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By R. Hogg

Experimental studies of the axial distribution of particles along dry ball mills are described. The results, for mills ranging in diameter from about 10 cm to 1 meter and operated in both the batch and continuous modes, indicate a consistent pattern of significant migration of particles away from the ends of the mill. In some, but less frequent, cases axial migration of the grinding media is also observed. Analysis of the data suggests that particle migration results from end-effects which extend for a distance of about one mill diameter along its length. End-wall roughness appears to play a significant role in the particle migration phenomenon. Media migration is generally associated with continuous mills operating at relatively high powder flow rates.

Jan 1, 1994

By Kenneth R. Ware

I INTRODUCTION The Washington Metropolitan Area Transit Authorities (WMATA) rapid transit system (METRO), currently under construction, will have a total length of 98 miles. Forty-eight of these miles are underground and require either open cut excavations or tunnels. Despite stringent construction controls, it is inevitable that some ground settlement will occur adjacent to the deep open cut earth excavations and large diameter earth tunnels. It is therefore essential to underpin nearby important structures to prevent excessive differential settlements and Fig. 1 presents the METRO criteria for this underpinning. This paper describes the underpinning methods currently used on METRO and evaluates the effectiveness of each method. II DESCRIPTION OF SUBSURFACE STRATA The foundation materials in the Washington, D.C. area are extremely variable. Fig. 2 presents an idealized profile showing typical subsurface strata. The engineering properties of each stratum have been determined by extensive exploration and testing programs. Fill: Washington, D.C. fills consist of every variety of soil and rubble. They are not important to this study because no underpinning is founded on fill material. Terrace Deposits: Formed in outwash plains during the glacier period, these deposits are composed of random layers of either sand 1 The writings and opinions expressed herein are solely those of the author and do not necessarily reflect those of WMATA.

Jan 1, 1974

By G. W. Poling

Chemical and physical properties of thiol collectors are reexamined to compare the prospects of heavy metal-thiolate or disulphide surface reaction products acting as actual collector species. Recent evidences for the existence and importance of each of these types of adsorbed species on sulphide minerals are also discussed. A conclusion is reached that partial coverage by chemisorbed heavy metal thiolate is often sufficient to confer practical levels of hydrophobicity and floatability. Only on a few highly conducting and "noble" sulphides does adsorbed disulphide-type collector oxidation product appear to be significant.

Jan 1, 1976

By S. C. O?Brien

This paper develops the procedure for simulating the special locked-cycle Work Index laboratory test using the kinetic parameters obtained by conducting standard size-mass balance (SMB) grinding tests and presents the results for three materials - quartz, a taconite iron ore and a bituminous coal. It was found that the WI could be determined by simulation; however, if a material breaks abnormally, a full description of its abnormal breakage is necessary. It was also found that the sensitivity of the WI test procedure to the sieving process and the estimating of the 80% passing size of the sieve undersize is sufficient to question the practice of quoting a WI to two or more decimal places. Finally, if a material grinds abnormally in the Work Index mill, then the WI test should not be conducted.

Jan 1, 1987

By Steven A. Moreno

Geochemical returns from commercial analytical laboratories are often delayed because of postal and other bulk distribution inefficiencies. Consequently, minerals exploration programs are handicapped due to insufficient time for treatment, analysis, and diagnosis of the data. The minerals industry lacks a system for rapid transmission of geochemical data which allows immediate entry into statistical and plotting routines. Over the past three years, Houston International Minerals Corporation (HIMCO) has developed a computer-based system to receive, treat, and distribute geochemical data. In the past two years, Bondar-Clegg (Denver) and Chemex (Vancouver) have developed systems to transmit' data directly to HIMCO via the world-wide Boeing Computer Services (BCS) network. The main benefits to HIMCO have been ten less days for reporting turnaround, ten less days for keypunching, less data handling, accuracy. The benefits to the laboratories have been improved in-house data management, reporting, and HIMCO's increased geochemical activity.

Jan 1, 1982

By D. W. Hill

By seeking to define the social and political parameters of both established and potential uses of the underground, this paper will attempt to formulate and state the problem posed in the realms of public choice for obtaining more rapid development and more beneficial use of the underground environments. Essentially, the paper will pursue the following outline: 1. Established policies and established uses of the underground 2. Potential uses of the underground for social benefit 3. Constraints on development and policy a. Psychological constraints b. R & D plus physical constraints c. Economic constraints d. Public choice and policy contraints (both governmental and non-governmental) e. Legal and other structural constraints 4. Defining the problem from the social standpoint 5. Suggestions for surmounting the constraints and meeting the problem: some hypotheses for the future.

