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By B. Simser, T. Butler, A. Hall

The longterm future of Glencores’ mining operations in the Sudbury basin area of Ontario, Canada likely depends on mining deposits at depths below two kilometres. To gain a better insight into the rockmass response to mining, a geological scouthole program has been implemented at Glencores’ Nickel Rim Deep and Onaping Depth Project to gain insight into rockmass conditions ahead of the devel-opment face. The scouthole program involves drilling long (up to 600 m) subhorizontal boreholes drilled ahead of the development end and collecting data about the rockmass conditions from various geophysi-cal and mechanical tools (in addition to conventional core logging). Once all data has been collected and the borehole is available, seismic sensors are installed up to 450 m down the hole as part of the micro-seismic monitoring program with the leading sensor always located ahead of the development end. The recorded seismic data is used to provide realtime insight into the rockmass response to mining. On May 20, 2017 a flurry of seismicity with a maximum moment magnitude (Mw) of 0.7 occurred causing damage to the ramp heading. Data from the microseismic monitoring system had indicated that conditions at the development end were changing prior to the rockburst. A back analysis of the scouthole data indicated a clear anomaly in the rockmass at the location of the rockburst. The scouthole data also provided sufficient information to suggest that once this anomalous zone was exited, mining conditions would improve. With the microseismic monitoring system providing realtime information from the rockmass, the area was re-habilitated and ramp development continued successfully. Details of the rehabilitation and adjustments to the ramp development are discussed. Some correlations between the scouthole data and recorded micro-seismicity are also presented.

Apr 26, 2022

By F. Arslan

Gold extraction from refractory ores is still a problem. Gold losses in the cyanidation process are mainly due to the presence of sulfides and carbonaceous materials. Oxidation of carbon and sulfide minerals by sodium hypochlorite is a possible method to render the ore amenable to cyanidation, and earlier work by the USBM indicates that electrochemical generation of hypochlorite is promising. Laboratory work was carried out on the oxidation of pyrite and carbon in an electrochemical cell with a sodium chloride electrolyte. The results of preliminary tests are discussed in relation to the mechanism of electrooxidation of refractory gold ores and the estimation of current efficiency.

Jan 1, 1991

By James M. Stauffer

There are many types of filters designed to separate a solid from a liquid, including plate and frame presses, pressure leaf filters, gravity filters and vacuum filters. This discussion will be limited to continuous vacuum filtration and, specifically, to continuous rotary vacuum disc filters, drum filters and horizontal belt filters. The use of vacuum filtration can be advantageous in that: 1. The feed slurry can be delivered to the filter either by gravity or by a simple, inexpensive low pressure pump that only has to overcome the resistance of the feed piping system. 2. The filter equipment does not have to withstand high pressures. Consequently, a wide range of materials of construction, including plastic and fiberglas reinforced polyester (FRP), can be used in the fabrication. 3. After the form time, the filter cake is exposed to the atmosphere and the cake is accessible for further operations such as mechanical or physical dewatering, washing, and sampling on a continuous basis. 4. The discharge of the dewatered solids is continuous for directly feeding to the next operation; for example, a dryer. 5. Various methods of discharge can be fitted to the filter to effect optimum discharge of the dewatered cake solids. The principal of operation of a vacuum filter, regardless of type, is basically the same. The filter incorporates a filter medium supported on a drainage system and arranged so that the mixture to be separated (feed slurry) can be introduced to one side of the filter medium on which the solids are trapped and through which the liquid (filtrate) flows due to the applied vacuum.

Jan 1, 1979

By Robert C. Maxton

The foundry industry is a basic source of structural component for all industry. Millions of tons of castings are produced annually in both ferrous and nonferrous alloys. These castings are subjected to a wide variety of heat treatments, finishing techniques, mechanical tests and machining operations. Through all of these steps the quality of the casting is of paramount importance to the end use of the product. The Quality Assurance Program at Minneapolis Electric Steel Castings Company is designed and established to provide a superior product for both original equipment manufacturers and the mining industry.

