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By R. E. Nivens

In the past, Newmont Gold Company relied on cement for their ore agglomeration process. With assistance from Betz Industrial, Newmont began Investigating the use of polymers for ore agglomeration. If gold recovery would not be jeopardized, then polymers could replace cement and possibly reduce operational costs associated with cement agglomeration. The following outlines the preliminary testing conducted to determine the feasibility of polymer agglomeration with Newmont's ore and the results of the test heap, which was constructed so the program could be examined under actual operating conditions. Similar polymer agglomeration testing has been successfully performed in other Nevada gold operations. By eliminating the need for cement, a polymeric agglomeration program could improve material handling operations, as well as offer the following additional savings. First, the polymer application uses only lime for adjusting basicity, the polymer does not contribute any alkalinity to the heap. Because lime is more soluble than cement, detoxification of the heap becomes much faster and less costly for the mine relative to rinsing cement alkalinity. The following graph compares the detoxification rate of cement and polymer over a 33 day cycle.

Jan 1, 1993

By Marlyn King, Kevin Peterson

Power Decks are voids created in the bottom of the borehole through the use of a suspended Super Plug. Explosive energy is started downward at initiation creating high pressures which find relief at the comers of the borehole cylinder in the bottom of the hole. This relief creates a horizontal break to the neighboring boreholes - the same effect as presplitting. This “presplit” represents a change of mass to.the explosive energy,and it is reflected upward in the more efficient form of tensile waves. This provides better use of the explosive energy than compression waves. This technique has created a new way of looking at the ways that explosive energy is transported through the rock mass.

Jan 1, 2002

By Gustavo E. Lagos

Mining is one of the oldest and most important productive activities in Chile. In the latter half of the 80's &d during the 1990's Chilean mining has experienced explosive growth fundamentally due to legislative changes which have encouraged an influx of foreign capital. Fine copper production has grown from 1,4 million tons in 1987 to 3,4 million tons in 1997. Gold production has increased from 17.03 tons in 1987 to 49.46 tons in 1997. In both cases private investment has driven this growth. The direct impact of mining on the Chilean economy has been considered one of the fundamental pillars of the growth of the country in the last years. The indirect impact that has generated on the other sectors of the Chilean economy and in particular the regional economies, has not been analyzed. This paper outlines a methodology for estimating the impact of mining investment and mining operations in different sectors of the Chilean economy at both regional and national levels. It applies this methodology to the case of Minera Escondida, the largest copper mine in the world, analyzing its economic impacts on the regional and national levels.

Jan 1, 1999

By Herbert F. Nyberg

The Black River Falls Mine is owned and operated by Jackson County Iron Company, a wholly owned subsidiary of Inland Steel Company. It is located in vest central Wisconsin, seven miles east of the city of Black River Falls. This is the first taconite plant in the state of Wisconsin. Iron mining started in this area in 1856 but soon failed due to the low grade ore and crude methods of mining and transportation. Inland Steel Company acquired the property in 1939. Some drilling and test work was done in 1940, but the economics of developing the property at that time were not favolable. Improved methods of concentrating and pelletizing in the 1960's made it possible to build the present plant. Due to the limited ore reserve of 45,000,000 tons with expected recovery of 33% it was necessary to limit the capacity of the operation to 750,000 TPY with a life of 20 years. There was some concern about an operation of such limited capacity. A million ton operation was considered the minimum size plant for a profitable operation.

Jan 1, 1976

By W. Randall, Robert M. Leary

Twin 1250 m (4100 ft.) long highway tunnels through Cumberland Mountain near Middlesboro, Kentucky are planned to be completed in the early 1990's. The tunnels will be excavated in sandstones, limestones, and shales, dipping at 35 to 50 degrees and striking nearly perpendicular to the tunnel alignment. In 1985-86 a pilot tunnel was excavated as a crown drift along the alignment of the southbound tunnel. The benefits of the pilot tunnel in reducing uncertainties for main tunnel construction are discussed. The cost-benefits of the pilot tunnel are examined in view of estimated main tunnel costs.

