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By George S. Barnett

The Equis and El Roble projects are located in the Cordillera Occidental of Colombia. The Equis vein deposits have sulfide ore reserves of 95.9.5.5 mt (105.770 st) grading 8.51 g/mt (0.248 oz/st) gold and 12.4 g/ml (0.36 oz/st) silver with 0.94 % copper. 1.10 a lead and 11.06% zinc. Ore reserves at El Roble are estimated as 1.1% Mmt (1.21 million st) grading 4.89% copper and 3.39 g/mt (0.099 oz/st) ,old. Geologically possible reserves at Equis may total 1.6.Mmt (1.76 million it). El Roble has the potential to contain several tens of millions of metric tons. Exploration included diamond drilling, trenching, channel sampling, rock and soil geochemistry, geophysics and tunneling. Erratic high grade samples affect the weighting of channel and drill core samples. Secondary reconcentration of gold is also a factor. Sample maps and graphs show the distribution of values to be highly variable. Geostatistical treatment of some of these data gave important guidelines for parameters such as sampling densities, drill hole spacing and confidence limits.

Jan 1, 1984

By Yosry A. Attia

One of the most significant advances in Mineral Processing in recent years, is the development of the selective flocculation technology. The technology is primarily aimed at recovering the mineral values from ultrafine ore suspensions. This is achieved by selectively aggregating the mineral particles in question to such size as to enable their effective separation from the suspension. Selective flocculation utilizes the differences in the physical-chemical properties of the various mineral components in the mixed suspension. It is based on the preferential ad- sorption of an organic flocculant on the particular solids to be flocculated, leaving the remainder of the particles in suspension. In order to understand the mechanics of this process, selective flocculation may be divided into four major sub processes; these being: ore slurry dispersion, in which all the particles are stably and uniformly distributed in the suspension with the individual particles being essentially separate; flocculant selective adsorption and floc formation; floc conditioning, which aims at obtaining flocs with desire properties for their subsequent separation and with minimum entrapment of dispersed particles; and floc separation from the suspension. These sub processes will be reviewed later in this article.

Jan 1, 1982

By B. M. Davis

The problem of assessing uncertainty in grade estimates has been a topic of research and debate since kriging was first introduced. Use of the kriging variance was originally touted as all that was necessary in order to produce confidence limits for grade estimates. Since then the prudence of using the kriging variance for confidence interval estimation has been questioned, and techniques such as the jackknife and conditional simulation have been proposed to develop "true" interval estimates. This paper compares the differences between interval estimates produced by the three methods and makes conclusions about the performance of confidence intervals produced by the different methods.

Jan 1, 1997

By G. J. S. Govett

Dwindling near-surface mineral reserves emphasize the need for the development of exploration techniques capable of greater depth penetration; geochemical techniques tradition- ally have been restricted to the search for deposits having at least a sub-outcrop expression. Rock geochemical techniques developed in Cyprus in 1967-1968 recognized anomalous conditions in volcanic rocks up to one mile from an ore de- posit. Research by the Exploration Geochemistry Group at the University of New Brunswick has shown that some massive sulphide deposits in New Brunswick have well-defined halos of major, minor, and trace elements in the host rocks extending up to 1,200 metres (4,000 feet) laterally along the same stratigraphic horizon, and up to 450 metres (1,500 feet) vertically in hanging wall rocks which apparently post-date mineralization; well-defined halos have also been found in foot- wall rocks. Some of these halos are readily identified as individual elements or as element pairs; others are so subtle as to be recognizable only through computer-calculated multivariate analysis. Research continues to extend the dimension of rock geochemical halos for regional exploration and for identification of more restrictive anomalous conditions which may closely define the location and extent of buried sulphide deposits.

