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What is your assessment of the current state of the minerals industry? It is no understatement that domestic mining is facing a severe crisis at this time. The sharp decline in commodity prices and demand is putting a great strain on domestic and worldwide mining, causing major declines in profits and market capital of mining companies. This, in turn, has lead to major production cuts, layoffs, shut-downs of operating properties, and the deferral of new and expansion projects. These changes in the minerals industry have played a major role in the health of the economy. Operationally, the industry continues to develop new technologies that are making our work more efficient, more cost effective and more environmentally acceptable and safe. During downturns like this, companies generally pay closer attention to operational efficiencies and process optimization. Historically, new technologies and processes tend to be developed during down markets, and I believe we will see the same thing as companies strive to preserve liquidity and maintain or improve their margins. On the positive side, the drop in commodity prices has resulted in a reduction in operational costs, as the costs for fuel supplies and construction materials have decreased.

Jan 1, 2009

By L. A. Clark

Although vein-, syenite-, and pegmatite-type deposits are known in Saskatchewan, recent intense exploration stems from discovery of several exceptionally high grade uranium and uranium-nickel deposits locallized near the basal unconformity of the 1.3-1.4 b.y. Athabasca Sandstone Formation. Graphitic basement rocks and post-Athabasca faulting or brecciation coincident with the unconformity are important in locallizing uranium deposits which form as tabular, shoe lace-like bodies with grades averaging over two percent and containing up to 50,000 tonnes U308. Some deposits have similar nickel contents. A few published sandstone analyses average 0.8 ppm uranium while basement granitoid and meta-sedimentary rocks vary from 0.5 to 20 ppm. In the proposed genetic model, traces of uranium are leached from these rocks by oxidized formation waters sweeping through the sandstone and along faults. Solutions are reduced and uranium is precipitated as basement graphitic meta-pelites are encountered along brecciated fault zones.

Jan 1, 1979

By Hiroshi Yamazaki

The paper describes prediction, control and validation of face pressures, and special TBM features for the bored tunnels of the New Metro Rail City Project, Perth, Australia. The selected EPB-TBM passed below a heritage bridge and the operational Perth Railway station in ground conditions consisting of fully saturated uniform sand combined with shallow overburden and a horizontal alignment radius of only 135m. Therefore, strict control of volume loss, TBM operations and ground movements was vital requiring continuous evaluation and adjustments to TBM operation parameters. The paper discusses the effectiveness of applied TBM face pressures and the used foam/polymer soil conditioning which was measured against achieved volume loss and the predicted range of ground settlements.

By William H. McLemore

Geologists searching for carbonate rocks suitable for chemical uses traditionally have relied on extensive laboratory testing in order to locate strata or zones that might be suitable for mining. However, when considering the significant time and costs involved in sampling and performing chemical analyses, any exploration technique whereby fewer samples and analyses are needed would be of great value. In other words, if the exploration geologist could "zero-in" on select areas, considerable time and money could be saved. In general, the major-element chemistry of carbonate rocks is determined by the abundance of the minerals present. CaO occurs with CO2 as the mineral calcite, which is the primary mineral comprising allochems, matrix and sparry cement; MgO is found in high-magnesium calcite (many calcite fossil species contain appreciable amounts of MgO in solid solution), dolomite, and chlorite; iron occurs in pyrite and in limonitic stylolites, as well as in chloritic and glauconitic clay minerals; materials containing abundant Si02 are microcrystalline quartz (chest) silt-sized quartz, and clay minerals; and Al203 is found primarily in illitic, kaolinitic, and chloritic clay minerals. The presence or absence of these minerals determines the chemical composition of the carbonate rooks.

Jan 1, 1983

By L. J. Vincze

The program of study of pellet binder materials was begun by the ORF in 1963 to examine various Canadian materials as substitutes for bentonite which is imported in large tonnages (199,270 tons in 1969) from the U.S.A. for Canadian pellet plant operations. Most of the raw bentonite used in Canada originates in Wyoming, North Dakota and more recently Greece, resulting in relatively high transportation costs to pellet producers. Some Canadian bentonites available in Western Canada (Alberta) can be beneficiated for uses as pellet binders but could not compete in cost with U.S. sources due to the cost of beneficiation and the higher rail transport charges to Eastern Canada. It is difficult to find a substitute for bentonite, and many materials have been investigated by research groups but, so far, no economic substitute is in use. However, some success is apparent in studies of low cost materials such as clays, sea weed, peat moss and low grade coal, The work done by the ORF over several years has covered systematic test¬ing of Ontario clays, lignite, some types of tree bark, waste sulphite liquors of various kinds, and peat moss as binders for iron ore pellets. The major effort has been concentrated on peat moss and has included a study of the influence of different additives. Since analysis of peat moss for humic acid is difficult and time consuming, a certain amount of time was devoted to development of improved methods, the most useful of which was a spectrophotometric method based on extraction of peat by sodium pyrophosphate for determination of humic substances. In the present paper, only the most recent work concerning the use of peat moss with suitable additives is discussed in detail, since it is the most conclusive and best documented portion of the program.

