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By Omid Asghari, Seyed Reza Ghavami-Riabi, Sajjad Talesh Hosseini

Separation of geochemical anomalies from the background using various methods for identifying areas of higher mineral potential is a critical first step in Greenfield and Brownfield programs. There are several methods for differentiating anomalous regions from the background. The U-spatial statistics is an effective technique that provides the opportunity of reaching this goal by considering the geochemical sample locations in the separation of geochemical anomalies. In this study, a developed form of the U-spatial statistics method is introduced, which not only considers the existence of anisotropic spatial variations in input data but also reduces the computational (CPU) time. While the previous method is based on the isotropic assumption in the study area and a set of search windows at different times, here, the geochemical anomaly is determined by pasting only one ellipsoid window, effectively combining the flexibility of the U-spatial statistics method with the advantages of geostatistical approaches. This paper compares various approaches (the previous and developed version of the U-spatial statistics method, concentrationarea (C–A) fractal model, and probability diagram modeling) for the separation of anomalous areas in the presence of heterogeneous spatial variations. This is done with an application to a Baghqloom porphyry copper deposit located in southeastern Iran. The high potential areas identified via different approaches show an anomalous region in central parts of the Baghqloom area, which partially coincides with an intense potassic alteration area. Compared to other methods, our algorithm separated the high potential areas at a greater spatial resolution.

May 3, 2021

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

The integrated grouting method, as developed in the USSR, can be applied to multi-purpose operations that in¬clude the construction of shafts, drifts, and tunnels. In the USSR it has been used extensively for primary and final grouting of underground excavations in mining engineering and civil engineering projects. It has been applied in projects where the primary objective was waste contain¬ment. It has also been used to control subsidence beneath buildings located over mined out openings and to eliminate the flow of ground water beneath and around dams. This chapter considers several industrial applications in the form of case histories. The word integrated means that grouting activities were integrated with other activities. 9.1 CASE HISTORIES OF GROUTING FRACTURED ROCK WHEN SINKING VERTICAL SHAFTS The integrated grouting method has been applied most widely in the sinking of vertical shafts in fractured, satu¬rated rock. As explained previously herein, grouting oper¬ations preferably are carried out from the ground surface where they are integrated into the schedule of the setting up of the shaft excavation and construction equipment. Such integration reduces significantly the length of time required for preparation of shaft construction and the time required to sink the shaft. The increased efficiency is achieved by the elimination of cementing operations from the working face upon the penetration of each aquifer. Concomitantly, labor and energy consumption during shaft sinking are minimized because the more complicated and labor-intensive work is carried out at the surface section. Table 9.1 presents the essential parameters for the pri¬mary grouting of saturated fractured rock carried out by the integrated method when sinking vertical shafts. 9.1.1 NAGOL'CHANSK MINE NO. 1-2, VENTILATION SHAFT NO. 1 The integrated method of grouting saturated fractured rock through holes drilled from the surface was employed for the first time during the sinking of vertical shaft No. 1 at the Nagol'chansk mine No. 1-2 in the Don Basin. The shaft had an inside diameter of 6 m. The grouting operations commenced by using cement grout with a density of 1.7 to 1.8 g/cm3. Clay-based grout with cement and other addi¬tives was used only for grouting the aquifers where cement grout proved to be ineffective. By the time of the grouting of ventilation shaft No. 1, hydrodynamic analytical methods were well in hand and a preliminary method for designing isolation curtains had been developed. A method for designing and drilling ori¬ented directional drillholes whose natural curvature re¬flected the characteristics of the fracturing had been devel¬oped. The majority of the necessary equipment had been developed. Clay-based grouts were considered ready for the first industrial application. The hydrogeologic environment at the Nagol'chansk mine No. 1-2 contained many prolific aquifers. According to monitored drillhole data, the total expected inflow into ventilation shaft No. 1 without grouting was 425 m3/hr. This large ground water inflow rate was supported by in¬formation obtained during the sinking of the main shaft and from the auxiliary shaft of the "Nagol'chansk" mine No. 1-2. The construction contractor at the site began sinking ventilation shaft No. 1 to a depth of 217 m by cement grouting from the working face of the shaft. As a result of the cement grouting operations, the inflow of water was reduced from 105.4 to 40 m3/hr over this 217 m interval. However the residual inflow rate caused the shaft to become functional at the depth of 217 m. At this point all grouting operations were transferred to SPETSTAMPONAZHGEOLOGIA (STG) in an effort to improve the operation. In order to carry out preliminary grouting from the sur¬face, seven drillholes were installed and designed for re¬ceiving grout. Drilling was implemented by the ZIF-1200A rig to the design depth of the shaft. The geometry of the principal fracture system that would be encountered by the shaft was estimated while breaking ground using informa¬tion from other shafts. The drillholes were arranged so that they cut through the aquifers uniformly around the shaft. Some preference was given to intercepting the aquifers that were located along the rock dip above the shaft bottom because it was established that the ground water in the aqui¬fers flowed downward along the dip into the cone of de¬pression of the shaft. Investigations in the drillholes using the DAU-3M flowmeter described in Chapter 3 showed that all of the nine aquifers were penetrated by the time a depth of 690 m had been reached. The flowmetric information showed that aquifer numbers [1 and 2], [4, 5, and 6], and [7 and 8] had practically identical hydrogeologic characteristics; so it was decided to connect them into combined stopes and inject the grout using five stopes instead of nine. Table 9.2 shows the results of the grout injection into the aquifers. The volume of grout pumped into the separate intervals through single holes varied from 204 to 15 m3. The trend of grout consumption showed a reduction of grout consump