Jan 1, 1982

By Otto Braach, Wolfgang Frietzsche, Erdogan Gürkan

The Westerschelde Tunnel is located in the south of the Netherlands and links the two parts of the Provinces of Zeeland, Zeeuws-Vlaanderen and Zuid-Beveland, which are separated by the Westerschelde. Road traf?c has up till now taken the detour via Belgium or crossed by ferry. This unsatisfactory transport link signifies major economic disadvantages above all for Zeeuws-Vlaanderen. The first fixed link for road traffic between the communities of Terneuzen and Borsele are to be created by means of the two 6.6 km long tunnel tubes down to 65 m below sea level.

Jan 1, 2003

By R. A. Seitz

This paper presents a framework for analyzing the theory and industrial practice of coal flotation and gives some examples of its use for understanding flotation phenomena and optimizing/controlling flotation circuit performance. It is based on extensive laboratory and in plant test work conducted over the past several years by researchers at MTU as well as an analysis of the literature. Previous researchers have usually considered either the surface chemistry or the kinetics of coal flotation behavior, only rarely have these factors been considered together. However, these factors must be considered together in order to gain a clear understanding of the theory underlying coal flotation such that its practical application can be optimized. Fortunately, this complex objective can be achieved by considering the recovery and rate of recovery of the different types of particles present in the feed to coal flotation circuits and the fundamental mechanisms responsible for these recovery phenomena. The influence of three major groups of variables must be considered: control variables (reagent additions, aeration rate, etc.); disturbance variables (feed pH, percent solids, etc.); and circuit design variables (number of cells, circuit arrangement, etc.). Each of these groups of variables affects process kinetics in a clearly understandable manner, which, once determined, is extremely useful in circuit design and optimization. This paper includes a discussion of the use of the proposed framework to explain the effects of some coal characteristics on flotation performance. In addition, an example of using this analysis to optimize the performance of a coal flotation circuit using frother and collector addition levels is included.

Jan 1, 1985

By R. L. Keiski, H. Miettunen

"The serpentinite massifs of Hitura are located in the municipality of Nivala in Central Finland. The most important sulfide minerals in the ore are pentlandite, pyrrhotite and chalcopyrite. The ore body consists of amphibolite rocks in contact with serpentinite against mica gneiss. The mean Ni grade of the ore is about 0.7%, and the highest Ni grades have been encountered in close contact. In general, the inner parts of the ore are strongly serpentinized ultramafite and some sulfides have been converted to mackinawite and valleriite. The degree of alteration varies considerably within the ore body and, correspondingly, the grain size of the sulfides varies as well. In this study, flotation tests were done with samples from different zones of the ore body. The flotation test results on the bench scale and plant scale are discussed in terms of the mineralogical features of the ore. Ores in the North Hitura zone differ from those in the South Hitura zone.IntroductionThe Hitura nickel mine, like the entire Nivala area, is part of the Bothnian Svecokarelian schist zone, where numerous Ni-Cu boulders have been discovered since the early 1930s. The Nivala area has therefore been the subject of exploration activities by the Geological Survey of Finland (GSF) and mining companies. The first period of exploration started in 1936, and the Makola nickel deposit, located 3 km south of the Hitura mine, was discovered by GSF in 1937. About 415,000 tonnes of ore were mined at Makola between 1941 and 1954. In 1937, during the exploration and development stage of the Makola mine, boulder tracing and a geophysical survey revealed a significant ultramafic body with some lowgrade Ni-Cu occurrences in the South Hitura zone.In 1961, GSF continued the exploration program in the area and discovered the North Hitura ultramafic complex and its allied Ni-Cu occurrences. In 1964, Outokumpu Oy bought the property and, after underground exploration, comprehensive mineralogical studies, process research and a feasibility study, production started in 1970 (Isohanni et al., 1985)."

Jan 1, 2015

By Emily Muto

LiDAR technology has made it possible to map large areas of underground mines accurately and rapidly in three dimensions. MSHA Technical Support began implementing LiDAR technology in conjunction with the Agency’s Pillar Collapse Initiative, using scans to determine width-to-height ratios (w/h) of pillars adjacent to mass collapse areas and to conduct risk assessments for global pillar stability in U.S. stone mines. This work quickly expanded to include change detection, such as measuring many pillars to show which are deteriorating over time. Change detection has also been used in ground falls and squeeze areas to see if they have continued to propagate. LiDAR technology supports accurate data acquisition of unstable mining conditions from safe distances. For example, once the LiDAR scan has been processed, it can measure roof fall cavity heights and volumes with the user at a stable ground location. Some LiDAR scanners can collect geologic data, such as joint orientations.