Jan 1, 1971

By P. D. Lafleur

A concerted effort to determine the quantities and effects of trace elements in the environment requires the application of a number of different analytical techniques in the same or in different laboratories. The interpretation of analytical data is often difficult because of differing results between analysts or even by the same analyst at different times. Standard Reference Materials (SRM), which are certified for their trace element content and are in a matrix similar to the one of interest, can greatly increase the accuracy of analysis and the reproducibility between laboratories. The United States National Bureau of Standards (NBS) has developed a number of SRMs applicable to the determination of trace elements in environmental materials. Two of these, SRM-1571, Orchard Leaves, and SRM-1577. Bovine Liver, are excellent for biological tissue analyses. Several new standards are of value for fossil-fuel analyses. These are: SRM-1632. Trace Elements in Coal; SM-1633, Trace Elements in Fly Ash; SM-1634, Trace Elements in Residual Fuel Oil: and SRM-1635, Trace Elements in Gasoline. In cooperation with the US Environmental Protection Agency, the NBS has recently concluded an interlaboratory comparison involving analyses by more than 60 laboratories on these fossil-fuel materials. The resulu of this intercomparison and the broad range experience with the biological materials will be presented showing both intratechnique and intertechnique variations, and the sensitivities and comparisons with the values certified by NBS.

Jan 1, 1975

By R. D. Hutchinson

I consider it an honour to be the opening speaker in this afternoon's session on "Canadian Exploration". I also think it most appropriate that this joint meeting of the MMIJ and AIME should consider this subject, because Canada is a major exporter of mineral products and Japan and the United States are our two largest customers. Clearly, therefore, both countries have a valid interest in developments on the Canadian minerals scene. I represent the Mineral Development Sector of the Canadian Department of Energy, Mines and Resources. I will therefore speak from the point of view of the Federal Government. At this point I would like to acknowledge the help and constructive criticism I have received from several of my colleagues in Mineral Development Sector in the preparation of this paper. In any discussion of exploration in Canada, it is essential to emphasize at the outset that Canada has a federal system of government, with powers shared between Ottawa and the provinces. Under our constitution, the federal government has jurisdiction over the north, and over offshore areas, while the provinces own the natural resources within their boundaries. They control the systems of land acquisition for exploration and the terns under which mining titles are issued, and are therefore able to determine the rate and conditions of exploration and development of these resources. It follows that the Federal Government can influence the exploration and development of the provincial resources only indirectly by consultation with provincial authorities. However, once the resources are developed and begin to flow to market, the Federal Government can exert a much stronger influence because of its constitutional right to control both inter-provincial and international trade, as well as through its general fiscal and tax powers.

Jan 1, 1976

By B. Beatty

Discussion by B. Beatty This is a response to M.J. Hrebar's paper, which tracks in detail the highly productive stripping capabilities of modern large bulldozers at two separate installations. It proves the old adage "economies of scale" and quantifies the advantage of being able to move large loads of dirt over comparatively short haul distances by sliding rather than carrying the load. This discussion examines whether a bulldozer is the most efficient way of using this geotechnical principle. Case 1 - Study eastern US: Contour coal stripping application The energy consumption for the Case 1 mining method (eastern US contour stripping operation) shows the D11 averaged 117 L (31 gal) of diesel fuel per scheduled hour, and produced 333.3 bank m3 (436 bank cu yd) per scheduled hour (0.351 L/m3). Assuming 1 L (0.26 gal) of diesel fuel contains 10.4 kW-hr of energy, the unit expenditure of fuel energy for Case 1 Study was 3.66 kWh/m3. Another way of shifting this material is by using an overburden slusher (OS), as shown in Fig. 1. The OS as shown in Fig. I. The OS is electrically powered and consists of a manned low wall winch (LW ), a remote controlled (radio telemetry) highwall winch (HW) and a hoe. The winches operate to pull the hoe back and forth across the pit. The hoe carries load in the forward direction ahead of a rear mounted blade and returns empty. A spreadsheet (Lotus 123) simulation package, BOSSIM, models the OS operation on a load by load basis over a wide range of pit configurations. The geometry shown in Fig. 2 of the paper was modeled using BOSSI M and the results are summarized in Table1. Table 1 shows a LW with 150 kW (200 hp) and a HW of 120 kW (160 hp) installed power, towing a 15-m3 (19-cu yd) hoe, would accomplish the Case 1 stripping task at about the same scheduled stripping rate (D11=333 m3/hr or 433 cu yd/ hour, OS=342 m3/hr or 447 cu yd/ hour). It was assumed the winches in this equipment have an electromechanical efficiency of 90%. This gives an average electrical energy expenditure rate of 151 kW-hr, and a unit energy expenditure level of 0.44 kWhr/m-3(0.57 cu yd/kWh)-an improvement of 8291%- over the D11 alternative. The energy comparison illustrates the importance of using more efficient electric power if possible, ahead of the internal combustion engine, and delivering power from a fixed ground position rather than through a moving track system. Another important energy observation is the comparative action of the dozer blade and the OS hoe. The former implement continuously digs and spills as it works the load forward. The OS hoe digs the load until full, the blade then lifts due to the contained load pressure and a shear plane forms under the mass, enabling it to slide forward in a force reduced - transporting mode. Economic comparison Table 2 operating cost per scheduled hour and unit cost comparison follows a format used in Tables 2 and 3 of Hrebar's paper and compares Case 1 Study with the OS alternative. Drill and blast costs are kept constant in both cases, although when larger OS units are considered, it is expected these costs will reduce because bigger hoe sizes will permit larger rocks to be transported efficiently.