Jan 1, 1993

By K. Chandrasekaran

Carbon-in-leach (CIL) is conventionally used in gold processing operations when preg robbing components are present in the ore. The CIL process is becoming attractive even in other situations when preg robbing is not a factor. This article discusses the situations in which the CIL circuit can be applied. The results of leach-carbon-in-pulp (CIP) and CIL circuits at Newmont Gold's Mill No. 2, No. 4 and No. 5 are presented for comparison: Mill No. 4 was initially designed for a throughput of 4.1 kt/d (4500 stpd). It is presently operating at an average throughput of 6.6 kt/d (7300 stpd) without significant changes to the original design. The design considerations of the Mill No. 4 CIL circuit are discussed. The design of any processing facility represents a series of decisions. The final design options should ultimately be resolved based on economic as well as technical considerations. Every design decision represents some sort of compromise. From the designer's view point, these decisions are made with the conviction that the final product represents the most prudent long-term expenditure. The design throughput rate is a decision reflecting a maximum return for the capital and operating costs that the plant will incur over the life of the mineral resource. The result is a plant that is not operator proof or maintenance free because it would be too costly to build. At some point, the incremental increase in the level of capital expenditure would not adequately compensate for the lower

Jan 1, 1991

By W. K. Wedge

The chemical composition of the Pennsylvanian Bethany Falls Limestone Member of the Swope Formation was investigated using optical emission spectroscopy and both flame and flameless atomic absorption spectroscopy. Elements determined were Ca, Mg, Fe, Mn, AI, Si, Na, K, P, Ti, Zn, Cd, Ni, Co, Cu, Pb, Cr, V, and Mo. Over 100 samples were collected from active quarries along a 320-km-long (200-mile) outcrop in northwestern Missouri. Intervals were sampled representing uniform lithology to determine vertical and lateral geochemical variation. The Bethany Falls Limestone is the most extensively quarried Pennsylvanian limestone in Missouri. In 1975, 42 active quarries produced almost 5.4 million tons (6 million st) of stone valued at over 15 million dollars.

Jan 1, 1977

By Pedro D. Lasota

Chile leads the world in copper production with an annual capacity nearing 2 Mt (2.2 million st). Most of the country’s copper production, about 74%, is mined by open-pit mining methods. Open-pit mining also accounts for a major portion of Chile’s production of other commodities, including iron, gold, silver and coal (Table 1). Chile’s mining boom began 10 years ago and is expected to continue through the end of the decade. From 1980 to 1990, copper production in Chile increased 48.7%. During the same period, gold production increased 303%, silver production increased 119% and coal and iron ore production increased 163.7% and 6.6%, respectively (Table 2). It is estimated that copper production will be in the order of 2.3 Mt (2.5 million st) by 1996, when new projects now under construction come onstream. Gold production could reach 35 t (1.1 million oz) and coal production could increase another 1 Mt/a (1.1 million stpy). Open-pit mining has played a significant role in Chile’s minerals production growth. The expected increases in mine operations will come about mainly through new open pits or expansions of existing surface operations (Table 3). However, the number of open-pit copper mines will decrease from 74% to 66% of the total number of Chilean mines. Gold mines will increase from 63% to 69% of the total, while coal mines will go from 41% to 59%. Most all of the present iron ore production is from surface mines and will continue that way.