Jan 1, 1975

By W. V. Swarzenski

In its, effort to combat waterlogging and coil salinity, the later and Soils Investigation Division of WAPDA (West Pakistan's Water and Power Development Authority) has carried out an extensive program of test drilling and water sampling, since 1954. Data collected during the past ten years have permitted the delineation of fresh and saline ground-water-zones in the Punjab Plain. Fresh ground water containing generally, less than 500 ppm (parts per million) of total dissolved solids is found in wide belts paralleling the major rivers and in other areas of fresh-water recharge. Locally, fresh ground water extends to depths of 1,500 feet and more. Saline ground water occurs downgradient from sources of recharge, particularly in the lower central parts of the interfluvial areas and, presumably, underlies most of the Punjab Plain. The ground waters of the Punjab are characterized by their evolution from calcium, magnesium bicarbonate waters, near sources of recharge, to waters containing a dominant proportion of sodium. The highly mineralized waters of the Punjab are generally of the sodium chloride type, whereas in Dera Ismail Khan District sodium sulfate waters predominate. The pattern of distribution of saline ground-water zones and the observed gradual increase in mineral content, downgradient from sources of recharge, can be explained best by a hypothesis stressing the processes of evaporation from the water table and solution of minerals within the alluvial aquifer.

Jan 1, 1967

By Drew Bazil, David Smith, Matteo Ferrucci, David Pittman

The Gateway program will provide additional rail capacity between New Jersey and Manhattan. This paper describes how a 70-foot-deep section of cut and cover tunnel was designed to directly support future high-rise towers. The tunnel will link previously completed tunnel sections under Hudson Yards to future tunnels under the Hudson River. The design aims to minimize constraints on future overbuild and future tunnels, while maximizing constructability within a small worksite. The tunnel will pass under the High Line elevated walkway, next to an active rail yard, and close to a subway tunnel. The design was developed by a tri-venture of WSP, STV and AECOM. WSP led the design of major underground works; STV designed utility relocations and the underpinning concept for the High Line; and AECOM designed temporary in-tunnel systems. Construction is expected to start in 2023.

Jun 13, 2023

By George Schmitt, Ted Dowey, Grant Millener, Sean McAndrew, Eric Jordan

The Rondout-West Branch Bypass Tunnel is being built to bypass a substantial leak in New York City’s primary water supply tunnel. The 13,500 foot long tunnel travels 600 feet under the Hudson River through the same troubled geology and high pressure water inflows that the original tunnel did in the 1940s. A Robbins TBM traversed this geology and built gasketed segments. Nine thousand two hundred feet of 16 foot diameter interliner was installed and backfilled within the segments. Finally, reinforced cast in place lining was placed. This paper addresses the challenges and the multi-tasking approach the contractor utilized.

Jun 13, 2021

By R. Berton, M. Walden, S. Melberg, N. Rocco

Recent tailings dam failures around the globe have influenced many mining industry regulators to reassess their requirements for the numerical modelling of tailings dam failures. This type or forward modelling is associated with overarching uncertainties as the model cannot be calibrated against a physical result. Dam breach analyses that meet the requirements of current industry standards and guidance typically begin with identification of credible failure modes and selection of appropriate topographic data set to represent the study area. The breach parameters and the volume of tailings released are then determined using available methodologies and empirical relationships. Subsequently, when the breach hydrograph is developed and the hydrology of stream networks are complete, the runout simulation is implemented. Due to the uncertainty involved in the process, sensitivity analyses are recommended to quantify variations in model inputs on the inundation extent and the flow characteristics. This paper outlines some common methodologies utilized for development of dam breach models, summarizes associated uncertainties with these methodologies and inputs, and provides guidance on how sensitivity analyses can address a wide array of uncertainties inherent in tailings breach analyses. This paper provides an understanding of how selecting appropriate breach parameters can result in reasonably conservative inundation extents consistent with the identified credible failure modes.