Jan 1, 1987

By E. Özberk

Uranium minerals are often associated with iron minerals, and during the hydrometallurgical processing of the uranium ores, iron plays several significant roles. The presence of Fe(III) in solution promotes the oxidative acid leaching for the recovery of uranium. The control of the distribution of impurities in milling and refining is also affected by dissolved iron. When rejected from the process streams, iron usually collects other impurities and contributes to the stabilization of the wastes for final disposal. These roles of iron, as they relate to current uranium processing operations, are discussed in detail, and some broad and historical perspectives are also presented.

Jan 1, 2006

By D A. Williams

The conventional method of transporting mine tailings from a process plant to a tailings storage facility (TSF) is in the form of a low to medium density1 slurry, which can be pumped using centrifugal pumps. Over the past several decades, therefore, mine operators have generally adopted this default approach. There are, however, some convincing arguments why consideration should be given to thickening the tailings slurry to a higher density paste consistency. In particular, the minimisation of environmental impacts, the reduction in water consumption and the cost savings relating to TSF closure make paste an attractive option for the life of mine tailings disposal. There are several environmental impacts that are associated with a conventional slurry TSF, such as land sterilisation, aesthetics, dust, seepage and acid mine drainage. Some of these impacts, such as dusting, may be difficult to mitigate while the TSF is in operation. Others can be influenced by adjustments made to the tailings slurry density at the plant. Unplanned fluctuations in slurry density and/or viscosity can have a significant influence on TSF performance and can exacerbate the environmental impacts relating to the facility. Relatively minor changes in the solids content of the slurry can affect tailings beaching behaviour, degree of segregation, position of the phreatic surface, amount of freeboard, consolidation behaviour, placed (settled) density (and hence TSF capacity) and in situ strength of the tailings. Paste is a non segregating slurry and many of these effects can be minimised at the TSF when the tailings slurry is thickened to a paste. These improvements are manifested by reduced seepage, flexibility in selecting an appropriate final landform, ability to rehabilitate progressively and reductions in plant water usage. It is possible to minimise environmental impacts of a TSF through the use of tailings paste. Ideally the paste production plant should be part of the initial design of the process plant. However, significant benefits can be gained by adding a paste production plant at some time later in the operational life of the mine to reduce environmental impacts and facilitate an environmentally acceptable TSF closure.

Jan 1, 2002

By C Muñoz, N Ortega, J Vergara, D Avilés

Mass blasts have been the subject of extensive studies because of their potential benefits in mining operations. However, it has not been possible to advance due to the paradigm that states that the blasts near the designed final wall or to critical structures have to be low tonnage. Another reason is the absence of specialised simulation programs to more precisely determine the influence of the energy released by blasting to the rock mass. There are some studies that demonstrate the possibility of massive blasting that maintain the design of the final slope (Farias and Santander, 2014). It should be noted that these studies develop the concept that the size of the blast should not increase the peak vibration in the rock mass.The study was carried out in partnership with Los Colorados Mining Company. Analysis, reconciliation and wall control for two types of blasts were performed:blasting production: approximately 850 000 t, with special wall control considerationsblasting of approximately 950 000 t over the entire width of the bench.Monitoring systems were used in the near field and far field using examination of holes in order to obtain information to assess the impact on the rock mass and then to compare these to conventional blasting combining production and contour blasting.The results show that for a large blasted volume, production and/or those generated from toe to crest on the bench did not produce more impact in the rock mass than the conventional blasting.The conclusions drawn from this study are:an improvement in the excavation rate of 7500 t/h that is higher than the maximum rates normally obtainedthe peak vibrations of the P wave generated by both blasts did not exceed the peak particle velocity criteria (Vergara and Muñoz, 2014)holes examination indicating no difference in their entire length, in pre- and post-blast reviewover US$2 000 000 savings generated in the year (estimated by the client) (Avilés, 2014).CITATION:Vergara, J, Muñoz, C, Ortega, N and Avilés, D, 2015. Benefits related to applications of a mass blast in open cut mining, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 625–632 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Henrique Paier Milanez