Jan 1, 1992

By Aditya Rana, A. K. Mishra, M. M. Singh, N. K. Bhagat

Many cases of derailments, train accidents and traffic interruptions due to the slope failure and rockfall have been reported in the past on Konkan Railway trackline because of unstable rock slopes. The authorities installed stability enhancement measures such as wire netting, rock bolting and shotcreting which were found insufficient. The failed geotechnical measures prompted authorities to excavate the unstable slopes. Rock blasting is generally not preferred for the excavation of slopes along the transportation route. Stabilisation and widening of slopes by blasting need closure of the route for a considerable time. Discontinuing traffic on Konkan Railway route was undesirable as it connects two important port cities Mumbai and Mangalore. The paper presents an innovative directional controlled blasting (DCB) technique for excavating three unstable slopes (i.e. cuttings) in hilly terrain without disturbing the traffic. New empirical formulae for small geometry blasting to estimate burden and throw have been developed. A unique sequence of firing and excavation with powder factor varying between 0.04 and 0.39 kg/m3 irrespective of the actual free face was used for rock blasting. The process controlled the throw of blasted material over the track and resulted in a smooth and stable wall. The slope angle has been changed from 80 to 82° to 45–47° and probability of wedge, planar and toppling failures was eliminated. About 100 such accident-prone slopes (52 km cumulative length, 7% of total route) situated at discrete locations along Konkan Railway route were stabilised using the technique. No incident of rockfall and slope failures along these slopes has been observed after the stabilisation.

By F. B. Henderson, D. Bird, P. L. Hauff, E. C. Prosh

A National Aeronautics and Space Administration (NASA)-funded project (NASA Grant #NAG13-02026) is underway to determine the ability of hyperspectral remote sensing to map mineralogy that affects water quality within a watershed and to identify the relative contributions of natural and anthropogenic sources to that drainage. Natural sources, particularly areas of pyritic hydrothermal alteration, have been found by the Colorado Geological Survey to be a significant source, sometimes the only source, for acidity and/or metals in a number of areas of Colorado (Neubert, 2000). This situation undoubtedly occurs in many places in the Western United States and elsewhere where metallic mineralization occurs. Anthropogenic sources arise from mining and other human activities that increase the exposure of acid-generating materials to weathering processes, thereby increasing acidity and metal loading to drainages where that activity is occurring or has occurred. This project is attempting to determine if these sources can be differentiated through mineralogical analysis, in conjunction with surface water chemistry that controls the precipitated minerals, of the impacted drainages by remote sensing techniques.

Jan 1, 2003

By Hongjie Yu, Mike Mooney

Transitions between geological/geotechnical soil units have a critical impact on the operation and performance of a tunnel boring machine (TBM). Geostatistics-based probabilistic modeling is used to quantify the uncertainty in soil transition locations. This paper presents two unique soft-ground tunneling case studies where the results from the geostatistics-based probabilistic modeling are compared to the TBM data and as-encountered ground conditions derived from the actual TBM data. The assessment enhances the confidence in using geostatistics to improve ground awareness for efficient tunnel construction, minimizing different site condition (DSC) claims, and improving decision-making on tunnel projects.

Dec 1, 2022

By D. G. Kotlyar

Oxidized sulfide minerals, commonly formed by weathering, increasingly are becoming important resources as primary sulfide deposits are depleted. Oxidation, in general, reduces selectivity and recovery in flotation. The objective of this research was to determine the mechanisms of oxidation and collector adsorption in sulfide systems as a step towards developing improved technologies for beneficiation of oxidized sulfides. Data from microcell flotation tests are combined with electrochemical and spectrophotometric measurements. The adsorption of ethyl xanthate (EX) on oxidized sulfides was characterized using AC impedance techniques and correlated to flotation response. The floatability of chalcocite, chalcopyrite and pyrite was dependent on the extent of oxidation. Oxidation for 1?) d at 65? C inhibited flotation of chalcocite, and chalcopyrite even after the addition of a large amount (1 x 10') M) of collector. Heavily oxidized (27 d) chalcocite remained unfloatable. However, longer oxidation of pyrite and chalcopyrite restored the floatability. Oxidation resulted in an electrically resistive, nonporous surface layer.