Jan 1, 1995

By M. P. Corriveau

This is the case history of how two nearby plants in Southwest Virginia solved their water clarification problems. While the solutions should not be considered applicable industry-wide, the methods used in arriving at the answers deserve consideration. When Clinchfield's Moss No. 2 Preparation Plant, the first ever built in Tiller Seam coal, was started in the fall of 1956, the clays in the raw coal soon posed a flocculation problem, Laboratory sedimentation tests were initiated; and as a result, lime was adopted as the flocculant for the clays, With lime, a pH of 11.2 was required. As the plant tonnage increased, it became evident that the amount of coal fines produced in the mining and preparation was greater than had been estimated and that the 90-foot thickener was inadequate in providing sufficient settling time to effect a clarified overflow for reuse. Testing showed that Separan 26105 (NP10)1/, when used with lime, was the most satisfactory coal flocculant available,

Jan 1, 1960

By Kenneth P. Neumann

The development of the Cyprus Thompson Creek Molybdenum Deposit near Challis, Idaho, began in 1967 when the first mining claims were staked on the intrusive rock outcrop. Exploration drilling continued for the next 14 years. During 1978, a decision was made to develop the deposit. In December, 1980, approval of the Environmental Impact Statement was received and construction of facilities and waste rock removal began. By the middle of 1983, 126 M metric tons of rock had been removed and all facilities were completed. The high work ethic of Cyprus Thompson Creek employees combined with innovation has made the mine one of the most efficient in the United States today.

Jan 1, 1983

By Phil W. Welch

At first glance, the similarity between the fine grinding of cement clinker and coarse grinding done in other mineral processing industries may seem remote. However, it is interesting to note that the mill discharge fineness of cement clinker is only 70 to 90% passing 100 mesh and quite comparable to other mineral processing grinds. There is however, a greater dependence of the mill on the air separator in the finish grinding of cement clinker than in other mineral processing industries which explains why a technique to guage the balance between a mill and separator first began in the cement industry. (1) More recently an adaptation of this technique has shown its application to the processing of phosphate rock and is the central topic of this paper. First, an explanation of work done with fine grinding cement circuits seems appropriate together with a few general comments regarding cement. When unground or partially ground cement clinker enters a finish grinding mill, it is subjected to mechanical forces of impact and attrition which gradually reduce it to a range of sizes characteristic of finish cement. That is, a range of approximately 1 to 125 microns. The large proportion of superfine particles relative to the coarse and intermediate size particles is typical of portland cement particle size distribution. It accounts for the workability characteristics of plastic concrete and the early strength development of concrete which is so necessary to its successful use as a construction material. For this reason It is quite evident from quality control tests when a shortage of superfines exists.

Jan 1, 1975

By William Crowe Kellogg

By now the term AFMAG has been fairly well introduced to the mining industry. Several papers have been presented and published concerning AFMAG (references 1 and 2). However, the term AFMAG remains rather new to the industry, and the exact place which AFMAG occupies in the minerals exploration field is still somewhat uncertain in the minds of many who may have use for this new and interesting method of electromagnetic exploration for conductive minerals. It is the purpose of this paper to again review the basic theory of the AFMAG system, to describe and - illustrate the equipment and data presentation as used in aerial surveying, and to provide some idea of the cost and nature of airborne AFMAG surveys. This paper is primarily of a general descriptive nature and presents AFMAG theory in a schematic rather than mathematical form; emphasis is placed on the equipment, the present method of data presentation and survey operations, since it is believed that such, information will now generally best serve to inform the mining industry of the characteristics of the AFMAG system.

