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By Takashi Sasaoka, Hiroshi Takamoto, Akihiro Hamanaka, Pongpanya Phnthoudeth, Hideki Shimada, Jiro Oya

"Indonesia is the second largest coal exporter to Japan, accounting for about 30 Mt annually. They produced over 400 Mt in 2015, over 99% of which is from open-cut mines. However, the conditions of surface mining are becoming worse year by year: the stripping ratio is increasing, the economy is worsening, and the infrastructure for coal transportation from inland mining areas is not being maintained. To meet the demand for coal in Indonesia and the rest of the world, underground mines have to be developed. In consideration of growing need, our research program is conducting a study on the potential for an underground coal mine in Indonesia. This research is being done through the roadway heading research program, which is looking into developing an underground coal mine from an open pit highwall. The greatest challenge for underground coal mine development in Indonesia is the maintaining the safety of the mine roadway during heading because the roof rock is exceptionally weaker. There is a potential for heading below mobile, unconsolidated soft sediment, and instead mining a deep area. This increases the likelihood for problems in the stability of the support system due to increasing ground pressure. The ground behavior around the roadway was measured using telltales, extensometers, and convergence measurements. Moreover, rock property tests were also conducted on exploration drilling cores. Based on the geological dates and monitoring data, a series of numerical analyses were conducted in order to assess support needs in the main roadway under different depths. Results of numerical analyses indicate that the current arch support design is effective when the mining depth is lower than 100m. However, if the mining depth is larger than 100m, the current arch support design should be changed to include the application of higher yield strength material, shorter spacing, etc. Moreover, bolting may also be useful if ground pressure is high locally. Based on a series of measurement data of ground and support behavior, a control criterion for main roadways under weak geological conditions is proposed in this paper."

Jan 1, 2017

The London Metal Exchange began its first official session of aluminum trading on Monday, October 2, LME prices based on 3-month forward contracts opened Monday at 52.4 cents per pound, fell midway through the week to 52.3 cents and ended Friday at a high of 52.7 cents. For the week, LME metal averaged 52.5 cents. Although Reynolds Metals Co. and Aluminum Co. of American continued in September to value unalloyed 99.5 percent aluminum ingot at 53 cents per pound, other producers were at higher positions of 55-57 cents. Alcan Aluminum Corp. of Alcan Aluminum, Ltd., a Canadian producer, increased prices for its U.S.-marketed ingot by 2 cents to 55 cents per pound, effective September 21. New York merchants increased ingot quotes by approximately 0.5 cents to 52.8-53.5 cents per pound.

Jan 1, 1978

By A Palynchuk

The development of welded pipe has paralleled the general industrial development and, in particular, that of the petroleum industry. The petroleum industry's need for high-grade, economical pipeline material to make many 'of its projects feasible has been a significant factor in the development of light-wall, high-grade welded pipe. The modern welding processes, such as high-frequency, electric resistance, flash, submerged arc, etc., have some basically different characteristics. The modern high-frequency weld mill is a complex of specialized equipment that is integrated into a production unit. Each component in the unit performs a specific function in the production process. Quality control must be built into the process on an operating basis and, to maintain the quality required for pipeline standards, must be more than a policing operation. The further development of the welded pipe industry will be determined by changing and increasing demands. The technical and economic views and requirements that will influence the development have to be resolved.

Jan 1, 1964

By H. M. Lizama, R. L. Stephens

Secondary leaching of previously leached supergene copper ore has been developed and implemented at Teck’s Quebrada Blanca operations. This consists of using in-situ leaching techniques aided by geophysics to recover the residual metal value from dormant copper leaching heaps. These heaps of crushed and agglomerated ore had been leached 20 years previously but still contained significant copper values. The concept was first tested on a 3,200 m² sector, where injection wells introduced leaching solution into a production zone and electro-resistivity tomography was used to track solution movement within. Operating parameters such as well spacing and injection flow rates were determined. Copper recovery and leaching performance were evaluated based on solution and metallurgical balances. Both ferric leaching and bacterial leaching were enhanced through strategies to pull air into the heap. Positive results from the initial test prompted a larger, industrial pilot test on a 60,000 m² area and 97 injection wells. This larger test obtained a copper recovery of 30% in 457 days. Secondary recovery is now being implemented to all of the abandoned heaps at Quebrada Blanca and has become a production stream. This technology has the potential of wide application to mature copper heap leach operations, and Teck has patented the process and associated methodologies. INTRODUCTION Heap leaching of copper secondary sulphides has been carried out at Quebrada Blanca (QB) since 1994. Ore from the supergene deposit was crushed and agglomerated prior to leaching. Originally, the ore was leached in 6 m lifts stacked one on top of another, known as a static pad configuration. However, in 1998, after the second lift, the operation changed to a dynamic pad configuration; the ore was leached in a single lift and the resulting residues were removed to make way for fresh ore (Yáñez, Ahlborn, & Ramos, 2007). The first two static lifts were left in place and served as a foundation for the dynamic lifts above. Those two buried lifts of leached residues, some 16.8 million tonnes and covering an area of approximately 0.71 million m², remained buried under the dynamic pad.