Jan 1, 1993

By K. F. Clark

Some 30 years ago Stevenson (1940) underscored the fact that most of the world's molybdenite production came from the Cordillera that comprise the western part of North America, and that the northern extension of the Cordillera into British Columbia is not essentially dissimilar to the United States section. Therefore, in view of the successful development of molybdenite resources in the United States, he concluded that prospecting in the Canadian section f the Cordillera should be encouraged. However, as recently as seven years ago Schneider (1963) remarks that no large economic deposits have been brought into production in British Columbia, although one important property was being evaluated. World production f molybdenum ore was sporadic until 1900. Among the very early producing areas in North America were Arizona and New Mexico in the United States. World War I provided the stimulus that brought the Climax deposit into production, and in 1920 Questa, New Mexico followed, although the ore came from fissure vein deposits at that time. In the early part f this century high grade deposits in various parts f the world containing 5-20 percent MoS2 were exploited. In Canada most production during World War I came from Quebec and Ontario. With the build-up of world tension and the inception f hostilities in 1939, British demand was satisfied by United States producers (Schneider, 1963).

Jan 1, 1970

By F. G. Miller

It is generally accepted that sulfur exists in coal in three forms: (1) pyritic, (2) organic, and (3) sulfate sulfur. Sulfate sulfur usually makes up less than 1% of the total sulfur content. Pyritic and organic sulfur, make up almost all of the total sulfur and occur in varying amounts in different coals and can vary greatly in coal of the same seam Pyritic sulfurs of 20% to 80% of the total sulfur have been reported Other authors have shown that it is not possible to remove the organic sulfur without chemically altering the coal. Chapman and Jones (1) state: "Organic sulfur, unlike pyritic sulfur does not exist as discrete particles, but is intimately associated with the coal structure, and as such it is not possible to remove it or reduce its concentration by physical means." Any success in removing sulfur has come about by removing pyritic sulfur by physical means; therefore, removal of sulfur in the pyritic form is the subject of this investigation. The extent to which any impurities can be removed from a particular coal can be determined by a washability study. Outside of crushing coal, to finer sizes or chemically altering the coal, there are no known methods of changing this inherent washability characteristic. The efficiency of various methods used to remove impurities can be determined by comparison of results produced at a yield to the results as shown by a washability study. In recent years heavy media processes have proven their ability to wash plus 28 mesh coal and nearly produce results shown to be theoretically possible by the washability study. Therefore, it is the objective of this paper to show various methods of treating the finer fractions of the coal, in the hope of developing a process, which can effectively produce in the fine fractions the efficiency of heavy media devices in the coarse.

Jan 1, 1963

By Nikhil Dhawan, Shrey Agrawal

Feldspar, a low-alumina, and abundantly available aluminosilicate source, is explored in this study to extract aluminum and potassium values. The sample comprises lamellar layers of microcline and albite with quartz containing 17.4% Al2O3, 9.67% K2O, and 66.3% SiO2. Mechanical (milling) and thermal (alkali and acid baking) activation are investigated, followed by HCl leaching. The milling treatment up to 6 h is inefficient in phase dissociation and results in ~ 40% Al and K dissolution. The alkali thermal treatment yielded 80% Al and 71% K extraction. Direct precipitation of the dissolved Al and Si values yielded alumina purity of ~ 29%, and silica gelation separated SiO2 and improved alumina product (94% purity, 71% recovery). Acid baking yielded 98% pure alumina precipitate; however, Al and K extraction were limited to ~ 45% and 65%, respectively. The microwave-assisted alkali treatment was optimal with 800 W and 10 min processing conditions yielding 80% Al and 71% K recovery with 2.26 kWh/kg alumina of thermal energy consumption. The final product contains γ-alumina with a specific surface area of 87 m2/ g. Keywords Feldspar · Alumina · Potassium ·

