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By R. A. Hemstock

AREAS in which the surface de-posits consist of organic material -known in some parts of Canada as muskeg and in Europe, more generally, as peat lands -have long been some of the least rewarding of lands of the north temperature zone. Even in such countries as Great Britain, Holland, and Denmark where a good deal of incentive exists to develop all available land, the use of peat land has been negligible except as a source of fuel. Only recently have efforts shown promise in re-claiming these lands for farming or for forestry. Russia has large areas of peat and use is made of it for power generation. The Russian people have also ?developed a variety of machines for handling peat, which would indicate that they are well ahead of the Wes tern World in their technical and physical ability to solve some of the problems. Certainly in Canada, where there are over 500,000 square miles of muskeg, the economic aspects of this problem are important. This is especially true in considering the shifting emphasis to northern development. Not only is muskeg in possession of great stretches of terrain, thereby rendering it useless for agricultural purposes, but it is apparently moving into forested areas and reducing their productivity. In addition, it lies as a great barrier to movement in the search for and development of such natural resources as petroleum, natural gas and minerals generally. This situation has long been recognized in Canada but only recently have organized efforts been made to study the problems and search out ways of overcoming them.

Jan 1, 1958

By A. J. Miller, G. R. Brophy

THE Grossmann principle1 for the calculation of hardenability of steel from composition is attractive because of its simplicity. It postulates that the hardenability of a steel for any particular grain size may be expressed in terms of an ideal critical diameter, which is the product of an ideal critical diameter for a "pure" iron-carbon base multiplied by a succession of factors for each element of composition contained, including the incidentals. It infers that the multiplying factor for a given quantity of an element is constant for all combinations of composition. Grossmann has stated that in the great majority of cases the experimental values of hardenability are found to be well within 10 per cent of the calculated values. The validity of the scheme has been confirmed in principle by Crafts and Lamont2,3 and by Kramer et al .4 Their results differ from the original in the magnitude of the effect of some elements but, since they accepted the product concept and followed its direction, it is to be expected that similar results would be obtained. Crafts and Lamont, in their second paper, recognized that the factor relations for manganese and nickel were not continuously linear, but beyond certain critical amounts increase sharply. Austin, Van Note and Prater5 demonstrated nonlinear relations between hardenability and alloy contents. Their curves for chromium, silicon, manganese and nickel were all convex upward to show decreasing incremental effects. They concluded that Grossmann's factors underevaluate the hardening effect of low percentage additions of these elements, and overevaluate the larger additions. [ ] More recently W. Steven6 has found that the factor method fails when applied to complex steels containing two or three principal alloying elements other than carbon. Multiplying factors derived from his results bear a complex relation to composition and are not constant for a given amount of an element as the base composition varies. C. A. Liedholm7 found that, using either the Grossmann or the Crafts-Lamont multiplying factor values, not only were

Jan 1, 1945

By J St George

Much of AucklandÆs transport infrastructure has been developed on surface with little or no consideration of underground options. Current and planned transportation routes are now facing high costs due to land values and increasing environmental resistance to surface development. The option of utilising underground space becomes a feasible investment decision for these links as well as being the only option to develop the rail network within the inner city area. Transportation tunnels offer a quieter, more energy efficient means of getting around with minimal impacts on the surface environment. One of the major impediments to tunnelling is the high construction cost, which is partly related to the risks of encountering unexpected ground conditions and/or the possibility of causing surface ground deformations which could damage structures. The geology of Auckland has had substantial investigation through various studies and projects. The sediments of the East Coast Bays Formation (ECBF) underlie most of the Auckland urban area. It is classified as a soft rock and is a suitable material to tunnel through using either a tunnel boring machine or a roadheader. This paper reviews the limited amount of tunnelling completed in the urban Auckland area, together with the international advancements that have been made in the tunnelling industry. From the known features of the local geology and the problems encountered historically, the likely risks of tunnelling in Auckland are presented and ways in which those risks could be reduced and managed, are discussed. In addition, contractual arrangements between client and contractor are assessed with respect to complicated projects (such as tunnelling), so that the risks can be managed to create efficient infrastructure routes with reduced costs.