Jan 1, 1960

By Donald Babbitt

In 1971, during the planning and design stages of a $300 million expansion, the Iron Ore Company of Canada Ltd. through its Engineers, Canadian Bechtel Ltd., came out with a preliminary request for two (2) 10,000 LTPH belt conveyor scale systems. These Systems were to provide weighing accuracies within 2.5% of the iron ore pellets and concentrates in transit on two (2) 72" wide conveyors from the stockpiles to the ships. Each conveyor system would be fed by a rail mounted bucket wheel reclaimer, with the conveyed material moving directly to the ship loaders with no inter- mediate surge and/or storage bins between the stockpiles and the ships. The bucket wheel reclaimer discharge rates would vary from 0-9600 LTPH in cyclic periods, with the periods varying from 1-5 minutes - dependent on the level of the reclaim buckets in relation to the stockpile as well as the slewing rate of the reclaimer. There would be frequent interruptions for bucket wheel repositioning (laterally and vertically), changing ship holds, and trimming ship holds. These frequent zero flow conditions, approximately 500 per 150,000 ton ship, could last 1-5 minutes. In addition, the conveyors on which the scales were to be mounted would be over the water and subject to the wind and cold of Northern Quebec. These Systems would be in use 350 working days of the year and would load 30,000,000 LT/yr. (An average of 90,000/working day).

Jan 1, 1975

By J. Jorge, J. Mariño-Salguero, B. Álvarez-Rodriguez, J. M. Menéndez-Aguado, J. J. de Felipe

"This work focuses on the characterization of heat generation during dry fracture by direct impact of a tantalum ore. Moreover, an attempt was made to quantify the heat energy loss to the environment during the grinding process of a ball mill. The study was carried out using mineral samples from a Spanish mine that were characterized by measuring their density and specific heat. During the experiments, increases of temperature ranging from 5.9 to 7.3 °C after the fracturing process were observed. A numerical model was then applied to calculate temperature distributions through the mill wall. Three possible combinations of heat transfer coefficients were analyzed, from (1) Kapakyulu and Moys, (2) Duda and (3) the heat transfer laboratory of Universitat Politècnica de Catalunya. The models with the coefficients from Kapakyulu and Moys and the heat transfer laboratory of Universitat Politècnica de Catalunya were found to provide results that were in best agreement with the experimental data. IntroductionEvery year, several billion tons of metallic ores, minerals, cement and other solids used in the ceramic and chemical industries are subjected to size reduction in ball mills around the world. The U.S. Department of Energy (2005) reported that in the United States about 29 percent of the total energy used by the mining industry, or 0.4 percent of total U.S. energy consumption, is used in comminution. In Canada and Australia, comminution is responsible for about 2 percent and 1.5 percent of total energy use, respectively. In nonindustrialized countries where mining constitutes higher fractions of their industrial sectors, comminution costs represent a significant contribution to mine operating costs. The specific energy consumption values for the grinding of these materials typically range from 5 to 50 kWh/t. Thus, a significant amount of electrical energy is consumed in the ball mill grinding operation (Aguado et al., 2006; Gupta and Sharma, 2014). Grinding can represent up to 50 percent of the direct operating cost in a mineral processing plant, especially as comminution devices operate in highly inefficient ranges of 4 to 8 percent (Wang, Yang and Yu, 2012)."

Jan 1, 2017

By Kyoosang Yoo

The report presents the results corresponding to the analysis of a lining system for tunnels in soil and soft rock in creep-active ground. The purpose of the analysis is to evaluate the performance of a lining at each construction stage. The steps include: 1. Accurate representation of the initial undisturbed state of stress 2. Excavation, 3. Lining installation 4. Injection of mortar and its curing, and 5. Short-, medium- and long-term creep behaviour in the surrounding soil/rock. The response of a prototype tunnel is simulated using the computational finite element framework MSC.marc2008.