À medida que os depósitos minerais de alta qualidade vão se exaurindo e a contínua busca por menores custos operacionais aumentando, as rotas de beneficiamento de minério tornam-se mais complexas, gerando custos de capital cada vez maiores. Dessa forma, surgem desafios não somente para a redução desses custos, mas também para validação do dimensionamento dos equipamentos, teste das lógicas de controle, treinamento operacional e redução do tempo de start-up. No presente trabalho é realizada uma breve revisão bibliográfica sobre o atual cenário de simulação de processos na indústria mineral e é mostrado como essa tecnologia se encaixa em todas as etapas do desenvolvimento de projetos. Especificamente, são apresentados estudos de dimensionamento de linhas de processo e dimensionamento de bombas centrífugas em casos técnicos em que o software IDEAS foi utilizado como ferramenta de simulação dinâmica para validação do processo, reduzindo o impacto financeiro em etapas posteriores. Como exemplo dos resultados das validações, mais de 40 bombas tiveram seu dimensionamento reavaliado e mais de 10 tubulações tiveram seus diâmetros revisados. Os resultados observados corroboram o grande potencial tanto da ferramenta computacional, quanto da simulação de processos de modo geral.

Jul 30, 2018

By AIME AIME

BBENJAMIN LEROY MILLER, of geology at Lehigh since 1907, is known the world around, for his former students are on every continent. He knows the earth is round for he has encircled it twice, once in 1927, and the other way around in 1937 to regain the day he lost on the first trip. An early trip was to Great Britain and Ireland, another to central Europe, a third to Spain for the International Geological Congress, a fourth to Scandinavia. His trip to the Southern Hemisphere is recorded in "Mineral Deposits of South America." In 1940 he was booked for Australia but because of the war went instead to Alaska. He spent the summer of 1941 in Central America. Thus he has gained a broad. world knowledge of mineral deposits, both metallic and nonmetallic.

Jan 1, 1942

"Coupon testing has been used to investigate stress corrosion cracking (SCC) of rockbolts in a laboratory based experimental program. This program has focused on the use of ASTM G39 three- and four-point bent beam coupon specimens, immersed in an acidified sodium chloride test solution containing hydrogen sulfide. The specimens were loaded to a range of stresses from zero, to just above the materials yield strength. It was found that only specimens above an applied stress of 580MPa failed by means of SCC, showing that rockbolts loaded to near their yield strength may be susceptible to SCC in-situ.INTRODUCTIONStress corrosion cracking (SCC) is a failure mechanism that affects material through the growth of hairline cracks when exposed to a corrosive medium while under stress (Jones and Ricker, 1999). SCC has been found to affect rockbolts in the Australian underground coal mining industry and has the capacity to cause the catastrophic failure of ground support systems, potentially leading to falls of ground in underground excavations, injury or death to mine personnel, damage or loss of equipment, and loss of productivity through the loss of roadway access (Crosky et al, 2002).Coupon testing utilises small scale samples that are intended to be indicative of the behaviour exhibited by a material in-situ (ASTM G39). The small scale, and usually high surface area to volume ratio of coupon specimens mean that they corrode at faster rate proportional to their mass, greatly reducing testing times. The small scale of the specimens allows them to be more easily prepared and handled, loaning them to mass manufacturing techniques.A previous study conducted by Vandermaat et al (2012b) into the use of three- and four-point coupon testing in-situ in an underground coal mine failed to result in SCC of the specimens. This paper serves as a follow up laboratory investigation in order to understand why these specimens did not fail. Previous studies into the SCC in rockbolts carried out by Gamboa and Atrens (2003) determined that rockbolt steel has a critical stress threshold of approximately 90% of the material ultimate tensile strength (800-900MPa). This study will focus on this critical stress threshold as a possible explanation for the lack of failure in the in-situ specimens (Vandermaat, 2012b)."

