Search Documents

By Simon J. McDonald

In late 2007 Neptune Minerals Plc. commissioned Genesis - a leading consultancy and engineering company affiliated to the Technip group - to undertake a Seafloor Mining Conceptual Study for mining of Seafloor Massive Sulphides (?SMS?) in Neptune?s New Zealand licenses. A key deliverable of the study was information to de-risk the perception of SMS mining for investors the minerals, and that deep-sea mining of SMS material is technically feasible, commercially viable and can safely be managed as a sustainable marine resource industry. The aim of the study, completed in April 2008, was to evaluate alternative existing marine technologies for seafloor mining, ore lifting, dewatering and surface offtake, considering the following parameters: ? Efficiency; ? Reliability; ? Safety; ? Environmental impact; and ? Cost

Jan 1, 2008

By Panlop Huttagosol

The use of computer models to design ultimate pit limit of an open pit mine during its feasibility study has become an emphasized procedure in mining. It is a normal practice in open pit mine design to generate the most profitable final pit limit. The limitations of designing this optimal pit limit have been the requirement of significant computing efforts as well as the use of complicated operations research techniques. In an attempt to describe a computer method that has an easy conceptualization and is able to provide a precise and desirable solution, a new technique is developed. The ultimate pit limit problem is formulated as a large scale transportation problem. The formulation is based on the use of a three dimensional block model to represent an ore body and surrounding materials. The solution technique is developed through solving the dual system of the formulated problem by using the adapted simplex algorithm of linear programming. The implementation on given case studies demonstrates that the new method is capable of providing an optimum pit value. The computing effort required by the algorithm is still the main constraint in solving a large scale problem. The technique provides open pit mine planners with an alternative tool in using a commercial linear programming software which is capable of solving a general transportation problem. The selected software must be able to handle a large scale problem, and it needs an additional effort td formulate the problem and transform a result into the ultimate pit limit solution.

Jan 1, 1992

By Gustavo A. Aristizábal-H, Oscar J. Restrepo-B, J. Alejandro Delgado-J

"In Antioquia region of Colombia – South America most of extractive activity is developed as artisanal and small-scale level, exploiting different types of minerals resources but predominantly gold. This is not only an ancestral livelihood of hundreds of families in this region, but also their unique way of subsistence. However, that situation has not had a positive effect in the sustainable development of this territory because of several unsustainability factors mainly related to mercury use for gold extraction, the incorrect management of tailings and the informal way in which miners perform their activity. In 2010 Antioquia was the place with the highest contamination by mercury in the world with serious effects in ecosystems and health of habitants of this region (Veiga 2010) This paper presents a Socio-Technical Model focused on strengthening capabilities and social capital of artisanal and small-scale miners and its surrounding communities in Antioquia region. This is based on processes of evaluation, design and implementation of appropriate technologies to obtain “clean minerals” without using mercury and with a right management of tailings. In gold extraction it is about gravitational methods of concentration, which take advantage of high density of this element. These methods not only are cleaner but more profitable for miners. Notwithstanding its technical origins, the current model proposes a holistic framework that manages the elimination of mercury in mining not only as a technology transfer matter. Thus, more than formalization the strengthening process seeks to promote a business vision in miners and to develop productive chains in surrounding communities, this means to improve the skills of artisanal and small-scale miners to organize in a corporative way and to help surrounding communities to provide support and supply services to mining and even to other companies. Besides, the articulation with local institutions drives to reinforce their functions of control and accompaniment. In shorthand, this effort aims to empower local institutions, miners and surrounding communities in such a way they are able to face together their own development challenges in a sustainable way."