Jan 1, 2008

By J. Sanko

When faced with the task of designing a process control system the control engineer must consider the following: 1. The type of process to be controlled and the manner in which the process must be controlled (the algorithm). 2. The type of equipment to be used to implement the control system. 3. A means of describing the control system for use in the following areas: a. Project engineering. b. Procurement of the control system equipment. c. Plant startup. d. Operator training and reference.

Jan 1, 1981

By Balladares V. Eduardo

Most of the arsenic contained in copper concentrates is removed in the gas phase during the smelting and converting processes and, according to recent environmental regulations, it is required to fix it in a solid stable form. In this regards, ferric arsenate has been reported as thermal and aqueous stable compound. Therefore, various alternatives for treating gas containing arsenic were considered in this work. From data obtained at laboratory scale on fixation of arsenic using iron oxide, a new process to treat copper concentrates containing arsenic was evaluated. The effect of temperature, oxygen potential and the sample porosity on the fixation of arsenic contained in a gaseous stream was studied, and the iron oxide converted into ferric arsenate was up to 10%. The obtained results suggest a new alternative for gas treatment with an interesting and attractive technical development. The arsenic was retained as ferric arsenate with thermal and aqueous stability, and it allows a safe disposal keeping the environmental restrictions. The kinetics parameters are used to scale up laboratory results to higher processing rates.

Jan 1, 2005

By William L. Rose

Production scheduling is an integral part of intermediate- and long-range open-pit mine planning, affecting equipment selection, manpower requirements and project economics. The development of mining phases, or pushbacks, is discussed in conjunction with generating the best spatial extraction sequence. An approach to scheduling production from these mining phases is then described. Using computers and a production scheduling algorithm, the impact of cutoff grade and advanced stripping policies can be evaluated through sensitivity studies to maximize the return on project investments.

Jan 1, 1985

By F. P. Schwarz

Even in an otherwise care-fully done sampling procedure, reducing subsample weight, or splitting, when the grain size of material is too large commonly generates significant error. Such error can be estimated from the standard deviation of differences between values of PAIRED ASSAYS. Samples from split-ting steps immediately before comminution, and showing a restricted range of grade, generate paired assays. Splitting steps characterized by relative standard deviations exceeding 16% generate nonrepresentative data. Such steps should be redesigned to optimize reliability of assay-dependent studies. A sampling scheme can be graphically characterized, and then redesigned as appropriate, using a SAMPLING NOMOGRAPH. Use of the nomograph avoids continued replication of assays. Generally at a splitting step, excessive error can be reduced by comminuting more material. Unnecessary effort can be mitigated by comminuting less finely and/or by splitting to a smaller weight.

Jan 1, 1992

By Ralph E. Magnuson

The quality of our environment is of great importance to all of us. Today, there is a great public concern about the degradation of our air, land, and water and the resultant slow death of our planet Earth. The miner has always been concerned with his environment. Historically, mining has been a part of the frontier. As a result, the miner has pioneered and developed many parts of the world. In the beginning, he had to hack out a place for his mine, himself, and his family. He was given accolades and praise for his accomplishments. Now, however, he is attacked as a ravager of the landscape. It was and is no different on the Marquette Iron Range in Marquette County, located in the Upper Peninsula of Michigan. Iron ore was discovered in 1845 and mining was begun by 1848. Over nearly 1 ¼ centuries, a total of 379,197,000 tons have been shipped to market. Ports, docks, railroads, and towns all had to be built in order to get that tonnage out to iron and steel makers. In those early days the environment had to be mastered, not pampered.