Mar 2, 2022

By B. Ballard

Engineers at a West Virginia coal preparation plant owned by one of the nation's largest coal producers sought a fire suppression system for the plant's MCC and cable spreading rooms. Officials considered the traditional options of water-based sprinklers, dry chemical, and clean agent systems; however, each of those options presented challenges. Sprinklers can damage electrical equipment, proper delivery of the agent and adequate coverage/protection can be an issue with dry chemical systems, and clean agent systems require room integrity. An alternative to traditional systems was discovered in the Victaulic Vortex Fire Suppression System. The first hybrid inert gas/water mist system (FM 5580), Vortex adequately addressed these concerns. The system, which deploys a high-velocity, low-pressure mixture of water and nitrogen, is not damaging to electrical equipment and extinguishes fires in open, ventilated areas. This is one of the first installations of the Vortex system in a prep plant, and is a compelling example of how new technology can overcome the challenges of traditional technologies. The paper will detail plant specs, situation, and system evaluation, selection, and configuration.

Feb 23, 2014

By M. A. Qianjie

The problems of coalmine safety in china remain unsolved for decades. Starting with the description on safety status quo of coalmine in china, different existing analysis and measures discussed for the safety problem solution of coalmine china. With the consideration of system thought in mind, the author present with a unique systematic reason analysis method on such actuality--individual analysis and general analysis--each for its particular purpose. Upon such cause analysis, construction of the safety system is made clear and, solutions for such problems provided.

Jan 1, 2006

By L. C. de Kooker, K. Esmaeili, I. Musonda, M. Ferentinou

A numerical investigation of the effect of pore pressure regime on the safety factor and the critical failure mechanism is presented for fly ash storage facility. Pore pressures’ measurements from standpipe piezometers and pore pressure estimated from seepage analysis are used to compare the factor of safety for a fly ash slope. This was applied for considering static and seismic scenarios. A probabilistic approach was applied to account for the uncertainties resulting from the limited data available and support a qualitative risk assessment evaluation. Slope stability analysis is conducted in two and three dimensions, adopting the limit equilibrium analysis approach, and also a finite element seepage analysis, to assess the stability of the slope. The two-dimensional cross-sections were extruded to three-dimensional models to estimate the factor of safety and associated shear failure. The results from the performed analysis suggest an increase in safety factor values of 5%.

Mar 27, 2024

By C. Pitzer

"Safety performance in many companies and even industries has stalled in the last decade. Accidents rates are at a “plateau” and yet, serious accidents and fatality rates are not. In more dramatic cases, such as in the BP Texas Refinery disaster, organizations that have “exemplary” safety statistics, suddenly have a catastrophic or multi-fatality event occurring. Classic examples are the Piper Alpha disaster and NASA’s Challenger and Columbia disasters, the BP’s Deepwater Horizon Rig disaster in the Gulf of Mexico. Looking into the causes of these accidents provides an insight into the events and deficiencies that led up to the accident, but what are the common features in the organization’s mindset, or its culture? What characterizes these organizations’ decision-making, their approach to safety and to risk and are there features that can be delineated? The research and review presented in this paper covers a period since1995, which started in the Australian resource industry and since then covered international events. The features of these organizations are summarized as the seven deadly delusions of near zero organizations (NZO) that suffered unexpected disasters, based on extensive research by the author. More recently, the massive West Fertilizer plant explosion in Texas, and the Train Disaster in Lac-Mégantic, Quebec, Canada underlined the same trends. Organizations may experience calamities not because they are bad, or unsafe, but because they have become “cult-like”. INTRODUCTION The train disaster of 6 July 2013, in the small town of Lac-Mégantic in Quebec, Canada, in which 47 people were killed, had many strange pre-cursorsso-called “black swan” events that have occurred in many different industries. Black swan events are so rare, that there is almost zero chance that they will ever occur again, but they are so calamitous that the responses to these are emotional and irrational, (but necessary) and in those responses, the seeds for other, different black swan events are put into place. It is not what we don’t do, or do wrong, that causes modern disasters, it is what we do. The same things in the culture that make us successful, may also cause the disasters. We slowly, incrementally and insidiously ‘float’ into disaster. One such Black Swan event: The Piper Alpha Oil Rig disaster, killing 167 men in the North Sea on the 6 September 1988, was one of the most pivotal events in safety around the world. It changed the thinking and focus of governments, whole industries and led to numerous books and papers. It resulted in new legislation, textbooks and a critical self-examination by the oil and gas industry."