May 18, 2022

By Donald P. Tuchman, Emanuele G. Cauda, Steven E. Mischler, Elaine N. Rubinstein, Jay F. Colinet

The PDM3600 and PDM3700 are two closely related person-wearable dust monitors manufactured by Thermo Fisher Scientific. Both are based on tapered element oscillating microbalance technology and provide nearly real-time, mass-based readings of respirable dust concentrations. From a monitoring perspective, the primary difference between the models is the PDM3600 has an integrated cap lamp with attached inlet, while the PDM3700 has no cap lamp and a revised inlet attaches to the worker’s lapel. Using coals of varied origin and employing a wide range of concentrations, side-by-side measurements from these instruments were collected under controlled laboratory conditions and then compared. By use of ordinary least squares and weighted least squares regression methods, followed by mixed model analysis, results suggest there is no statistically significant or practical difference in instrument performance. The two monitors are equivalent for the field dust concentration measurements for which they were designed.

Feb 28, 2024

By Karoly C. Kocsis, Kyle A. Scalise, Marcelo Bandeira Teixeira

Understanding the effects of various ventilation and climatic parameters on the work conditions and comfort in underground mines is critical for efficient ventilation system design and cost savings and to ensure the health and safety of mine workers. To understand the effects that the thermal damping effect (TDE) and the thermal flywheel effect (TFE) have on the ventilation system design and potential cooling system, this paper compares and analyzes the wet and dry-bulb temperatures at the bottom of an intake shaft using two modeling software packages, Ventsim™ and Climsim™. The comparison shows the consequences and importance of taking into account the TDE/TFE when predicting the climatic conditions in future underground mines, especially when deciding on whether a cooling system should be employed in order to provide adequate climatic conditions in the production stopes, dead-end development headings, and throughout the mine. Ventsim™is able to account for the TFE, while Climsim™does not. Both software packages have their uses and are used within the mining industry, but it is useful to understand their limitations and where the future of underground climatic modeling will lead.

Oct 9, 2020

By Peter L. Comanor

At Getchell, Nevada a thousand tons per day mill for extracting gold from an ore containing orpiment and realgar was operated several years until early 1967. A cyanide process with a roaster was used in the processing of the ore. Mill wastes were contained in tailings ponds, in which the concentration of arsenic, currently, is one per cent or higher, Studies were conducted determining the effect of the tailing wastes on the Upper Sonoran vegetation of the area. Grid and line-intercept techniques were employed to obtain botanical informatics of the area surrounding the tailings ponds. Data of the per cent ground cover, species frequency, and plant vitality as a function of distance from the tailings ponds was collected. The data was compared to other botanical data collected from a control site outside the influence of the tailings ponds. In an attempt to isolate naturally occurring factors for varying plant communities from hose induced by factors derived from the close proximity of the tailings, soil cores were taken along the line-intercepts at intervals of 30 meters. The cores were analyzed for several compounds and elements needed for growth, or known to inhibit growth. Specific physical parameters of the soil samples were also taken. The paper describes the impact made by mill wastes containing large amounts of arsenic on the Upper Sonoran vegetation of the Getchell region. Described in detail are the techniques used to make the correlations between the plant communities and the influences of mill wastes.

Jan 1, 1974

By S. Chander

A series of nonionic and anionic surfactants were tested to enhance the flotation response of a low rank coal. An ethoxylated octyl phenol and several polypropylene polyethylene block copolymers were tested as nonionic surfactants. The anionic surfactant was a dioctyl sulfosuccinate. All the surfactants employed improved the yield significantly but the influence on grade was complex. Separate studies were conducted to determine the emulsification behavior of the surfactants. For the nonionic water soluble reagents tested, a correlation between emulsifying power of the surfactant and flotation was observed. An increase in the number of droplets produced in surfactant containing systems was considered to be the main reason for increase in the yield. Since it increased the number of collisions between dodecane droplets and coal particles. When a surfactant was introduced into the flotation pulp prior to addition of dodecane, it decreased the benefits of the surfactant significantly. The decrease was attributed to an increase in the wettability of coal and a decrease in the surfactant available for emulsification. When a suitable surfactant was added as a solution dissolved in the oily collector, a considerable increase in yield was observed.