Jan 1, 2010

By D. D. Rabb

Originally, the term solution mining applied to a dissolution, washing, or "brining" of soluble salts such as halite (common table salt), potash or trona. After the mid-sixties, however, the definition has been expanded to include heap and dump leaching, in-place (in situ) leaching, removal of oil from tar sands, extraction of sulfur from deep wells by the Frasch process and the recovery of metalliferous solutions from geothermal sources. Solution mining is also known as borehole, non-shaft, or chemical mining; the extraction of soluble mineral values from a variety of ores using appropriate solvents and chemicals. Solution mining frequently involves chemical changes; for example, copper usually goes into solution as copper sulfate, gold and silver as a cyanide compound, and uranium as a sulfate or uranyl tricarbonate. The valuable constituent is removed from the solid body of the ore by mass transfer to a aqueous solution.

Jan 1, 1986

By E. Jackson

This paper describes highlights of the Placer Dome MiniMole project - the development and testing of a robotic machine for mining narrow ore veins. A prototype hydraulically controlled robotic machine was built and tested. The machine provided a platform for testing numerous cutters in the field. Other cutters, e.g. undercutting devices, were tested in the lab. Extensive analyses were done on specific energies and cutter penetration. Three sets of quarry trials were done, then the machine was tested in an underground mine. Rock UCS values varied from 180 MPa to 230 MPa. The paper includes lessons learned and recommendations based on the project findings.

Jan 1, 2007

By Mengxiong Guo, Xuxin Shao

The recent depressant research is summarized, and a new kind of depressant (SCO) has been put forward in this article. Using Na-oleate as a collector and SCO as a depressant, separation of dolomite and phosphate was studied. When SCO was added in the concentration range of 80 g/t to 2kg/t at pH 9.5 ± 0.2, dolomite was absolutely depressed, and apatite kept its floatability. Interestingly, in the mixture of phosphate and dolomite, the dolomite floated. The reasons for such a behavior are investigated through flotation and electrokinetic studies. It was found that the adsorption of dissolved species on dolomite and phosphate resulted in reverse flotation. A concentration of 31.59% P205 and 83.87% recovery of P205 was obtained from the mixture of phosphate and dolomite (2:1) with 26.6% P205 using 210 g/t SCO and Na-oleate 4.93*10-5 M at pH 9.

Jan 1, 1989

By Rodrigo Estay Huidobro, Andrés Martinoli, Claudia Pavez-Orrego

The effects of induced seismicity caused by mining activities are one of the main problems that the mining industry faces. Although it has been documented by countries with a great mining tradition (United States, Canada, Australia and Chile) for over a century, the problem has been intensified throughout the years due to the greater depths that mineral extraction reaches, where the stress levels and environmental conditions increase the possibility of a rockburst occurrence. Seismic events inside the mine cause important losses of human lives and infrastructure damage. To deal with this problem it is necessary to implement several kinds of safety protocols. For example, seismic indicators allow to identify, through the analysis of a set of seismic parameters -magnitude, energy, time, decay rate, among others-, periods of time when a seismic event of considerable magnitude is most likely to occur. The objective of this work is to use the frictional energy generated by a microearthquake inside the mine as a seismic indicator, linking it with the occurrence of large magnitude seismic events which are outer the background activity. Thus, we seek to determine the set of seismic parameters which allow the best performance of the frictional energy/heat indicator. In the present study, we considered magnitude, frictional energy, and time as seismic parameters to study the efficiency of the proposed indicator. The optimal set of parameters was determined using two different methodologies: accumulated thermal energy and alert bands. The Piece Skill Score and the Accuracy indexes were used to evaluate each set of parameters. Both approaches show a high rate of true positive and true negative hits. Furthermore, it was concluded that both methods show complementary results in terms of the detection of critical events (Mw > 3.0).

Apr 26, 2022

By O. E. Wheeler

The use of the walking dragline as a stripping tool has increased dramatically in the past two decades. The reasons for its increased popularity and some historical background on its introduction into the mines are given in a recent paper by Learmont. (l)* The history need not be recounted here except to show the trend to longer booms which has accompanied the growth in machine size. Figure 1 shows the change in maximum operating radius on Bucyrus-Erie machines which has occurred over the years and Figure 2 shows the corresponding change in maximum boom lengths. Reference 1 also presents some of the reasons for expecting this trend to longer booms to continue. There are many design parameters affected by the increase in boom lengths; swing power, hoist and drag rope lengths, and drum capacity, to list just a few. The purpose of this paper is to discuss only the structural implications of using longer booms. As in the design of any structure, the various facets of boom design are interrelated and a process of optimization between them must be worked out either by evolution or by conscious iterative effort. The decisions we have reached about such things as material selection, structural arrangement, and applicable criteria, have not come into being overnight but represent instead many years of design experience and a fair amount of recent concentrated analytical effort. In the following pages an attempt will be made to first, state those decisions, second, explain how we arrived at that particular result; and third, describe what we expect future developments to be which might influence us to change those decisions.

Jan 1, 1976