Jan 1, 1974

By Vladimir J. Ovdenko, Sergey N. Lazarenko, Evgeny L. Schastlivtsev

The term sustainable development shortly appeared in international use in the run of UNO Environmental Protection Conference held in Rio de Janeim in 1992, bears the concept, that evolution process ( associated either with a region or society) should provide mutual interests concern in three aspects - environmental, economic and social ones, admitting as well the fact , that environmental protection should become an integral part of each process and cannot be regarded separately. In this connection it seems quite reasonable to employ the principal of sustainable development, while creating the model of industrial mastering the territory constraint lands viewing their future, for a example, in rich mineral deposit's development. In Kuznetsk coal basin in Russia ( west Siberia) the development of a big coal deposit Erunakovsky is now being underway. The major part of coal will be mined with open cast method, resulting the number of local environmental adverse impacts' occurrence. In such a situation mastering of sustainable development model is given the top priority, demonstrating the essential result of its application in a form of possibility to define the best correlation between economically expedient and environmentally tolerable loads during coal mining. The given paper is an attempt to work out the main principals to approach the creation of sustainable development model in regard of the definite region case. To simplify the presentation of employed approach's main idea, the given below accepts as its component only one of many actually existing environmental profiles, that define mining pro- cess impact on environmental situation -the size of infringed (de- graded) lithosphere surface. Basically, the actually existed correlation between spheres. grounding the model of sustainable development - economic, environmental and social- is given in a form of nomogram under Fig.1. On the presented graph the prognostic values of broken lands relative extent within Erunakovsky boundary ( to be compared with total region area taken as 100%) are arranged on axis x". Axis "y- demonstrates the main values associated with complete economic background, making the intrinsic part of the principal for sustainable development, i.e. annual coal output for the given area. It's top, used in assessment value relates to actual showings implied for the study region project and quantifies 60 min. tons. While regarding the social facet of principal for sustainable development, the applied mode to separate social issues into two types - one profiling a welfare standard of living and the other. pertaining the way environmental situation contributes to the degree of &ologica-1 comfort in people's living was defined as the most expedient and the most adequate in the matter of reflecting the actual terms of vital activity of the society. In accordance with the cited above the economic level showings are plotted on the graph on "-x” axis, while "-y" one obtains the values associated with the point of ecological comfort presented in conventional units. For the maximum possible conventional point of living (corresponding in nomogram to 1.0 value) a welfare level secured with industrial region economic activity revenue was assumed in case the top planned annual amount of coal is delivered ( 60 min. tons). While studying the index of public economic welfare, environmental conditions corresponding level in its original state i.e. prior to any industrial work carried in the region, was adopted as its top possible conventional rating (1.0). The given nomogram displays the integrity of x-f(y) type interrelations plotted on the basis of four separate dependencies, precisely a) the size (area) of infringed earth's surface as a function of coal output in the region; b) subordination of ecological comfort of people's living to the degree of lands infringement; c) interconnection of economic and environmental components of people living; d) interconnection of economic level of people's living and the amount of coal mined in the region. Linked to a single unit, these separate plain dependencies create, as seen from the graph, a more intricate system of bonds, that affords during defining or changing this or that system parameter to secure undergoing changes, that occur to other parameters of the system. The mentioned reason made it possible to consider and drive to mutual conformity ( as far as it is possible) all parameters values for the defined system's relations, that in their turn indicate the concern of other aspects of a sustainable development principal. According to the graph, in order to get not more than 50% of infringed land left after the deposit's mining, it is advisable to ex- tract not more than 40 min. tons of coal annually, gaining in this case the level of ecological comfort for living in the amount of not

Jan 1, 1996

By D. M. Neil

Road-headers are one of the most popular mechanized excavators used in mining and civil under-ground construction. These machines are primarily used in soft to medium hard rocks. This paper reviews the parameters associated with the application and operation of road-headers and presents a method for estimating cutting performance.