Jun 25, 2024

By Cem Şensöğüt, Özer Ören, Yaşar Kasap

The mining sector is one of the leading sectors where work accidents are most intense because of the constant change of work environment and heavy working conditions. The losses and the halt of production after the accident negatively affect productivity and production efficiency. It has been found that there are very few studies on the use of Data Envelopment Analysis (DEA), which is one of the nonparametric efficiency analysis methods, in the evaluation of mining sector occupational accidents. According to parametric activity measurement methods, it has been tried to show that the DEA can also offer the opportunity to interpret work accidents by taking advantage of its advantages. Due to the application of open-pit mining methods along with underground working techniques which increase the risk factors with respect to accidents at work that occurred between 2012 and 2018 of Western Lignite Corporation (WLC) were tried to be analyzed in the present work. As a result of the analytical work using Data Envelopment Analysis (DEA) for the years 2014, 2015, 2016, 2017, and 2018, inefficiency has been determined in both underground and surface operations. According to the results obtained, it was determined that WLC could not produce enough production in both the underground and surface coal mining operation, despite the accidents that occurred, while it had the opportunity to produce more. In addition, it was found that the increase in accidents occurred more than the increase in the amount of production during the years studied.

Jul 4, 2021

By J. L. Heaver

All complete plant foods require phosphorus, nitrogen and potassium. And phosphate rock is the primary source for the phosphorus of the inorganic fertilizers. As more and more world food production is grown with these chemical fertilizers and since the Florida field supplies over 30% of the phosphorus component, let us look at the vital phosphate industry. Mining of phosphate rock in Central Florida began in 1891 and production has continued to grow at a steady pace. In 1965 a phosphate mine was opened in Hamilton County, North Florida and one in Beaufort County, North Carolina in 1966 . Since the beginning of mining in 1891, approximately 700 million metric tons of phosphate rock have been produced of this amount one-half was mined in the last 11 years. While the field was not deliberately "high-graded," the best of the known deposits were mined first. Those now being mined, and those yet to be mined, cost more to operate and the product is of lower grade. The U. S. Bureau of Mines' data for 1977 lists "Florida" phosphate rock production as 40.6 million tons; 86% of U. S. production and 85% of "Florida" capacity. The U. S. Bureau of Mines includes North Carolina production in "Florida" statistics so as not to reveal individual data for the one mine operating there. Approximately one-half of "Florida" production is exported, either as rock or as rock equivalent in upgraded products. Deposits of phosphate rock necessary to support present and future production are catalogued as: reserves, paramarginal reserves and resources. Reserves denote deposits which can be mined at a profit now. Paramarginal reserves are defined by the U. S. Bureau of Mines and the U. S. Geological Survey as: that portion of sub-economic resources that a) borders on being capable of production economically, or b) is not commercially available solely because of legal or political circumstances. The " b)" part of this definition may now be expanded to include environmental controls and requirements. Resources are deposits which cannot be mined at a profit at present. Listed in Table I are reasonable values for each of the three categories of phosphate deposits in the northern and southern parts of Central Florida. North Florida and North Carolina.