Jan 1, 1970

By D. Majuste

This paper describes an experimental approach to evaluate the effect of organic impurities or even additives on metal electrowinning and product quality. In addition to electrowinning tests and electrochemical measurements, the approach includes organic analysis by Fourier Transform Infrared spectroscopy and gas chromatography; video monitoring of the reaction interface; and product characterization by using scanning electron microscopy, crystallographic texture and bending tests. The mechanical behavior of metal cathodes was assessed with a customized bending device that is able to bend the cathodes up to angles similar to that of the stripping machine. In this work, the effect of a potential organic impurity, lubricating oil, on the production of electrolytic zinc is taken as a case study. The findings of the investigation allowed a better understanding on the role of this organic on energy consumption and product quality and a qualitative prediction for the behavior of Zn cathodes during the stripping operation. Simple control and optimization procedures resulted in significant energy savings.

By M Griffiths

This paper outlines an approach to high solids slurry pipeline design with data generated from a closed pipe-loop test system. The pressure and flow rate data generated is used to develop a pseudo-shear diagram for the purposes of system design. Following this approach enables the design of a full pipe flow system maximising system life and reliability. The alternative free fall system is explained and the disadvantages highlighted.Environmental and social considerations are discussed; mainly water and land use, and how designing for high solids slurry pipeline systems can be used improve these aspects of a mining project.Also discussed is how the use of high solids slurry pipeline systems can help to mitigate the risk associated with surface tailings storage facility failure, with the Bulyanhulu project used as a positive example.

Aug 8, 2011

By M. Mirnezami, J. A. Finch, S. Uddin

A fast, reliable and practical way of measuring zeta potential using sedimentation potential method is proposed. A cell was designed along with the instrument control software to determine the required variables simultaneously i.e. sedimentation potential, specific conductivity, volume fraction of solid as well as pH. High purity alumina and silica powders were used as test samples. Measured zeta potential using the proposed technique was comparable with the results by electrophoresis.

Jan 1, 2009

By M E. Karmis

Traditional coal mining planning seldom considers key æsustainability factorsÆ such as: societal impacts in the area; jobs (both created and lost); dislocation of towns and residences; impact on neighbouring communities and individuals; infrastructure concerns; post-mining land use (except when limited by law or other factors); habitat disruption and reconstruction; long-term economic impacts in the community; and net long-term community benefit. This paper presents a systems engineering approach based on the premise that systems can only be optimised if all factors are considered at one time. In theory, coal mine designs can be optimised for return on investment, environmental protection and sustainability. Using this approach, the permitting process may be quicker and less costly, relationships with neighbours, communities, environmental groups may be improved, the mining industry may be seen as a positive for the short-term and long-term and the mining industry may increase profits. This paper discusses geographic information system (GIS) tools that may be used to incorporate ecological and other sustainable development concerns into models of coal mine sustainability performance. Along with coal production cost and value information obtained from past and present coal mining operations, GIS data are used to develop mathematical cost and equation models. By analysis of on-the-ground data, the parameters to be included in these models are identified, the relationships between these parameters quantified and the models developed. The paper also discusses the next phases of the work to be completed once the data is obtained and the models are adjusted and validated. At that time, site-specific information will be input into the models and the approach to mining a particular property evaluated and optimised for financial rate-of-return and other desired outcomes, such as preservation or enhancement of sustainability values. Finally, the paper will examine how this approach can be combined with traditional mining engineering considerations in order to develop an optimised mine plan for a specific mining property.