Jan 1, 2019

By A. S. Usmani

The flow associated with the pouring of molten metal into moulds has been modelled on the basis of certain simplifying assumptions. A finite element based Navier-Stokes equation solver has been used to analyse the flow. The velocities obtained from the Navier-Stokes equation solver are used to advect a pseudo-concentration function for modelling the fluid front. A simple problem with a known analytical solution is solved first to test the model. Subsequently, several more examples with varied geometrical configurations are modelled, including one with curved flow boundaries.

Jan 1, 1992

With unprecedented worldwide growth and increasing global demand for energy expected to swell by 60 per-cent in the next two decades, mining matters as much now, if not more, than it ever has. This was the consensus at the 110th Annual National Western Mining Conference presented by the Colorado Mining Association, Feb. 12-14 at the Westin Hotel in Denver, CO. The role of coal ? America?s most abundant energy source ? the future of uranium and its possible resurgence in the energy marketplace, the skyrocketing value of gold as well as the issues of health, safety, climate change, legislation and government?s role in mining were all discussed during the three-day conference that operated under the banner of ?Mining Matters.? Barbara Filas, chairperson of the 110th National Western Mining Conference, president of Knight Piesold Co. and former SME president, welcomed the record crowd with an inspiring speech in which she pointed out that although ?most normal folks don?t know what role mining plays in their everyday life, mining does matter. ?Our industry,? she said, ?matters to Colorado. It matters to Colorado because it is a $3-billion industry. It matters to the 13,000 people who are employed directly or indirectly by the industry and it matters to schools that receive more than half of the royalties that are generated by mining.? During discussions of mining?s place in Colorado, the western United States and the world, special attention was paid to coal, uranium and the future of energy. ?It is time to rethink our perceptions about coal,? said Mark A. Smith, president and chief executive officer of Chevron Mining Inc. He spoke during the opening reception in a presentation titled, ?Coal to Liquids: Bridging America?s Energy Gap.? Although coal is America?s most abundant, and cheapest energy source, it is also one of the most scrutinized because of the pollution it causes and recent, and heavily publicized, tragedies that have claimed the lives of some who mine it.

Jan 1, 2008

By R. G. Zaripova, N. D. Ryan, H. J. McQueen

The austenitic and ferritic stainless steels do not undergo any phase transformation that induces very fine grains in the product through thermomechanical processing as practiced in most other steels. Considerable grain refinement can be achieved by intense multistage deformation descending through warm to cold working; notably multi-axial forging of bulk material can attain high strains with diminished risk of cracking. Hot working to improve ductility yields finer grain sizes as the T is reduced and strain rate E raised; increased strain has limited effect due to the steady state regime. Ferritic steels develop subgrains with size diminishing as E rises and T falls with the advantage of retained strain hardening; recrystallization delivers grains several times the cell size. In austenitic steels, dynamic recrystallization (DRX) provides finer grains at higher E and lower T with a lower limit due to intergranular cracking. The DRX grains contain a strengthening substructure that can easily be retained by quenching; if static recrystallization is allowed to occur the grain size rises markedly. Multistage rolling with diminishing T is able to provide grain refinement to the same degree as straining at the finishing T yet provides better ductility. grains on recrystallization. As a result of the strain induced transformation to martensite, small subzero deformations of austenitic or duplex steels produce very high dislocation densities that yield marked grain refinement when they revert upon reheating.

Jan 1, 2004

By W Taylor, S Chen, R Haywood, M White, R West, J Ranasinghe

In March 2012 a combined BHP Billiton and Hatch team embarked on a program to improve the concentrate burner efficiency of BHP Billiton’s Olympic Dam copper flash smelting furnace. A multi-faceted approach including an analysis of the furnace using operational knowledge and first principles engineering led to the design and supply of a new central-lance (disperser). A new, patented, swirl method of introducing the copper concentrate into the furnace was developed to integrate with the existing concentrate burner. Plant trials in 2014 demonstrated an increase of nearly 10 percent in the oxygen efficiency of the furnace. The improved efficiency is expected to provide savings in operating costs and asset life extension of downstream gas and dust handling equipment.CITATION:White, M, Haywood, R, Taylor, W, Chen, S, Ranasinghe, J and West, R, 2015. Improved copper flash smelting at Olympic Dam, in Proceedings MetPlant 2015, pp 382–395 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By J. M. Elder, W. S. Kow

Challenges to new heavy mineral deposit developments are presented. These include land use issues, particle fineness, declining grades, and particle coating, amongst others. Industry responses to these are presented as possible solutions.