Jan 1, 1978

By A. B. Cecala, G. W. Klinowski

Introduction The US Bureau of Mines has designed and evaluated total mill ventilation systems (TMVS) at two mineral-processing operations. Both systems have proven proficient at cost-effectively reducing respirable dust levels throughout the mills. An 11.8-m3/sec (25,000-cfm) system installed at a clay-processing mill provided about 10 air changes per hour (acph). This system reduced respirable dust concentrations by about 40% throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 23.6 and 47.2 m3/sec (50,000 and 100,000 cfm) of ventilation to the mill building, corresponding to 17 and 34 acph. Average millwide respirable dust reductions were 36% and 64%, respectively. This work was done to determine general guidelines and design criteria for operations that may be interested in implementing TMVS. TMVS should be designed to draw clean make-up air in near the base of the mill. This air provides general purging and may clear some dust-laden areas throughout the mill structure. It is discharged at or near the top of the structure. Without the TMVS, dust can exit the building through open doors, windows, etc. and contaminate outside plant workers. This dust can also be recirculated back into the mill building causing additional contamination problems. TMVS is not a stand-alone system. It is a supplemental technique to assist other localized dust control systems (Mody et al., 1987). Testing Total mill ventilation systems were evaluated at two processing operations. For both tests, the primary goal was to determine the reduction in respirable dust throughout the structure. Test site No. 1. The first evaluation was performed at a clay-crushing and screening mill in New York. The mill's base dimensions were 39.6 x 9.8 m (130 x 32 ft), giving a volumetric capacity of 4250 m3 (150,000 cu ft). The TMVS was designed to provide 12 m3/sec (25,430 cfm) of ventilation air to the mill, representing about 10 acph. This was accomplished by three 4 m3/sec (8475 cfm) roof-powered exhaustors that were evenly spaced across the roof. Three wall louvers provided inlets for make-up air at the mill's base. Two evaluations were performed at this mill. The first occurred for two days in December when outside air temperatures ranged from -12.2° to 4.4° C (10° to 40° F). Temperatures with the wind chill factor dropped as low as -34° to -40° C (-29 to -40° F) during the early morning. The second evaluation was in April when outside air temperatures ranged between 10° to 26.7° C (50° to 80° F). These two evaluations verified the effectiveness of TMVS in lowering respirable-dust concentrations throughout the mill. Gravimetric-sampler respirable-dust concentrations in December ranged from 0.22 to 2.39 mg/m3 under normal conditions, compared to 0.13 to 1.55 mg/m3 with TMVS. In April, respirable dust concentrations ranged from 0.29 to 4.84 mg/m3 under normal conditions compared to 0.21 to 2.37 mg/m3 with the system on. TMVS also increased visibility throughout the mill building. Dust reductions for gravimetric and RAM-I instruments are listed in Table 1. Each value was determined by comparing the average concentration for the entire day of testing for normal and TMVS values. The mean/standard deviation values for gravimetric and RAM-1 results were 42.5/17.6 and 37.1/16.8, respectively.

Jan 1, 1996

By B. L. Gibbs

The mining industry is constantly in a state of flux -boom or bust; mine openings and closings. Part of the reason is the nature of ore deposits -they are there or they are not. Once they are mined, they are reclaimed and the move is on to the next deposit. Risks are usually high, and payoffs can be great or not so great. Many factors go into making a property payoff, and mining companies are continually searching for ways to remain profitable as long as possible. Computers and the people who can make them work are one of the ways available to improve productivity and ensure this happens. Computers have been used in the mining industry for the last 30 years (and more in a few cases). During the past 10 years, the explosion of micro-computing has changed how many mining companies do their work.

Jan 1, 1993

By C. Flores, R. Y. Wan, M. C. Fuerstenau, T. S. Jordan

Most oxidized manganiferous silver ores contain manganese associated with silver and are not amenable to conventional silver extraction methods, including direct standard cyanidation techniques. However, it is known that dissolution of the manganese might yield a suitable material from which silver can be recovered by conventional methods. In the segregation process, which involves heating the ore with a small quantity of salt and with a source of reducing agent to 680°C - 800°C, the silver is volatilized, migrates and is reduced to metallic silver particles. Conventional cyanide leaching is applied to the resulting calcine. Laboratory investigations have been conducted on a manganiferous silver ore analyzing 0.02 % Cu, 0.09 % Pb, 0.33 % Zn, 12.55 % Mn and 187 g/ton Ag to study the influence of roasting temperature and time, quantity of salt and quantity of coke on silver extraction by the application of segregation roasting followed by cyanidation. Cyanide leaching tests were carried out at room temperature on the segregated calcines produced by using an alkaline cyanide solution containing 2.0 lb/ton of NaCN at pH 11 for 72 hours. The results indicated that 97.8 % of silver extraction can be attained at 850°C, with 2.0 % salt, 1.0 % Coke and 30 minutes of roasting time.