Jan 1, 2015

By J. Dubinski

Passive tomographic imaging is a technique that can be used for assessing seismic hazard in mines with high seismic activity induced by mining. The basic idea behind such an interpretation is the assumption that there is a relationship between high values of seismic velocity and high values of stresses in the rock mass. This relationship was confirmed both in laboratory an in situ measurements and constitutes the basis for rock-burst and seismic hazard evaluation. In the paper seismic tomographic images of seismic P wave velocity and seismic P wave velocity gradient have been presented to determine rock-burst hazard and locate high seismic activity zones in the area of coal panel 306 in Zabrze Bielszowice mine. The zones of high values of P-wave seismic velocity gradient have been found to correlate with the distribution of high energetic seismic events. Passive tomographic images were obtained using modern bent ray tracing tomography algorithm with regularization. Recent study give rise to observation that not only high values of P-wave seismic velocity is important in seismic hazard assessment as many strong seismic events are located in the areas of high values of velocity gradient. This recent observation permits to increase quality of passive tomographic imaging for detection of seismogenic zones and is presented in the paper. The advantage of passive tomography comparing to active tomography is that sources of seismic waves are generated by rock mass itself and costly controlled explosions are not necessary. Another practical limitation of active tomography is the size of study area which usually do not exceed 200 m by 200 m. This restriction does not appear in passive tomography where area of study is usually 2000 m by 2000 m and the tomographic images delineate velocity structure in locations where mining induced seismicity take place. Passive tomography method utilized in analysis of rock mass state in underground mines encounter some difficulties concerned with the numerical stability of optimization algorithms. In the presented approach to passive tomography problem numerical stability is obtained by special regularization method and by application of very stable numerical seismic ray-tracing algorithm.

Aug 1, 2013

By Joseph L. Gillson

Bentonite, designating a distinct type of clay, is a young name in mineral nomenclature in the light of the age-old names of most other useful nonmetallics. The earliest references in literature are to "soap clay" (1873) "taylorite" (1888) and finally "bentonite" in 1897, from its occurrence in the Fort Benton series of rocks near Rock Creek, Albany County, Wyoming. Bentonite is a rock term and consists largely of montmorillonite clay. The latter name was proposed in 1847 for a plastic clay found at Montmorillon, France. A clay of apparently identical properties was described by Cronstedt of Sweden in 1788 and a number of other similar clays found in France were given other names in publications from 1853 to 1856. The mineral name montmorillonite was recognized by Dana in 1892. The recognition of "clay mineral" distinctions which led to the present-day classifications of clays by their chief mineral content, dawned in the early part of the twentieth century. Grim6 has aptly said: About 1924, Ross10 and some colleagues of the U. S. Geological Survey began a study of the mineral composition of clays that led to a series of monumental papers on the subject. By the early 1930's what has come to be known as the clay-mineral concept became firmly established in the minds of a great many people actively studying clay materials. The clay mineral concept designates the major clays as kaolins, montmorillonites and illites and by this concept bentonites are now defined as "fine-grained clays containing not less than 85 pct montmorillonite" and a wide variety of clays found all over the world are included in that classification. They could all properly be called "montmorillonite clays" but the common commercial name is bentonite. For a period of over forty years from the time of the earlier discoveries, bentonite was thought to be only the sodium type highswelling clay produced principally in Wyoming. By the clay mineral concept, non-swelling montmorillonite clays also became known as bentonite. In the trade there are two broad divisions-sodium bentonite, often called Wyoming or "western," which expands in water and carries sodium as its predominant exchangeable ion, and calcium bentonite often called "southern," which has negligible swelling and carries calcium as its principal exchangeable ion. There are many intermediate gradations. Properties The mineralogy and chemistry of the clays are so complex that the subject cannot be summarized briefly. The reader is referred to Chapter 12 of this volume in which the subject is treated at some length. Grim6 gave the formula for montmorillonite as (OH)4Si8AL4020.nH2O. He wrote: Montmorillonite is composed of units made up of two silica tetrahedral sheets with a central alumina octahedral sheet. . . . Exchangeable rations occur between the silicate layers. . . . The words "tetrahedral" and "octahedral" refer to the coordination number of the cations in the unit cell in the crystallographic lattice. Carroll5a stated: That the montmorillonite structure is the same as that of mica, but the layers are not held together by K+ ions; and water and other polar molecules, such as organic molecules, can enter between the unit layers and cause expansion. Ex-