Jan 1, 2017

By John B. Goddard

The discovery of rhenium on the ion exchange resin used at the uranium in-situ leach operations at Palangana (Texas) led to a laboratory study on the possible methods of recovery. Rhenium, present in small amounts in the ammonium carbonate leach liquors as the perrhenate anion, Re04-, concentrated on the anion exchange resin, which was a factor of ten more selective for rhenium than for uranium. Various elution systems were investigated for stripping the rhenium from the columns after the uranium had been eluted with chloride or nitrate solutions. Although the perchlorate ion was most efficient on a molar basis, nitrate ion combined the benefits of efficiency and low cost. A 3[N] or stronger concentration of nitrate containing up to 0.5[N] H+ was found to be the system of choice. A rhenium sulfide concentrate containing up to 14% Re was obtained from these effluents by hydrogen sulfide precipitation. Preliminary experiments were run to produce rhenium metal powder by oxidation of the concentrate to NH4Re04 followed by hydrogen reduction at elevated temperature.

Jan 1, 1982

By Olivia Perkins, Shawn Sismondi, Adrian St. John, Vicky Potts

"INTRODUCTION An inherent aspect of any tunnelling project is ground risk: how it is identified, quantified and managed throughout the various stages of a project. Early identification of these risks, such as adverse ground conditions or potential obstructions is crucial; however specific identification of all risks will inevitably be limited by the extent of the desk study, ground investigation and accuracy of as-built information available, particularly in a densely populated urban environment such as London with a long and varied history of development. It is therefore crucial to have suitable plans and procedures in place for dealing with potential ground risk scenarios if they occur during construction work to ensure the safety of the workforce and to protect nearby critical assets. A number of experiences of potential ground risk were encountered during the Sprayed Concrete Lining (SCL) works on Crossrail contract C300/410 which was constructed by a joint venture of BAM Ferrovial Kier (BFK). The C300/410 works, undertaken in the heart of London, comprised of over 2.5km of SCL tunnels for Bond Street and Tottenham Court Road Stations and the Fisher Street crossover, as well as two 6.2km TBM tunnel drives between Royal Oak and Farringdon. BFK appointed Donaldson Associates as their SCL designers for the works; together they were responsible for excavation stability up to the point of ring closure. Despite the majority of SCL tunnelling works at Bond Street and Tottenham Court Road being through the favourable medium of London clay, there remained areas of local geotechnical challenges. Some of these were expected from the outset, some became apparent as works progressed from records of other nearby excavation works, and some were only encountered during tunnel excavation. Being located in the centre of London meant that there always remained a possibility of meeting some form of obstruction from previous structures. However, identification of all potential issues prior to the commencement of the works was challenging and proved to not be entirely possible. Through a series of case studies, this paper documents incidents where obstructions or adverse ground conditions arose. These scenarios all had the potential to cause safety risks, impact the tunnel design and/or construction methods and ultimately add time and cost to the works. The paper discusses how these challenges were overcome which utilised in part, a progressive risk reduction cycle, feeding back knowledge gained at all stages of construction into the approach for undertaking the works. It also examines what could be done in future to further reduce the ground risk through early identification, communication, education and appropriate contingency measures."

Jan 1, 2016

By W. M. Tupper

[The two types of sulfide deposits in the Bathhurst Newcastle area are; (a) epignetic fissure deposits, and (b) massive sulfide deposits. Geological evidence has been variously interpreted to suggest a syngenetic origin, a source bed' origin, or a magmatic hydrothermal origin for the massive sulfide deposits. Sulfides disseminated through the black shales and argillites of the host rocks are enriched in S32 (mean value 22.34, S34. = 5.8 per mil) relative to the meteoritic standard of 22.21, and have a broad spread in range of values. S32/S34 ratios of sulfide minerals from the deposits occur in two distinct groups. The massive sulfide deposits exhibit ratios between 21.88 to 22.05, while the fissure deposits exhibit ratios between 22.18 and 22.21. These results suggest two separate sources for the sulfur, each, however, resulting in magmatic hydrthermal deposition because of the narrow spread of ratios in each group. Granite intrusive into the host rocks of the sulfide deposits have a mean K/A age of 386 ± 10 M.Y. Lead minerals in the sulfide deposits have a mean nodel lead age of 370±20 M. Y. Thus the lead minerals and the granite bodies were emplaced during the same major orogenic event. Sulfide minerals from magmatic hydrothermal deposit have a very narrow range of S32/S34 values, as do those of the Bathurst area. It seems reasonable, therefore, that well homogenized magmatic hydrothermal solutions are the most logical source of the sulfide deposits. Furthermore, the homogeneity of the lead isotopic abundance data gives strong independent evidence that the ores are of a magmatic hydrothermal origin.]