Jan 1, 1993

By William Gleason

There was a time, not too long ago, when the most daunting challenges facing those in the mining and mineral processing industries could be solved through better technologies and better practices. But now the challenges that come from the actual acts of mining and processing are just part of the bigger picture. SME?s Colorado Section of the Mineral Processing Division (MPD) hosted its 63rd annual meeting at the Broadmoor Hotel in Colorado Springs, April 25-27 and, while the conference had its fair share or mineralolgy and processing presentations that were heavy on the technical side of things, this year?s conference was also focused on the issues of permitting, regulation compliance and legislative issues. The so-called ?softer? issues, that, if not addressed, can lead to very real and very hard challenges. Under the theme ?Mine your own business - permits, startups, expansions and resources,? even the most dedicated metallurgists were drawn into the discussions of politics and legislation, and how those issues affect their business. Fittingly, Colorado Mining Association (CMA) president Stuart Sanderson was honored with the Arthur C. Daman Lifetime Achievement Award. Sanderson, an outspoken proponent for the mining industry in Colorado and beyond, also presented the keynote address to the lunch crowd where he spoke about framing public opinion toward mining and the efforts of the CMA to move the public opinion dial in a direction more favorable to mining. Sanderson explained that Colorado, once a Republican stronghold, turned after 2002 and now is controlled by Democrats who are traditionally less supportive of the mining industry. Sanderson said the deciding factor in the power shift was money, as supporters of Democrats outspent Republicans in the most recent election cycles. CMA has done its part to keep mining going in the state with a broad marketing campaign that was outlined by Sanderson.

Aug 1, 2013

By William X. Chavez

The Mantos Blancos copper-silver district is located in northern Chile about 45 kilometers northeast of Antofagasta, as shown in Figure 1. Disseminated and veinlet copper and copper-iron sulfides containing economically significant silver values are hosted by andesitic to rhyolitic volcanic rocks of probable Jurassic age (Chavez, 1983). Field, mineralogical, textural and lithochemical evidence show that three major alteration types may be recognized within the district: (1) district-wide sodium metasomatism, manifested as albitization of feldspars and development of albite veinlets and pore-fillings, (2) local to widespread, incipient to intense addition (chloritization) or removal (bleaching) of magnesium and iron and (3) local to widespread, moderate to intense hematitization, usually spatially associated with bornite-digenite-covellite (as specularite) or digenite-covellite-chalcocite (as red hematite staining with or without specularite) mineralization. Carbonatization, occurring as veins, veinlets, vesicle fillings and irregular patches of calcite, varies in magnitude of development but is widespread. Sericitization of feldspars and groundmass is only locally intense yet is generally present as incipient alteration throughout the district. The district-wide albitization of the Mantos Blancos volcanic sequence has altered what were originally more potassic and calcic, less sodic, rocks to what are now more properly referred to as keratophyres (Battey, 1955; Gilluly, 1935, Hughes, 1975). The petrographic and lithochemical characteristics of the three major alteration types noted above are summarized below.

Jan 1, 1984

By Tom B. Corry

INTRODUCTION Located approximately 48 km (30 miles) south of Dallas, Texas, use to be the site of the Superconducting Super Collider. For those of you unfamiliar with the project, this was a multi-billion dollar project taken on by the U.S. Government for the further advancement of technology, medicine, and science. Major components of the project consisted of a Linear Accelerator known as the LINAC; three accelerating rings known as the Low Energy Boosters (LEB), Medium Energy Booster (MEB) and the High Energy Booster (HEB); the East and West Campuses where the Inner Reactor Halls would have been located; and the 87 km (54 mile) main collider tunnel. Unfortunately, this all came to an end on December 6, 1993, with the termination of the project due to the Government's cancellation of funds. This paper will deal with the two of the underground contracts before the termination. These two contracts were the 1122 contract which ran from N25 to N40 and the 1130 contract which ran from N40 to N55. (See figure 1) The 1122 contract was awarded to us in July of 1992 and consisted of the excavation and support of six (6) shaft varying in diameter from 5.5 m (18 feet) to 8 m (26 feet) and ranging from 39.6 m (130 feet) to 61 m (200 feet) deep and the driving of approximately 13,100 m (.43,000 If.) of main collider tunnel. Our second contract, the 1130, was almost identical to our first