Jan 1, 1960

By Paul Bechtner

THE name bentonite formerly was applied solely to a peculiar clay occurring in Wyoming and South Dakota, which was distinguished from other clays by its unctuous feel when wet and the property of swelling in water. In the last decade scientific studies of clay have recognized that bentonite is composed mainly of the clay mineral montmorillonite and the name bentonite has been extended to cover the entire family of clays that have montmorillonite as their chief constituent. Montmorillonite has the chemical formula of A1203-4Si0-xH2O, With Fe203 and MgO replacing part of the A1203. The montmorillonite crystal is an Si-Al-Si clay mineral, being formed of two silicon-oxygen sheets with an aluminum-oxygen sheet sandwiched between them. In contrast, kaolinite-the chief clay mineral of most clays other than bentonite-is Si-Al, one silica and one alumina sheet. The unit crystal of montmorillonite is much thinner than that of kaolinite, with greater surface area. These differences in crystal structure patterns are leading factors in the dissimilar properties and commercial uses of bentonite compared with other clays. Mineralogically, bentonites are 85 to 90 pct montmorillonite with fragments of feldspar, gypsum, calcium carbonate, quartz and traces of other minerals. They vary in color; the widely used Wyoming type is creamy white when dry and a light shade of tan when wet; the low-swelling bentonites of the southern United States and elsewhere are found in many shades of gray, blue, yellow, red, and brown. Pure white bentonites are rarer and generally of the medium or low-swelling type, though there are a few exceptions to that general rule. PROPERTIES Bentonites may be divided into two general classes: (1) those that adsorb large quantities of water, "swelling" greatly in the process, and that remain in suspension in thin water dispersions; (2) those that adsorb only slightly more water than ordinary plastic clays or fuller's earths, do not swell noticeably, and settle rapidly in thin water dispersions. Another distinction is that some varieties of the No. 2 type

Jan 1, 1949

By H. G. Fleshman

Thousands of years ago, Chinese water well drillers developed a technique for punching holes in the ground by lifting massive metal bits and letting them fall against the rock. With diligence, they could pound away about 2 feet a day. The Chinese drillers pounded holes in the ground this way for almost 2000 years. In the 1860's, French water well drillers developed a perforated bit moistened by fluids pumped into the hole through a hollow rod. The fluids carried the cuttings from the hole and spared the Frenchmen the task of bailing them out by hand.

Jan 1, 1986

By See G. T

Bentonites and fuller's earths from seven localities in N.S.W. have been analysed with respect to occurrence, mineralogy and physical properties and areas for future prospecting have been indicated.INTRODUCTIONThe rapid expansion of Australian industry in the postwar years has been accompanied by an ever increasing demand for fuller's earth and bentonite, but in New South Wales at least the demand has been met principally by imports. However, some local and generally inferior active earths have been won to blend with imported materials to reduce costs. The important discovery of the widespread distribution of bentonite clays in the Northern Coal Measures, made recently by Grim (Booker, 1956), has givenimpetus to the further search for material comparable in quality to the imported active earths.Bentonite may be defined as a highly plastic clay, generally possessing swelling properties, composed essentially of montmorillonite and derived from the alteration of volcanic ash. Fuller's earth refers to any clay which, with or without chemical treatment, is capable of decolourizing mineral or vegetable oils and is, therefore of economic value. Montmorillonite is the active component of most fuller's earths, though palygorskite-, halloysite- and even kaolinite-rich clays have been used.Previous literature related to the New South Wales deposits has been confined to general descriptions and little technical data beyond an occasional chemical analysIs have been available. Bentonites and fuller's earths from seven...

Jan 1, 1959

By Giles C. N, Loughnan F. C

Bentonites and active earths from N.S.W., previously analysed with respect to occurrence, mineralogy and physical properties have been evaluated for use as bonding agents in quartzose moulding sands in terms of green properties and behaviour both with and without coal dust for iron castings poured at 1400°C.INTRODUCTIONIn the paper by Loughnan .and See (Part I) the occurrence, mineralogy and physical properties of the fuller's earth and bentonites of New South Wales were discussed and it was shown that some of the materials approached the quality of Wyoming bentonite. In the present paper the same samples from Marulan (Bl), Boggabri (B2), Wingen (B3), Muswellbrook (B6), Swansea (B8), Dubbo (89) and Trida (Bll) have been investigated with respect to their potential value as bonding agents in compounded moulding sands. Inaddition, the -20 micron fractions of the Boggabri (B2t) and Swansea (B8t,> were recovered and the former converted to a sodium clay, in order to assesE; the beneficiation possibilities. A sample of Wyoming bentonite (S2) also has been included for comparison.GREEN PROPERTIES OF THE ARTIFICIAL MOULDING SANDSA quartzose base sand (Botany Dune) previously oven pried and screened to 1·65 mm., was subjected to a sieve ana]ysis in accordance with standard A.F.A. practice to yield a calculated' fineness number of 45. All tests were carried out on mixtures of this sand with2t per cent clay, since such mixtures were found most suit...