Jan 1, 2016

By P. M. Pettit

Hydrologic investigations at Gold Quarry began in 1989 and continued through 1991. Hydro-stratigraphic units include Tertiary sedimentary rocks, Paleozoic siltstones and carbonates. These units display complex and variable aquifer parameters as a function of faulting and hydrothermal alteration, creating compartmentalized hydrologic domains. Testing has included step-tests, spinner production logs and constant discharge tests. Two Three-Dimensional Finite Element Models have been developed, one for optimizing the pit dewatering system and the second for predicting regional impacts of dewatering. Aquifer testing and long term pumping have been used to calibrate both Finite Element Models.

Jan 1, 1992

By William A. Riggs

Salt, a non-metallic mineral whose use dates back to earliest history of mankind, and whose uses cover the widest range for any mineral raw material, is generally of widespread occurrence in commercially recoverable quantities in the oceans, in certain sedimentary rocks, in certain lakes, and in certain underground waters. Passing over geological detail, it may be said that, generally, all of the salt in the world has, at least once in geological history, been in solution in the oceans. The total salt content of today's oceans, said to equal 4.5 million cubic miles of rock salt, dwarfs the tremendous volume of salt in the sedimentary rocks. In 1958, United States production of salt was about 22 million net tons and world production about 82 million. About 3 percent of United States production is table salt, with chemical, municipal, industrial and agricultural uses taking the remainder. Mississippi River. Figure 1 has been expanded sufficiently to show also those salt occurrences and producing points which might economically ship salt into these states. Although widespread in occurrence, salt deposits and possible production areas generally show very sharp local boundaries. Salt-for non-table use is susceptible to ?place value?, a common problem in low valued raw materials, where transportation costs often exceed the value of the material f.o.b. the production point. Generally only large capacity mechanized salt producing operations can compete in United States markets, as contrasted to the many small local salt evaporators in less industrialized Mexico.

Jan 1, 1962

By George C. Toland

Most existing impoundment ponds and dams leak effluent into the soil or rock upon which they are constructed. However, proposed environmental legislation will require very stringent control on the release of toxic effluents such as cyanide. More exacting investigation, design, and construction techniques than have been used in the past will be required to satisfy these new regulations. This paper discusses the types of field and laboratory investigations required to develop the data for the design of an impoundment system containing toxic effluent, and discusses in detail technical considerations necessary to design this system. Design topics include reservoir sealing with natural and man-made materials; embankment sealing; embankment design considering stability, surface hydrology, capacity, and downstream catchment basins; and special implications of cyanide effluents.

Jan 1, 1975

By D. S. Davies

Further development of the Nitric-Sulfuric Leach (NSL) process has led to an improved design of the leach and nitric acid recovery steps. NO produced in the leach step is reacted with oxygen, regenerating N02, which is sparged directly into the leach reactor. Leaching is simplified to two steps and the nitric acid plant is replaced with an oxidation recycle gas sys-tem. Laboratory work substantiated the concept and led to selection of operating conditions. The lab work also pointed to improved process control compared to use of nitric acid as the sole oxidant. Recovery of copper from purified pregnant liquor is modified to use air agitation electrowinning improving cathode quality and lowering tankhouse costs. Economic evaluation shows reduction of capital requirements from $2400/AT to $2000/AT in 1978 dollars for 50,000 TPY of copper production.