Jan 1, 2009

By Pinnaduwa H. S. W. Kulatilake, Biao Shu

The intact rock properties and discontinuity properties for both Devonian Rodeo Creek (DRC) and Devonian Papovich (DP) rock formations that exist in the selected open-pit mine were determined from tests conducted on rock samples. Special survey equipment, which has a total station, laser scanner and a camera, was used to perform remote fracture mapping in the research area. From remote fracture mapping data, the fracture orientation, spacing and density were calculated using more refined procedures compared to what exist in the literature. Discontinuity orientation distributions obtained through remote fracture mapping agreed very well with the results of manual fracture mapping conducted by the mining company. The GSI rock quality system and Hoek-Brown failure criteria were used to estimate the rock mass properties combining the fracture mapping results with laboratory test results of intact rock samples. Fault properties and the DRC-DP contact properties were estimated based on the laboratory discontinuity test results. A geological model was built in a 3DEC model including all the major faults, DRC-DP contact and two stages of rock excavation. The built major discontinuity system of 44 faults in 3DEC with their real orientations, locations and three-dimensional extensions were validated successfully using the fault geometry data provided by the mining company using seven cross-sections. Numerical modeling was conducted to study the effect of boundary conditions and lateral stress ratio on the stability of the considered rock slope. For the considered section of the rock slope, the displacements obtained through stress boundary conditions seemed more realistic than those obtained through zero velocity boundary conditions (on all four lateral faces). Stable deformation distributions were obtained for k0 in the range of 0.4 to 0.7. Because the studied rock mass is quite stable, it seems that an appropriate range for k0 for this rock mass is between 0.4 and 0.7. The displacements occurred between July 2011 and July 2012 due to the nearby rock mass excavation that took place during the same period; they were compared between the field monitoring results available from the mining company and the predicted numerical modeling results and a good agreement was obtained. Overall, the successful simulation of the rock excavation during a certain time period indicated the possibility of using the procedure developed in this study to investigate rock slope stability with respect to expected future rock excavations in mine planning.

Jan 1, 2015

By K. W. Grubaugh

The recently enacted federal surface mine law (P.L. 95-87) will increase further the complexity of securing a reclamation permit. This law intensifies the need to present the required reclamation plan in a thorough and comprehensive manner. One plan format, that used in construction performance contracts, offers promise of filling this need. Reasons for using the format of expressed, bilateral, negotiated contracts common to the contruction industry, and the salient aspects of an application which uses this format are reviewed. Advantages of this procedure are seen to be improved mine planning, awareness of the total design job, potential for improved speed of permit acceptance and improved cost control.

Jan 1, 1978

The following is a discussion of a new approach to safety when developing or applying a new mining technology. In the form of an engineering process, the following approach had its inception in the military and aviation industries and is also very strongly evident in the chemical industry.The process has been developed and applied in the mining industry by the author. It is called 'Incremental Development and Management of New Technology'.The process is a composite of carefully selected System Safety Management, System Engineering and Financial techniques and methods. It consists of modules which can be modified to suit the requirements of a specific project. Modules provide an organised framework of activities to facilitate a gradual acquisition of pertinent knowledge and information and to enable progressive evaluation or verification of produced outcomes against specified requirements.

Jan 1, 1992

By J. H. H. Chamberlin

"In the Introduction the author briefly discusses the company history as it relates to the development of its contracts with the Japanese steel mills. The main part of the text describes how Coleman Collieries Limited approached the problem of mining coal profitably in thick, steeply inclined seams. For many years a basic room-andpillar system was worked by conventional methods. Main roadways were driven on strike across the mineable area. These roadways acted as haulage routes for coal, materials and men. Rooms were developed to the rise of the main haulage route by pairs of men using air-operated hand picks. As these rooms advanced the miners would lay and extend a sheetiron chute down which mined coal would gravitate to a controlled loading point, where it was loaded into trains of mine cars. Connecting roadways or ""OFFS"" were driven at predetermined intervals between adjacent rooms, forming pil1ars or blocks. Extraction of the blocks followed on a line conducive to good strata control some distance behind the developing rooms. A need for higher productivity, expansion of the operations and a scarcity of qualified miners resulted in the company deciding to mechanize its underground mines. Joy 6 CM continuous miners and 10 SC shuttle cars were selected as being machines that could reasonably negotiate the problems associated with the pitching seam. The equipment, nonetheless, has definite limitations and Coleman therefore developed a modified version of the room-and-pi11ar system such that the miners and cars could work on cross pitch. In the area described, main roadways were driven to the rise on an average gradient of 12 degrees. Panels, which consisted of two parallel roads with interconnecting cross-cuts, were then developed on strike to a boundary point. Blocks formed in the development of the panels were subsequently extracted on retreat. Problems associated with each phase of the operation are thoroughly discussed, together with roadway support methods and equipment used for the conveyance of coal and materials."