Jan 1, 1959

By Ted H. Eyde

Specialty sand and bentonite are produced in the plateau province from the Bidahochi Formation near Sanders, Apache County, Arizona. It appears that deposits of both sand and bentonite formed during the Pliocene in fluvial and lacustrine environments, respectively, along the west side of the Defiance Uplift. The bentonite is an alteration product of airborne vitric ash that fell or was washed into lakes. In the Cheto district, the individual bentonite horizons, which range from less than a foot to more than 10 feet thick, are restricted to the position of the medial volcanic member. Bentonite production began at the Allentown mine in 1924 and the Chambers mine in 1926. In 1933 strip mining of the extensive deposits in the Cheto district commenced. Production increased each year to a peak of 270,000 tons in 1957. As a result of the introduction of synthetic zeolites into petroleum refining, production declined. About 40,000 tons of bentonite are currently produced from the district each year. Bentonite is shipped out of State for processing into desiccants, thickeners, and acid-activated clay products. The specialty sand was derived from Permian sandstones and deposited by streams draining the Defiance Uplift. Although stream channels are usually restricted to the upper member of the Bidahochi, stratigraphically above the bentonite horizon, a few actually cut through the bentonite. The well-sorted sand, suitable for use as a proppant in hydraulically fractured oil and gas wells, is localized in elongate lenses along the margins of the channels. These lenses range from 5 to 50 feet in thickness and often extend thousands of feet in both width and length. The sand is about 97 percent silica, has a yield of 40 percent in the minus 20 plus 40 mesh size fraction, and has a roundness of 0.6 to 0.7 on the Krumbein scale. Production of this sand began about 1961. All of the current production, which amounts to about 40,000 tons per year, is sold in the petroleum-producing area near Farmington, New Mexico.

Jan 1, 1987

By S. K. Kawatra, S. J. Ripke

Iron ore pellets use bentonite clay as binder at dosages from 0.5to 1.0% (10 to 20 pounds per ton) of moist iron ore concentrate. Bentonite is typically shipped hundreds of miles from Wyoming to the Lake Superior iron ore district. It is therefore best to know how effective a bentonite will be before it is shipped and used to bind concentrate into pellets. Current tests of bentonite effectiveness include: plate water absorption, methylene blue uptake, free swell, exchangeable cations, and glycolated layer expansion. However, these tests have many disadvantages: First, they only measure the ability of a bentonite to expand, disperse, or absorb, not how well it will bond. Second, most of the tests require up to 20 hours to perform. Bentonite only has a few minutes to interact within the concentrate before it is indurated (sintered). These long-term tests may not reflect the true behavior of bentonite. Third, the tests are tedious and often results are inconsistent between different iron ore concentrates, labs, and technicians. Fourth, some of the testing equipment is difficult to procure. Fifth, procedures are often difficult to standardize. In this paper, the Binder Effectiveness Strength (BESt) test to evaluate binders for iron ore pellets is presented that: measures the ability of bentonite to bond, requires only about two hours to complete, is simple and reproducible, and utilizes readily available equipment that has been standardized for decades.

Jan 1, 2003

By G. Bulut

The aim of this study is to produce desiccant clay from a well known Ca-bentonite deposit in Turkey. Towards this aim, bentonite samples were first procured and then subjected to some characterization tests. Various methods were applied to enhance the moisture adsorption capacity of bentonites to a desirable level. These methods include utilization of some additives namely calcium chloride and heat treatment at various temperatures. It is shown that the moisture adsorption capacity Ca-bentonites without any additive are between 14%~17 % (w/w) upon by heat treatment whereas the addition of calcium chloride significantly, raised the moisture adsorption capacities.

Jan 1, 2014