Jan 1, 1960

By J. Bartrum

Semi-autogenous, (SAG), milling operations can realize substantial Increases in mill throughput by removing and crushing critical size, slow grinding, material from the SAG mill. Full-scale plant testwork showed that modifying the Kidston SAG/ball circuit to a semi-autogenous-ball milling-crushing (SABC) circuit would increase plant throughput by 25 to 30%. The methods used to determine the value of the SABC circuit and the design of the circuit are discussed.

Jan 1, 1988

By J. A. Herbst

Until the past decade, the energy-size reduction relationship was the dominant form of mathematical model used in the description of tumbling mill grinding processes (1,2). Typically, in these models some single measure of product fineness (e.g. the 80% passing size, the size modules, the specific surface area) is chosen as the dependent variable and the energy input per unit mass of material being ground acts as the independent variable. In some instances these models have been useful for the correlation of experimental data, but, invariably, they have been found to be inadequate for meaningful process simulation. During the last decade considerable advances have been made in the development of phenomenological grinding models derived from population balance considerations (3-7). In these models a set of dependent variables is employed, corresponding to the set of mass fractions which constitute the product size distribution, and energy input is abandoned in favor of "time in the mill" as the independent variable. The phenomenological models have been shown to provide accurate simulations of the entire size distribution of ground products produced in batch (8-10), locked cycle(11)and steady and unsteady state, open and closed circuit continuous grinding(12,13).

Jan 1, 1973

By P. Croney

Environmental monitoring requires major effort and expense but management of data receives less attention. A modem database system can manage hydrochemistry, water levels, meteorology, geology and downhole geophysics data and is flexible to allow the storage of ad hoc data. Reports can be customized by the user and derived data generated from input values. The production of high quality maps with contours and hydrochemical diagrams is an essential part of the reporting process. These maps integrate directly with the current site survey information. These facilities are best provided by storing the data in an industry standard database such as Oracle or Access to which customized AutoCAD and Microsoft Office routines make direct SQL calls.

Jan 1, 1997

By R. A. Hevia

Florida Power and Light is the fifth largest investor-owned electric utility in the country. It has a service territory that covers 35 counties, or 28,000 square miles, 2.5 million customers, and serves 5.6 million people. The total installed capacity is 13,470 MW, generated by four nuclear units, 36 oil and/or gas fired units, and 48 gas turbine units. Traditionally, FPL has been an oil-based utility. In 1979, this dependency on oil became obvious when 42 million barrels of oil were burned during the year. At that time, it was also projected that, based on the current estimates of customer growth and available generation capacity through 1990, FPL's residual fuel oil consumption would increase from the 1979 level of 42 million barrels (6.7 million m3) per year to approximately 55 million barrels (8.7 million m3) per year by the mid-1990's. Concern over this was further aggravated by the fact that it was difficult to estimate both the price and quantity of fuel oil that would be available over the next decade since changes in the world market, decisions by oil producers and refiners, and international political developments would all affect the availability of oil. Also, at that time, the price of residual fuel oil had increased drastically, and there was no reason to think that these prices would soon stabilize. Thus, oil back-out became a primary objective of FPL and since then, FPL has been actively investigating ways to decrease fuel oil consumption.