Jan 1, 1994

By Thomas D. Henderson, Wayne R. Hopkins, Arthur Lynch

Brought on stream in 1975, the 10,000-tpd copper oxide processing plant of Anamax Mining Co. at Twin Buttes, Ariz., is now at design capacity. Based on acid agitation leaching, solvent ion exchange, and electrowinning, the Anamax plant bridges an ore to metal gap by producing mine site copper cathodes from lime-bearing oxidized feed. Until recently, such material was considered submarginal because copper recovery was uneconomic using conventional methods. The new Twin Buttes oxide plant, the largest of its kind in North America, is one stage in the expansion of Anamax, a joint venture owned equally by The Anaconda Co. and Amax Inc. Other phases include an accelerated stripping program in the pit, an expansion of the sulfide concentrator from 32,000 to 40,000 tpd, and construction of a 57 MW diesel generating station for the oxide plant. Once the basic oxide flowsheet had been selected, Anamax awarded a contract to a joint venture of Arthur G. McKee and Co.' (Western Knapp Engineering Div.) and Davy Powergas' (a member of the Davy International group). The contract covered process design, engi¬neering, procurement, and construction. The property, identified by Banner Mining Co. in the 1950s and developed by Anaconda, was put into production in 1965 as an open pit mine equipped with a 32,000-tpd sulfide flotation concentrator. The Twin Buttes mine has since become one of the largest earth¬moving operations in the world, excavating some 10 tons of waste per ton of ore. At the original sulfide mill feed rate, the mining fleet moved 375,000 tpd of material (225,000 tpd alluvium and 150,000 tpd of rock). The most significant copper mineral in the ore body is chalcopyrite, which is scattered in pockets of weak mineralization. Cap oxidation has progressed to depths of several hundred feet, principally as chryso¬colla. Present estimates place minable reserves at 347 million tons of sulfide ore grading 0.6% copper and 55 million tons of oxide ore grading 0.9% recoverable copper from 1.25% total copper. The nonre¬coverable fraction is composed of native copper and insoluble copper oxides and sulfides. The oxide ore has been partially stripped, and 25 million tons having a copper content greater than 0.6% have been stockpiled. The stripping of oxide ore to expose sulfides will continue for several years. The copper oxide studies launched by Banner Mining in the 1950s were continued by Anaconda. Process routes investigated included: acid leaching; cyanide leaching; segregation roasting; chlorination, oxidation, and reduction; flotation in combination with leaching; cal¬cite flotation plus leaching; copper oxide flotation; and sulfidization flotation. By late 1968 test work favored a low temperature roast followed by an ammonia-ammonium carbonate leach of the ore. During this period, acid leaching had been discounted because of excessive con¬sumption of expensive acid by the high limestone ore matrix. Restric¬tive SO2 emission controls in 1971 suggested an increase in acid production and availability at a lower cost. Research then switched to acid leaching, resulting in development of the present flowsheet. Mechanically agitated leaching in a cascaded series of tanks was selected in preference to vat leaching after piloting a stirred-tank system. Preliminary testing of vat leaching indicated that inter-vat solution clarification problems could be caused by gas evolution from leaching of high limestone ore. Lack of research time for resolution of this problem, plus success of the pilot agitation system, dictated the final flowsheet selection. In 1973 Anamax decided to proceed with agitation acid leaching to produce liquor for a solvent ion exchange (SIX) and electrowinning (EW) installation. At that time, such systems were proving their eco¬nomic viability, and they allowed direct recovery of high quality cath odes while bypassing the smelting and refining of lower grade cement copper precipitates. The Anamax oxide plant processes a grade of about 1% recovera¬ble copper from stockpiled sources and new mine production. Unit operations include size reduction, agitation leaching, countercurrent decantation washing of residue, pH adjustment of solution, clarifica¬tion, solvent ion exchange, and electrowinning of copper, with a mini¬mum of environmental impact. The feed to the primary crushers is composed of: 1) -10-in. stockpiled oxide ore, which has passed through the mine crusher and has been grade-segregated to allow blending for a consistent feed material. 2) -4-ft ROM oxide ore stockpiled in the early mining operation. 3) -10-in. ore currently being mined. Ore is delivered in 100-ton mine trucks to a dump pocket, where an apron feeder transfers the ore to an inclined 6-in. fixed grizzly. The grizzly oversize passes through a 48 x 60-in. primary jaw crusher, where it is reduced to -6 in. The fixed grizzly undersize and the crusher product are conveyed to a 4-in. vibrating grizzly. Oversize from this grizzly reports to a 7-ft Standard cone crusher, where it is reduced to -1 in. The crusher product and the vibrating grizzly undersize are conveyed to two 8 x 20-ft double-deck vibrating screens that operate in closed circuit with two 7-ft short head cone crushers. Screen undersize (-1/2 in.) is delivered to a covered conical fine ore stockpile with a designed live capacity of 15,000 st. Beneath the stockpile are ten Pioche belt feeders feeding two conveyor belts that supply the milling circuits. Each group of five feeders has two variable speed and three fixed speed drives. Grinding to 95% -48 mesh is done in two parallel lines, each consisting of an 111/1 x 18S -ft rod mill and a 12' x 30-ft ball mill in open circuit. Water is added to maintain a pulp density of 72% solids in the mills. Further water additions are made to the ball mill discharge sumps to create a 60% solids slurry for transfer to the leaching reactors. The nominal grinding rate is 440 tph solids. A splitter box on the product from the mills separates the incoming slurry into two streams, one for the leaching reactors and the other for the pH adjustment reactors. This split is determined by the lime content of the feed material and the pH of solution entering the pH adjustment reactors. Five 30-ft diam by 31-ft high mechanically agitated, rubber-lined leach tanks are arranged in cascade, with gravity transfer from one to another by enclosed launders. Concentrated sulfuric acid (93.2%) from storage is added to the pulp principally at the first leach tank, and the reacted slurry leaving the cascade after a 5-hr residence time at 50% solids is pumped to countercurrent decantation (CCD) wash thickeners.' At this point, most of the soluble copper has been leached from the ore. Up to 250 lb of sulfuric acid is consumed per ton of ore, the acid being supplied in tank cars from a nearby smelter. Leached slurry at 50% solids is washed countercurrently with return raffinate from the SIX plant in a series of four Doff-Oliver center caisson, 400-ft diam thickeners. Solids advance from thickeners No. I through No. 4 to the tailings dam. SIX raffinate advances from thickener No. 4 to thickener No. l, where a pregnant solution overflows to pH adjustment. To optimize solvent extraction, the pH of the pregnant solution from CCD thickener No. I is adjusted from 1.5 to 2.5 by adding unreacted ground slurry (split from the grinding circuit) to the preg¬nant overflow of No. I CCD thickener. The resulting slurry is retained for 45 min in three mechanically agitated leach tanks. CO, generated during leach and pH adjustment is ducted to a demister, where entrained acid droplets are removed. The cleaned CO, and the No. 4 CCD underflow are the only effluents from the plant. The underflow of No. 4 thickener mixes with tailings from the sulfide concentrator and is neutralized. Slurry exits the pH adjustment vessels at about 10% solids and