Jan 1, 1972

By R. E. Hamilton

Automation is a word whose meaning has been broadened by popular usage to include any labor saving device. We with restrict our usage to the replacement of human judgement by instrumental measurement and mathematical analysis in the control of industrial processes. Mineral concentration is an area which has resisted automation because of the great difficulty in developing measuring instruments which can exist in the rugged environment and can measure useful properties with acceptable accuracy. This is not the only factor limiting progress, but until recently it has been of over-whelming importance. The development of on-stream X-ray analysers, magnetic flowmeters and nuclear density meters for mineral slurries has eliminated this obvious barrier and is enabling us to locate and attack the less obvious problems which still limit our ability to automate concentrators. If we examine the history of automation in industries which are highly automated we find that it has usually gone through three distinct phases. The first phase has been regulation. This is the simplest form of control and involves manipulating some variable whose value is of no importance in order to maintain the value of some other variable which is important at a constant specified value in spite of disturbances which may occur in other variables which affect it. A simple example is the use of a control valve to maintain a constant flow of fluid in a line in spite of changes in pressure in the vessels at the ends of the line. The position of the valve stem is of no consequence, as long as it is within its operating range. Unfortunately we soon run out of variables which can be

Jan 1, 1971

By T Walkemeyer, R Elliott, D Chang-Martin

Over the past decade, discrete element method (DEM) simulations have seen increasing adoption by the resources sector to inform the design of materials handling equipment such as transfer chutes, bins and hoppers. But, if ‘all models are wrong, but some are useful’ (Box, 1979) what approaches are available to check that a DEM simulation is useful? How to avoid garbage in equals garbage out. This work considers what properties of bulk solid flow behaviour are important to transfer chute simulation. Cohesive bulk solids (such as sticky iron ore fines) can develop sufficient strength to form a stable cohesive arch, this phenomenon is not well predicted by measurements of angle of repose. This work presents a two-part approach to the development of a useful DEM model that can be used to add value to the design and optimisation of bulk materials handling equipment. Part 1 is the calibration of not just one, but a range of material models chosen to envelope the range of anticipated materials that will be handled. This work describes the DEM simulation of a batch of direct shear cell tests to develop material models that can be measured by the same metrics routinely used to characterise the flowability of cohesive iron ore fines. Part 2 of this work describes systematic methods for validation of the transfer chute DEM simulations. The DEM model is only useful if it can adequately represent the typical problems observed within a transfer chute, such as blockages due to build-up and cohesive arching. Proper validation requires good observations. Validation examples of site observations are shown side-byside with simulations to demonstrate the adequacy of the DEM model and calibration approach. DEM simulations have the potential to add significant value by allowing engineers and designers to predict material flow-through equipment based on a range of material properties, allowing for stress testing designs and making iterative improvements.

Sep 18, 2023

By Steve Klein

Weak rock is an important consideration in tunnel design and construction due to the difficult ground conditions that are often encountered. Nevertheless, when conditions are favorable high advance rates can be achieved leading to economical tunnel construction. Successful construction of a tunnel in weak rocks depends on correctly anticipating the behavior of these unique materials. The objective of this paper is to provide guidelines that can be used to accurately classify the performance of weak rock in tunnels.

Jan 1, 2001

This paper describes some experiences in the design of flotation reagent schemes for the efficient flotation of complex gold ores containing free gold and/or gold associated with easily flotable sulphide minerals such as chalcopyrite and bornite. Historically, the design of gold flotation reagent schemes has been based primarily on experiences using high dosage levels of water soluble charged collectors such as xanthates and dithiophosphates and carefully controlled regions of pH. This approach has been effective with gold associated with complex sulphide minerals, in particular gold associated with iron sulphides such as pyrite. An alternative two-stage reagent approach is presented that is applicable to certain types of gold ores. This approach involves using very small dosages of uncharged water insoluble collectors at natural ore pH followed by a modified bulk flotation reagent approach for the second stage. The reasons for utilising this approach, when applicable, are discussed and illustrated with examples.

Jan 1, 1997