Jan 1, 1985

An atomic force microscopy (AFM) has been applied to study the adsorption of potassium amyl xanthate (PAX) and potassium ethyl xanthate (KEX) on arsenopyrite surface in solutions. AFM images show that the collectors adsorb on arsenopyrite surface in patches at pH 6. Increasing the chemical dosage will increase the adsorption density of the patches on mineral surface. The increased probe-arsenopyrite adhesion measured in PAX solutions at pH 6 is attributed to the adsorption of the patches, suggesting the hydrophobic nature of the patches, which is likely the oily dixanthogen. It is also found that arsenopyrite is reactive in water in the presence of air. At a high pH with the addition of Ca(OH)2 the adsorption of collectors on arsenopyrite is greatly retarded or depressed because the mineral surface is coated by a lot of precipitates, which is hydrophilic in nature as shown by the measured strong repulsive probe-arsenopyrite detachment force. The findings confirm that the flotation behavior of arsenopyrite in xanthate solutions is very similar to that of pyrite.

Feb 27, 2013

By V 9. 0 / 300 dpi

In the time period from the early 1980's to the present, longwall roof support technology has evolved tremendously. Chock supports and caliper shields were replaced by 2-leg or 4-leg lemniscate shields. The lemniscate linkage for which the support is named offers numerous advantages to the sup-port both as a fabricated structure and to its performance in the mining application. The hydraulic system, which is the dynamic element of the roof support, was essentially unchanged in early lemniscate shields with the exception of the complexity of additional hydraulic circuits to power a canopy tilt cylinder and canopy side-seals. The control of these fluid-powered functions was provided by direct manual control of valves energizing individual functions onboard the roof-support or the adjacent roof-support. This control valve-gear was comprised of multiple individual valves arranged in a "bank" or integrated into a single hydraulic distribution block with a single operating handle to select any independent function.

Jan 1, 1993

By T. Braun

A greenfield open pit gold mine in Latin America suspended operations less than three years into an eight-year mine plan after a waste rock dump and heap leach facility sustained substantial damage from a deep-seated landslide. No injuries to employees were recorded because of the slow-moving failure. Due to early detection by the operations team, the owner had sufficient notice of the potential failure and successfully rinsed the heap leach facility prior to the failure event. Engineers estimated approximately 35 million cubic meters of mass movement below the waste rock and heap leach facilities. The original eight-year mine plan produced approximately 60,000 ounces of gold per year. After the failure, the owner terminated gold production, re-configured the mine site to a safe, standby condition and launched a detailed investigation into the root-cause of the failure. Approximately two years after the shutdown, legal interests filed a statement of claim and named three engineering design firms and individuals involved in the project. Several years of litigation, including discovery and deposition proceedings, followed as the legal process considered evidence spanning a 20-year timeline. Changes in project ownership and consulting firms during the development and operations phase complicated the process. In 2017, the plaintiff and last defendant settled. The author was involved as the corporate representative for one of the engineering design firms.

Mar 2, 2022

By Barrie W. Sullivan

The New Celebration Gold Mine near Kalgoorlie in Western Australia was commissioned in late 1986 and the CIL treatment plant currently processes 1.7 million tonnes of gold ore annually. The 1988 geological resource was 13.2 million tonnes grading 2.37 g/t Au in several open pittable deposits with the bulk of gold mineralisation occurring as a stockwork in Archaean quartz feldspar porphyry intrusives along a major regional shear zone. Mine planning, scheduling and operating techniques have focused on minimising open pit dilution whilst maintaining production requirements. This paper describes the successful achievement of this aim in extremely variable ground conditions and orebody widths.