Jan 1, 1985

At present the feasibility of developing underground facilities for the storage of a number of products including toxic waste, oil, nuclear waste and low pressure gas is under investigation in e number of countries. A possible method of storage is in large excavations, Preliminary ventilation design work has identified that the climatic conditions encountered within these large excavations are a limiting ventilation pollutant within the ventilation system. This paper examines the design of a variety of sizes of excavation from a ventilation viewpoint. The main phases of an excavations lifetime can be divided into four main phases, these being construction, civil and mechanical fitting, storage, full and sealed. The paper details ventilation design options for the first two phases of e vaults lifetime, giving climatic simulations to assess the likely climatic conditions within the excavations for e number of facility depths. The options for climatic control are given and analyzed by means of climatic simulations techniques. l. INTRODUCTION The feasibility of developing underground facilities for the storage of a number of products is under investigation at present in a number of countries. This paper details a possible design for such a facility where the product is to be stored in large underground excavations. A facility layout has been designed with the aim of allowing concurrent construction and storage operations. Thus from a ventilation perspective the facility consists of two circuits , a construction ventilation circuit and a product ventilation circuit both of which are served by an intake and a return surface connection The construction and storage circuits are considered as independent of each other , any interaction in the form of leakage must be from the construction to the storage circuit. From the facility design a ventilation network was developed to assess the ventilation requirements of the facility. In analyzing the pollutant loads for the construction circuit two pollutants were recognised to be critical to the ventilation design , these being diesel exhaust fumes and heat end humidity. In this paper ventilation design options for the construction and civil and mechanical fitting phases of the excavations are analyzed by means of climatic simulation and options for climatic control within the vaults are outlined . 2. FACILITY DESIGN A schematic diagram of a facility design is illustrated in Figure 1. There would be two distinct ventilation circuits , one to service the construction operations and the second to serve the storage operations which occur concurrently with construction , the circuits are separated by ventilation bulkheads . Access to the facility for intake air is provided by two drifts, one to serve each circuit. Two shafts act as returns to surface. The facility consists of two distinct zones for the storage of two types of product. One type is to be stored in smell linear excavations. The second zone is for the storage of a second product in larger excavations. The maximum cross-sectional area and perimeter for the smell linear excavations are 456.25 m2 and 83.2 m, while for the larger excavations they are 440.1 m2 and 86.4 m. Excavation construction consists of three phases: 1. Initial pilot tunnel development between main intake and return to provide through flow ventilation. 2. Enlargement to produce the required finished cross-section. 3. Civil and mechanical engineering work to fit out the excavation ready for storage. It is proposed to excavate the excavations using drill and blest methods utilising diesel equipment. Spoil is to be transported to surface by a conveyor belt system. At any one time the maximum number of working places requiring ventilation will consist of ; 3 storage sites, 2 excavations under construction, 2 excavations undergoing civil and mechanical fitting. [ ]

