gravel deposits with airborne electromagnetic (EM) surveys have proven very successful. Airborne and ground geophysical surveys detect such deposits by their resistivity contrast relative to the surrounding clay-rich soils. Dighem helicopter-borne electromagnetic surveys map soil variations over a large area quickly and cost effectively, greatly reducing the cost of detecting and mapping deposits compared with traditional methods (air-photo interpretation, ground EM, and drilling.). The multiple-frequency EM system used by Dighem can map variations both horizontally and vertically. Magnetic data collected simultaneously are useful in mapping bedrock geology. Both resistivity and bedrock maps aid in the important task of reducing drilling costs and person-hours in the field. The results of the survey are presented as maps of ground resistivity, which are relatively easy to interpret. These maps are produced in the field at the time of the survey, making quick follow-up of the survey possible. Airborne EM surveys can map the extent and depth of aggregate deposits more effectively than is practical from the ground. Since aggregate deposits can vary tremendously in a very short distance (<300 m) large-area EM maps can show both local area variability and also help develop intertill trends. A test survey for the Saskatchewan Highways and Transportation Department over a 3-km by 5-km area mapped all the known deposits as well as some unknown deposits, subsequently proven by drilling. The test-survey data show that the method not only detected the deposits, but also gave an estimate of the shape (volume) of each of the deposits. Comparison of the data to drill sections shows excellent correlation. Theoretical modelling demonstrates that the multifrequency system can discriminate sand and gravel from bedrock ridges. Since the successful test work, about 725 km2 of ground have been surveyed, resulting in the discovery of four new deposits, which can be used immediately, resulting in significant savings for the Saskatchewan government and taxpayer.

Jan 1, 1999

By J. Pinkley

In June of 2002 Hilti North America received the first MSHA permissible approval for usage of a powder actuated tool device in a gassy mine atmosphere. The purpose of this paper is to discuss the implementation of this commonly utilized tool technology in the construction industry, to the underground gassy mining industry over the course of the last 5 years. Prior to June of 2002, underground gassy mining industry had attached materials such as ventilation curtains, power cables, communication cables, signage, and other materials by either manually driving individual spads or nails into the mine roof or rib or by attachment to existing roof bolt bearing plates. The Hilti DX 460 powder actuated tool is portable, durable, and lightweight (4.5 pounds). The Hilti DX 460 powder actuated tool system is powered by Hilti .27 caliber permissible explosive boosters. The energy force of the Hilti .27 booster?s acts on a captive piston principle in the Hilti DX 460 powder actuated tool, that applies the setting force for the direct fastening to the individual fastener chosen for the application by the end user. Each year Hilti can be called upon by MSHA to provide booster materials for re-testing per our Hilti DX PAD 1/00 approval.

Jan 1, 2008

By Nasri Munfah

Long Island Rail Road’s (LIRR) service to New York City is limited to Penn Station on the West Side of Manhattan, which is operating at its practical capacity for the commuter railroad. This situation imposes serious considerations for future growth and limits the destination of many Long Island commuters. The East Side Access Project will provide a connection of the LIRR to the landmark Grand Central Terminal (GCT)on the East Side of Manhattan. The construction of the connection will require significant tunneling and underground work utilizing a variety of construction techniques. In Queens, the connection will require five soft ground tunnels using pressurized face tunnel boring machine. In Manhattan, the connection will require a series of rock tunnels and caverns connecting to two deep large station caverns under GCT to accommodate eight tracks with four platforms in a stacked configuration. The caverns housing train rooms are connected to the lower level of GCT where a large concourse will be provided. With a budget of $4.3 Billion, The East Side Access Project is the largest transportation project ever undertaken in New York City. This paper provides an overview of the project, discusses its environmental and the engineering challenges, and provides an insight into the design development to date.

Jan 1, 2001

By David J. Leeds

Increased interest in the utilization of the underground environment for water conveyance tunnels, vehicular tunnels, room and pillar type storage chambers, and military installations has focused attention on the possible effects of seismic activity on the stability of these types of structures. Earthquake experience has generally been related to the seismic stability on the surface of the earth. To establish aseismic design criteria, we attempt to predict the seismic exposure of a given site, both in terms of the spectrum of motion to which the structure must react favorably, and the recurrence rate of that motion. Experience gained from studying the effects of the Plowshare underground nuclear tests on existing tunnels and mines, coupled with the experience of the behavior of tunnels and mines in earthquake regions, provides us with an insight to predict the possible effects of earthquakes on underground openings and to establish design criteria. The type of damage ranges from minor fracturing and movements along pre-existing joints or faults through deformation of openings to collapse. The methods used to establish the seismic design criteria for an underground opening require modification of surface criteria to account for the difference in both amplitude and spectra underground. An aseismic evaluation should be performed on all important projects in areas exposed to possible earthquake motion. To perform this evaluation, information is required pertaining to the geometry and properties of structure and ground. Dynamic as well as static properties are required. A prediction of performance can be derived by exposing a model of the site, expressed in terms of its properties and geometry, to a design earthquake.

Jan 1, 1997

By Claus Becker

The Mixshield is a tunnelling machine for water bearing soft soils. Developed on the basis of the Hydroshield, it extents the application of this machine to cohesive soils. The design of the drum-type machine allows three different applications 1. As shield with liquid supported face and hydraulical mucking 2. As Compressed-Air-Shield 3. As Earth pressure balanced shield. The Mixshield is employed on three big contracts 1. a 6.3 km ring tunnel in Hamburg, outer diameter 5.95 m, with a new developed segmented concrete lining 2. a 1.9 km pipe-jack job near Cologne, o.d. 3.6 m 3. Metro Lot 3 in Lille/France, o.d. 7.7 m, 3.2 km long with segmented concrete lining and a most sophisticated separation-plant The site experiences will be reported.

Jan 1, 1987