Jan 1, 1989

By Moussa Wone, Martino Scialpi, Colin LaVassar, Carlton Ray

The Potomac River Tunnel (PRT) is the next major phase of the DC Clean Rivers Program. The design-build PRT project includes a 5.5-mile-long, 18-foot-internaldiameter tunnel, seven shafts, and two underground connections to existing structures. Major challenges include tunnel boring machine (TBM) excavation though mixed-face conditions within a buried paleo-channel and an approximately 1,350-foot-long rock/ soil transition zone; construction beneath the elevated Whitehurst Freeway; tunneling beneath an existing luxury residential building and existing transit tunnels with limited clearance; and complex coordination with a variety of federal, regional, and local stakeholders. This paper describes the overall project scope, geotechnical conditions along the alignment, and primary design/construction challenges and mitigations.

Jun 13, 2021

By N. Del Bel Belluz

Drilling underground in the Grasberg De-watering drifts has routinely hit water aquifers with high flow rates and pressures. Two types of holes are utilized; pilot-holes to probe ahead of the tunnel development to intersect aquifers ahead of the face; and de-watering holes to de-water rock formations that will drain water from the Grasberg pit and allow tunnel development to proceed safely. Recently, rates of 1050 psi static pressure have been recorded with flows from a NQ hole measured at 1350 gpm (US). The water flows can be slightly acidic, necessitating the use of stainless steel collar gear to resist corrosion. These rates were anticipated and contingencies were planned early to deal with these conditions. The collar gear is used to control water flows whereby the water is treated as an important resource. As a result, pm has established procedures to maintain safety of the drill crews, enable coring of the rock and to maintain safety of the miners who are driving the drifts.

Jan 1, 1998

By Michael W. Glasson, Archie M. Richardson, Leo Gilbride, Laine Adair

Andalex Resources, Inc. recently engaged in a ventilation planning exercise that resulted in the construction of a new main fan installation to support longwall coal mining at the Aberdeen Mine. This paper documents the planning process, including underground measurements, modeling, permitting, and construction of the new fan installation.

Jan 1, 1997

By A. Bruynesteyn

Results are presented from a series of tests designed to determine the beneficial effects of the microorganism Thiobacillus ferrooxidans upon the leaching of uranium from a pyritic uranium ore. Minus 1-inch (-25mm) 0.0711 percent uranium containing, pyritic ore from the Rio Algom Mine at Elliott Lake, Canada was leached with lixiviants of various Eh and pH as well as being subjected to a biologically-assisted ferric iron leach. In all cases, the biological leach gave superior extraction. At pH 1.6, the biological leach gave 100.6 percent extraction and the ferric iron leach 69.8 percent. This improvement in extraction is associated with a relatively rapid biological breakdown of the pyritic material, thus liberating uranium mineralization associated with these pyritic materials and regenerating the ferric sulphate lixiviant in situ.

Jan 1, 1981

By Jerry M. Whiting

Greater awareness of the increasing need to develop supplementary energy sources is accelerating us towards many basic decisions regarding future utilization of mined energy materials -- uranium, coal, oil sands and oil shale. The latter material comprises a major potential source of oil which will require creation of unusually large and low-cost underground mining systems. In this paper, the author briefly outlines and analyzes several of the factors which continue to provide the somewhat unique character of oil shale nine planning and mine operation.

Jan 1, 1974

By P. M. Soupios

A near geophysical surface investigation of a landfill area close to the Hania city, in Crete Island, Greece, was conducted as inextricable phase of a preliminary geotechnical, geological and hydrogeological study of the area under investigation. Electrical Resistivity Tomography (ERT), one of the most promising prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied for the geophysical modelling. ERT is a robust imaging method the theory and implementation of which are well documented in geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7km east of Hania city in Crete I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also identified at various scales which are recent tectono-karstic voids resulted from the combined actions of karstic erosion and tectonic stress on the Trypalion limestones where they are located. Due to the above-mentioned geological singularity and in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out by deploying the dipole?dipole electrode configuration. Specifically, seven geoelectrical tomographies were conducted reaching the prospecting depth of 36m. The resulted images conduced, a) to overcome geotechnical problems, b) to plan the future sites for waste disposal and c) to reliably estimate the thickness of the already deposited wastes.

Jan 1, 2005