Jan 1, 1993

By Tanya Arsh, Thomas P. Kwiatkowski, Heather Marsh, Barry Doyle

The Big Walnut Sanitary Trunk Sewer Extension Project consists of two segments, the first a 10' excavated diameter tunnel in rock through the gas producing Ohio Shale formation and the second will be microtunneled through unconsolidated water-bearing deposits. Relatively large quantities of methane gas have been encountered in the Ohio Shale. In the softground segment, the sands and gravels contain large water storage capacity and contain shallow residential wells. This paper will present an evaluation of potential gas inflows in the rock tunnel, design considerations for contract documents preparation to inform bidders as to the volumes of gases which may been countered and design options for construction of an impermeable shaft excavation support system to insure residential wells remain in service.

Jan 1, 2001

The last time Mining Engineering presented an issue with a special focus on Canadian Mining (ME, August 2008 pp. 28 to 40) things were going well. A feature story took a look at Xstrata?s Nickel Rim South Mine in Sudbury and the booming Canadian oil sands were discussed at length. Potash prices were soaring, large diamonds were being found and British Columbia was launching plans to find more workers. How things have changed in six short months. What began as a mortgage crisis grew into a credit crisis, then mutated into a financial crisis, that has taken its toll on the value of bonds, loans, stocks, real estate and commodities. Miners that were flying high on unprecedented commodity prices six months ago have begun scaling back with delays, shut downs and layoffs as they struggle to survive this most recent economic downturn.

Jan 1, 2009

By Sidney A. Suhler

The persistent requirement for methods and equipment capable of detecting hazardous anomalies in advance of underground mining has led to the development by the U.S. Bureau of Mines of a directional radar probe. The probe operates from boreholes drilled from the surface into the underground region to be mined. The engineering model radar was completed in early 1982 and field demonstration tests were performed in May of that year at a selected coal mine. Preliminary in-situ electromagnetic tests were performed at several candidate coal mines to evaluate the radio-frequency characteristics of the coal. A coal mine in New Mexico was selected on the basis of low EM propagation losses in the coal and the presence of an extensive coal seam displacing fault as a radar target. The borehole radar was operated in two vertical boreholes which intersected the coal seam at approximately 25 and 40 feet from the fault interface. Radar reflections from the coal/ rock interface were detected in both tests. Underground tests in a horizontal borehole in the coal were less successful because of interfering reflections. Additional borehole-to-borehole tests were performed with a separate ground penetrating electromagnetic system to obtain radar range calibration data. The coal was found to be bounded by very lossy roof and floor sandstone and shale while propagation through the coal seam was obtained at distances up to 175 feet between test boreholes. Coal seam continuity was indicated by the hole-to-hole experiments through a section of the seam previously thought to be completely cut off by the fault.