Jan 1, 1995

By Richard Snyder

Secretariat of the Coal Mining and Mining Executive Committees' of the National Safety Council (NSC) and Manager of the memberships to both Mining Sections; Senior Consulting Safety Engineer, NSC; member of several committees for consensus Standards of the American National Standards Institute (ANSI); a Certified Safety Professional (CSP) of the Board of Certified Safety Professionals of the Americas, Inc. and a chief proctor for CSP testing and certification procedures, et al. It appears that the tunneling trade is merging into its own renaissance for the decade of the 1970s', and most likely on past the year 2001. Federal interest in underground excavation, and more specifically, rapid excavation expertise has been on the upswing since the latter part of the 1960's, mainly due to the pressing national needs for more raw materials based on the rise for material goods and the projective gloom of possible power shortages. On the pure tunneling side the national needs encompass, in the mainstream of priorities, rapid transportation and water supply excavation as the two top contenders. For instance, the estimates for tunnel mileage for the period 1968-1975 are:(1) Subways---85 miles Urban Highways--- 123 miles Intercity Highways---210 miles Water Supply Routes---528 miles at a total of 946 miles of tunnels. The estimated cumulative underground excavation demand in dollar amounts for the period 1970-1989 are:(1) Construction Oriented Demand--- $35 billions Mining Oriented Demand---$34 billions (which includes the coal-oriented demand on the order of 26 billions.

Jan 1, 1997

By B. M. Kunar, C. S. N. Murthy, B. Rao K

Rock particle size has a very important significance in the mining industry, starting from blasting till the mineral processing. The present study was carried out to understand the particle size distribution in various sieves after conducting the ball milling process. The time of the grinding process was varied at different intervals. It was observed that 80% of the particles of both granite and marble rock samples passed through the 4800 μm sieve when subjected to grinding time of 40 minutes. Also, it was observed the number of particles that were retained in the smallest sieve of <75 μm was higher in the case of granite sample when compared to a marble sample. INTRODUCTION India is a major exporter of granite and marble stones. The major use of marbles and granites are constructing walls and floors. There are several machining processes that are applied before it is used as floors and walls. During this process, wastes are produced these wastes are used in various ways. These include use of powders for clay products (Segadães, Carvalho, & Acchar, 2005), as an additive in cement production (Aruntaş, Gürü, Dayi, & Tekin, 2010), to enhance the properties of brick ceramics (Saboya, Xavier, & Alexandre, 2007), in constructing bricks (Bilgin et al., 2012) and as an additive in concretes (Aliabdo, Abd Elmoaty, & Auda, 2014). Usually, the powder form of marble and granites are used as an additive in the above-mentioned applications. Powders of marble and granite are obtained through the grinding process. One such process of grinding is the ball milling process. In the ball milling process, a quantity of samples along with the charge quantity consisting of steel ball is subjected to a grinding process within a closed chamber as shown in Fig. 1. An even particle size can be obtained through sieving the material after subjecting it to grinding. The present study is planned to understand the particle size distribution in various sieves due to varying time and charge quantity in the experiment. Only time was varied to understand the amount of particle distribution in the case of granite and marble rock samples and a comparison is drawn. A statistical model was developed for marble rock specimen considering the data obtained by varying time and charge quantity in the ball mill experiment.

Jan 1, 2019

By C. J. Webb

Abandoned uranium mines in the southern Black Hills of South Dakota were sampled for uranium, radium, and rare earth elements during 1992 and 1993. Analyses of water samples from several shallow ponds in the mine pits showed pH values between 3 and 4 with uranium concentrations between 1600 and 2600 ppb. Rare earth elements and their respective isotopes were analyzed with an inductively coupled plasma mass spectrometer and were referenced to a shale normalization pattern. All samples showed an enrichment in the middle rare earth elements. Rare earth levels often were greater than 0.2 ppm. At one site, the concentrations of lanthanides were 150,000 times above background levels. While the southern Black Hills have long been known for rich uranium ore deposits, these analyses show that significant levels of rare earth elements also are present, indicating that the potential exist for future development.

Jan 1, 1995

By J. E. Jennings

The problems of slope stability in open-cast mines are examined. A criterion, the instantaneous stripping ratio, is suggested for use in the design of pit slopes and as an index of control at all stages of the exploitation of the ore body, This criterion may also be related to safety and to the maximizing of profits. Two approaches to safe design of slopes, one from the point of view of soil mechanics and the other from the point of view of rock mechanics, are described and critically compared. The effect on slope stability of the regional tectonic stress field is discussed. Explanation is given of the application of the Terzaghi effective stress concept to problems in both soil and rock environments, including possible effects when borehole deformation techniques are used to measure stresses in rock in situ.

Jan 1, 1963