Jan 1, 1978

By Rosario Lunar, Jesús Martínez-Frías, Egidio Marino, Trinidad Torres, Jose E. Ortiz, Juan A. Martín-Rubí, Luis Somoza, Ricardo León, Teresa Medialdea, Javier González

Seamounts, submarine banks, volcanoes and undercurrent channels are prominent geomorphic features that have become an important target for minerals research and exploration with the goal of future exploitation. Polymetallic ferromanganese deposits are common types of mineralization on these settings. Co-rich ferromanganese crusts are important as potential resources of Mn and Co, but also Ti, Ni, Tl, REEs, PGEs, and other metals. Many seamounts and channels along the Atlantic Spanish continental margin are known to hold mineral deposits but are poorly studied. This work presents and briefly describes the most recent activities of the Spanish Geological Survey (IGME) on exploration and investigation of ferromanganese deposits along the Atlantic Spanish continental margin. Different submarine areas from the northwestern margin of the Iberian Peninsula to the west off Canary Islands have been surveyed by geophysical, sampling and underwater observations from 89 to 4000 m water depth. The mineral deposits cover a large diversity of submarine geological and geomorphical features: mud volcanoes and diapirs related to hydrocarbon seeps, seamounts associated with hot spot volcanism, hydrothermal vents in active magmatic volcanoes, structural basement highs and banks or contourite channels. Considering the collected dataset, we present the preliminary results of the study of these mineral deposits, including ferromanganese nodules and crusts and phosphate pavements and nodules, which can be considered as potential sources of raw materials.

Sep 1, 2014

By J. B. Hiskey

The principle oxide minerals of molybdenum are wulfenite (PbMoO4), ferrimolybdite (Fe2(MOO 4)3.nH2O), powellite (CaMoO4), and ilsemannite (Mo304). Wulfenite is found in Arizona, New Mexico, Nevada, Utah, California, and Montana. It is also found in the states of Sonora and Chihuahua, Mexico. Prior to 1915 wulfenite ores were the primary source of molybdenum. The solubility of wulfenite in hot sodium sulfide was first noted by Bonardi(1) during attempts to sulfidize wulfenite material prior to flotation. He identified lead sulfide and soluble sodium molybdate as reaction products. Bacon (2) sulfidized wulfenite in preparation for flotation and by X-ray analysis found the reaction product to be lead sulfide. Holmes(3) made an extensive investigation of the extraction of molybdenum from wulfenite concentrates by leaching. Nearly 100% molybdenum extraction was possible from -100 mesh samples leached for 15 min with 10% sodium sulfide solution at room temperature. Molybdenum extraction from -100 mesh samples after leaching 30 min at a temperature of 45°C using 2, 4, and 6% sodium sulfide was about 32, 79, and 98% respectively. The extraction showed little sensitivity to time, temperature, or particle size using 10" sodium sulfide solution.

Jan 1, 1976

By S. D. Michaelson

Open pits and quarries are the major sources of all "hard rock" tonnage mined today. Normally, ore is fractured from the pit face by blasting and then truck-hauled to a primary crusher where processing begins; over- burden (or waste) is generally truck-hauled from the pit to dump areas. Truck haulage of blasted ore and overburden accounts for some 25 to 50 percent of total mining costs in a typical open pit and commonly is the largest single cost factor. Obviously then, cost reduction efforts should properly focus on improving existing haulage systems and developing new breakthrough techniques for material transport. Continuous flow systems for large tonnages ordinarily will result in a lower cost than batch systems such as truck or rail haulage. Continuous flow with pipelines for liquids and slurries, or conveyors for medium to coarse dry materials (in the -8 in. range) are the accepted economic answers for bulk materials handling over reasonable distances.

Jan 1, 1968

By J. Weinstein

New erosion, corrosion resistant metal, ceramic, and polymer composite technologies are being developed and marketed by Alanx Products L.P. for use in hydrocyclones, pumps, valves, and other applications in mining and minerals processing. This paper will present an overview of the ceramic/metal composite material system and properties developed, which include excellent erosion/ corrosion resistance. Wear data will be shown from a variety of laboratory tests in dry and wet conditions, in aqueous neutral and corrosive environments. Comparisons will be made with a variety of competitive materials currently used in the industries sited. Data will also be presented on field tests with pumps and hydrocyclones in hard rock mining and other abrasive/corrosive environments. Field data from North and South America, as well as Australian mining applications will be highlighted.

Jan 1, 1992