Jan 1, 1983

By Roy Norcross, Stephen Gos

For over 100 years Degussa has worked together with the min­ing industry not only providing quality products but also develop­ing technologies to support these products through value added goods and services. For cyanide, these technologies include leach enhancement processes such as PAL™ and Solidox™, and cyanide detoxification with peroxygen based processes such as SILOX™ and Caro's acid using our DegOX™ technology. Degussa has also made important advances in how sodium cyanide is packaged and shipped with our liquid NaCN plant joint venture with MSI, CYANCO in Winnemucca, Nevada, and our Advantage SLS™ solid to liquid cyanide delivery system. All of these innovative technologies developed to support NaCN in mining, provide value to our customers and show Degussa's commitment to Responsible Care·11.1 and dedication to product stewardship. With Responsible Care and the customer in mind, Degussa has developed Advantage CCS™ cyanide control system, which will soon be available for the North American market. Currently there are several CCS units in service installed by Degussa AG (Germany), and we are in the process of designing the next gen­eration of the CCS which should be completed by late '98. Based on our experience working with gold and silver mines all over the world, there appeared to be an opportunity to further assist our customers by providing a better more automated way to control their cyanide additions. By providing the mine with an accurate method for maintaining their desired cyanide levels in their leach circuits, we could help them avoid underdosing and the associated gold and silver losses, and overdosing the cyanide which not only wastes cyanide but may increase treatment costs as well. In the early 1990's, when we began to introduce our CCS units, there were several cyanide controllers and on-line analyzers avail­able. However, they appeared to be too complicated and not made to stand the harsh conditions inside a mill. This resulted in exces­sive downtime and poor analytical results. We also found that many units would be installed but not commissioned by the sup­plier. Based on these observations, along with filtration and con­trol problems on some existing units, Degussa decided to design its own cyanide control system based on our extensive knowledge of cyanide chemistry, using the best components available worldwide.

Jan 1, 1998

By Ernest Y. Baafi

The usual tasks performed by a mine store include .removal, replenishment, ordering and deletion of items and updating of stocks. A personal computer Mine Store Inventory Database System MIDSYS for monitoring stocks in such a store is presented. The system consists of series of relational databases developed in dBASE III+ environment. The system has three main modules comprising of a store management module, a display module and an employee-store operation module. The third module is useful in tracing movement of store goods. The MIDSYS is menu .driven with help functions at all levels.

Jan 1, 1992

By J. M. Applegate

In the same way that a blueprint communicates information about a structure, a useful systems architecture should provide information that guides the construction and implementation of computing systems. Taking the blueprint analogy a step further, a plot plan can also show where in the "bigger picture" a particular design fits (if in fact it does) and what a builder needs to know about the environment in which he or she will operate. In the context of business systems, a meaningful architecture should convey the following: 1. The primary purpose of computer based systems relative to particular task or operation. 2. The relationship of systems to each other and an indication of their interaction and dependencies. 3. The relationship of systems relative to the organization and its objectives. 4. Indications of where IS/IT resources can best be allocated to support the organization. 5. The overall context in which new systems and technologies can be assessed for both their impact on current system and on the organization itself.

Jan 1, 1998

By D. A. Norrgran

The term "secondary recovery" has recently brought on a new meaning in view of the depletion of natural resources, energy conservation, plant optimization, and the environmental consciousness that has led to hazardous waste management, recycling, and secondary processing. Many secondary recovery processes are being developed applying mineral processing technology. Gravity separation, magnetic separation, and flotation have all emerged as implicit methods for recovering residual values from various process streams and hazardous constituents from waste streams. Recently, a technique for concentrating metallics has been successfully reintroduced. Although the concept of the eddy-current separator was developed over a century ago, (Patent 400317 issued to Thomas Edison on March 26, 1889) it was not until this last decade that it gained prominent acceptance. The evolution of permanent magnets has provided a cost effective alternative for the generation of high intensity magnetic fields. High energy permanent magnets have substantially reduced the capital and operating costs over the electromagnetic circuits employed in antecedent eddy-current separators. Specifically, in recent years, the strength of permanent magnets has increased several fold with neodymiun-boron-iron rare earth magnets now providing an energy product of 35 million gauss-oersted. Figure 1 shows the evolution in the strength of permanent magnets. The development of these rare earth magnets has led to the design of circuits possessing a magnetic force an order of magnitude greater than that of conventional permanent magnetic circuits.