Jan 1, 1993

By William E. Robinson

Our earthly treasures are being quickly depleted. We have experienced what can happen in an energy crisis. You have read and heard all kinds of stories as to what caused this crisis. On the surface it would seem that all of a sudden a situation becomes a crisis whether it be fuel, potatoes, beef or whatever. Well, of course, they don't just happen. There is always a little fore-warning here, an indicator there. Someone recognizes a sign of potential trouble but is ridiculed when he forecasts it. We are running out of sand: Producers of aggregates who can say today ... "That couldn't happen to me", can well be awakened tomorrow to the cold fact of reality. It could come from any number of directions. Depletion is mostly foreseeable but zoning isn't. Legislation can also be sudden death to availibility. With the ever growing population moving into the rural countryside, available deposits are being sold either to developers or being zoned for restricted use. The fact that a gravel pit or quarry is located on a particular plot has not fazed some of the local planning boards when they decided to place the adjoining property in a residential Zone A. Proponents of zoning preach that such use is necessary to insure that the land will be put to its best use. Planning boards establish the best places for schools, homes, shopping areas, factories, etc., so that the individuals or groups are in harmony with each other. This is usually done to date without thought or consideration to the geological importance or potential of the area. Today over half of the United States is living under some form of land use restriction. Little consideration has been given to what lies under the ground to be zoned. Fortunately, the states are slowly getting around to geological surveying. I feel that it is about time that state and federal authorities institute governmental restrictions to prohibit or control local zoning ordinances which would deplete or deny an area of its natural resources. While I could continue for the balance of my time just on this facet of our industry's problems, my point is: How sure are you of your next load of sand? I could be well laughed at by some of you for saying that there is an alarmingly rapid disappearance of "nearby" sand and gravel reserves in many areas of the country. A questionable statement, except to those producers where depletion has already taken place.

Jan 1, 1974

By F. Warnaars

Historically, this area produced gold and silver from many well-known vein deposits, like Tayoltita, Topia, and San Jose de Gracia. Modern exploration identified three categories of deposits: 1) low grade porphyry golds in shallow level dacite porphyries; 2) batholith-related deposits; and 3) those formed in volcanic sequences of Late Cretaceous to Late Tertiary. At least four porphyry golds have been identified, of which Metates is best known. These are formed by and within dacite porphyries, associated hydrothermal breccias and sometimes within surrounding metasediments. Their ages are from mid-Cretaceous to Early Tertiary. Precious metal deposits associated with batholiths occur as veins, contact haloes in metasediments or volcanics, skarns, tectonic breccias, hydrothermal tourmaline breccias, dacite dikes or as disseminated or stockwork deposits such as La Fortuna. Several new gold discoveries were made in older Early Tertiary Volcanic Sequences and in the younger Tertiary volcanics within prominent structures exceeding 3 to 5 km in lengths. Some of these are open-pittable but most have to be mined by underground methods.

Jan 1, 1999

By Hans von Michaelis

The renaissance in extractive metallurgical practices for gold and silver recovery is far from over. This is one conclusion of a three year investigation into innovations in Cold & Silver Recovery by Randol International Ltd. (1981, 1983). The six volume reference report reviews a host of new processes and innovative applications of older metallurgical practices. Some of these were summarized by von Michaelis (1982, 1982a). There are several reasons to expect this renaissance to continue. One reason is the nature of gold and silver deposits. The list of known occurrences of These metals is very extensive. There are literally tens of thousands of prospects but over 99% of these are too low grade, too small or too refractory for a viable operation employing conventional processing.

Jan 1, 1983

By Richard L. Patterson, Alan P. Finch

Twenty years ago, when tunnel projects in the UK were generally procured by the public sector, many were completed late and over budget. Now a significant proportion of new infrastructure is developed by the private sector. Seeking more certainty in cost and programme, promoters have tried new and radically different methods of procurement and contract forms. The paper will review these developments, then examine the approach adopted for some of the largest current UK tunnelling projects (both in the public and private sectors) including the Channel Tunnel Rail Link, the Heathrow Terminal 5 Development and new highway tunnels.

Jan 1, 2003