Jan 1, 1991

By M. Javier

"Mining is the main activity that supports civilization. Actual mining presents contradictory concept to the health of the planet. Its business model is linear, fragmented and characterized by inefficiencies in the utilization of water, energy and mineral resources which generate waste and pollution. Before mining begins, it is critical to determine the vulnerability of the ecosystem and after mining, it is critical to determine the depletion of nature. Attending to these vital matters will require quantifying and measuring them. The purpose of this study is to provide and establish the metric to assess the performance and manage a sustainable future for our existence and that of our planet. This index is defined to measure and control Nature Friendly Sustainability (NFS) based on understanding nature. This index will determine the condition of nature constructed on the measurement of physical, chemical and biological equilibrium. Proposing a new mindset for mining design to satisfy nature’s needs would be to offer the same opportunities to future generations. Hence, sustainability is synonymous with equilibrium under a limited ecosystem. Nature is interconnected. Finally, this index of NFS is readable, standardized and relevant to keep nature’s needs in equilibrium. Establishing and NFS index is the next metric for humanity. INTRODUCTION There are a multitude of definitions of what sustainability is. Most of them are defined in terms of the corporate entity from which they emanate. The classical definition of management states that, “if we do not measure it, we cannot manage it.” Management of ecosystems is the definition of sustainability. Indicators of quantity and quality of sustainability are vital in order to create a metric for sustainability. These indicators will measure the depletion and degradation of nature as they occur through human intervention. The first step is to create a metric of sustainability to simplify its definition. The definition of sustainability is based on whether or not you consider nature to be finite or infinite, which is described in Nature Friendly Sustainability (NFS) [1]. The definition of NFS applies to any anthropogenic activity with an understanding of the equivalent activity in nature. That is to say, human activity with nature requires balance and equilibrium in order to be sustainable. The importance of this equilibrium is quantified in a set of metrics in order to establish measurement and acknowledge indicators for our dependence on nature. Sustainability is synonymous with equilibrium in any ecosystem that is limited and fragile. In the graph is the explanation of sustainability definition. See Graph 1"

Jan 1, 2017

By Rolf J. Wesely

Recent events in The Peoples Republic of China indicate that a major effort is underway to increase trade with the western world. Gold production contributes to China's ability to participate in international trade. Consequently, the Chinese government places a high priority on increasing gold production. Many of the operating gold mines in China contain refractory ores that to date have not been efficiently treated. Figure 1 illustrates the description and location of a few of China's major gold mines. China recognizes that the technology necessary to economically treat this ore has been developed in the United States and other western countries. The country has therefore begun to seek assistance in evaluating several potential projects. Organizational structure Gold mining and processing in China is directed by the China National Gold Corp. (CNGC), headquartered in Beijing. The agency has a director in each province who is responsible for exploration, mining and processing. CNGC uses the services of two engineering organizations for metallurgical testing, process development and design engineering for their projects. The largest engineering organization is the Central Engineering and Research Institute for Non-Ferrous Metallurgical Industries (ENFI), also located in Beijing. The second engineering organization is the Changchun Gold Design Institute (CGDI), located in Changchun Jilin province.

Jan 1, 1993

By Alim Elibol, Rosbel Jimenez, Mustafa Can Suner, Deniz Tuncay, Zach Agioutantis

LaModel is a displacement-discontinuity variation of the boundary element method, which is utilized to analyze the displacement and stress in flat-lying, tabular orebodies. In coal mining, the accuracy and reliability of LaModel are proven with the utilization of the Mark- Bieniawski coal pillar strength and the stress gradient formula with proposed methodologies. However, the application of LaModel is limited to coal mines due to the default coal pillar strength properties. Recently, the stress gradient functions have been established and used to derive concentric rings of zones to simulate stone mine pillar yielding in LaModel. Also, to gain a robust understanding of the brittle failure mechanism and its effect on pillar strength, an S-Shaped failure envelope, where rock mass' cohesive and frictional strength components mobilize as a function of confinement (e.g., minimum principal stress), has been implemented into FLAC3D software. Therefore, by employing brittle failure criteria, the pillar strength stages at various width-to-height ratios and different pillar dimensions are estimated for four benching stages. The estimated pillar strengths and stress gradients for benching conditions are then used to calibrate LaModel in-seam material properties and compare stresses computed by LaModel and FLAC3D. Consequently, this study aims to increase the safety measures in the stone mining industry by implementing the practical use of LaModel for underground stone mines' initial development to various stages of bench mining.

Jun 25, 2024