Jan 1, 2005

By Alfred Petrick

This study gives an analysis of the copper system byproducts and discusses the identification and classification of byproduct metals and their supply systems. Arsenic, platinum-group metals, silver, gold, selenium, tellurium, molybdenum, rhenium, uranium, aluminum, magnesium, and byproduct copper, lead, and zinc from complex ores are covered. The report describes several metallurgical systems, the marginal and incremental products costs of byproduct subsystems, industry structure and organization, and the historical data on price, consumption, and supply. Supply curves are presented for about one-half of the byproduct metals studied. The study develops a conceptual framework for analysis by reviewing the present concepts of byproduct supply and the related price theory. It gives the sources of supply of the individual byproduct metals to indicate the importance of the byproduct supply to the total supply. Mills, smelters, and refineries processing byproduct materials for their metal content are identified by geographic location and company ownership, The study also includes information on the reserves-resource base supporting byproduct output, reserve estimates, and the demand aspects of each byproduct metal.

Jan 1, 1973

By Jerry C. Tien

In 2009 China mined 2.695 billion metric tones (Gt) of raw coal. It is estimated that only 3-5% or roughly 135 million metric tones (Mt) of these were mined from 300 some surface operations. Except for a dozen or so large modern operations, most of China's surface coal operations are small by western standards, with annual production ranging from a few thousand tones to 300,000 metric tones (mt). Depending on the size of operations, equipment used range from small trucks and shovels to large bucket wheel excavators and draglines in sizable pits. This article provides a brief overview of China's surface mineable coal reserves, mining methods commonly used and increasing environmental concerns; introductions of several large surface operations are also provided.

Jan 1, 2012

By A. B. Hooker, E. J. Coggeshall

"Dry cells are modified wet primary cells in which the electrolyte is held by absorbent material so that it does not spill aid the cell jars are sealed to prevent evaporation of the absorbed electrolyte. Most dry cells in commercial use are modifications of the Leclanche wet cell. In their usual form they have a hollow cylindrical zinc negative pole that constitutes the containing vessel. An absorbent material, either as a lining in the zinc jar or a bag, separates the zinc cylinder and a rod or flat plate of carbon placed axially inside. A mixture of crushed coke, graphite, and manganese dioxide is tamped about the carbon rod, and the whole mass is saturated with salaanoniac-zinc chloride solution.Dry cells are suitable for services that require minute currents continuously or larger, though limited, amounts of current intermittently. Though limited in this way, they have a wide use, even in underground mining. This paper details some of the applications of dry cells in mines, particularly from the standpoint of greater safety through their use.APPLICATIONSThere are four fields of application of dry cells to mining: (1) Electric shot firing; (2) auxiliary lighting; (3) signaling; and (4) testing.SHOT FIRINGFiring an electric detonator requires very little electrical energy because although the current flow may be 1 to 3 amperes the duration of flow is so small (1 to 4 milliseconds) that the energy withdrawal per shot is almost negligible. Batteries for shot firing need not be large; they may be used for firing either single or multiple shots."

May 1, 1934

By Reinhardt Thiessen

Views and conceptions of the origin, composition, and general nature of coal differ so widely that to determine the real extent of actual knowledge is no easy matter. The chemist finds difficulty in attacking the chemical problems and the engineer lacks a broad chemical basis for the study of his problems. Thus the economical and efficient utilization of coal in the industries suffers from a lack of knowledge of the composition of coal itself. Most scientists interested in this matter, as has been brought out in discussions during the recent investigation of coal problems, appear to have only a vague idea of the components of coal and their origin. Some are even in doubt as to whether substances derived from the wood and resins of plants form a part of coal; and few seem to have more than the dimmest idea of what are the components of coal, the condition in which these now exist, and the transformations that they haye undergone. Although during the paiilt century or more many co.rrect observations have been made and recorded, these were falsely or inadequately interpreted, so that many of the interpretations rendered are contradictory. As a result there has been great confusion. Many of the observations made in the past, although accurate and correct, could not be explained, because the principles involved in a correct solution of the problem were not then known. For example, Parkinson, Hutton, Petzhold, Guembel, and others made valuable discoveries regarding the processes by which plant substances are transformed into coal, but as the principles involved are those of colloidal chemistry, a science not known to the scientific world of that time, the observed facts could not be interpreted and the solution of the whole problem was blocked. The explanation of the true meaning of the alternating bright and dull bands so familiar in all ordinary bituminous coals afforCls another example. This banding has been observed and recorded from the earliest times, and has led to the forming of many false theories. Some gAologists, for example, have endeavored to explain the bands as due to alternating climatic conditions during the coal-forming period. Had the geologists known the true nature of coal they could not have made this mistake nor many others made in the past. To fill in a few of these gaps and to clarify some of the existing confusion is the aim of this paper. The immediate cause that led the author to investigate further the composition of coal and the origin and structure of its constituents was that when an attempt was made to discover the meaning of the coking and noncoking properties of coal a more exact knowledge of the nature of coal was required than was then available.

Jan 1, 1920

By A. A. Sadegh

A laboratory investigation was carried out on the characterization and beneficiation of sillimanite ore. Petrographic analysis indicated that the ore consisted of massive elongated sillimanite grains in a matrix of hematite, garnet, feldspar and silica. A procedure for estimating the percentage of sillimanite was developed using float-sink and magnetic-separation techniques. A liberation study was carried out to determine the level of size reduction required to achieve sufficient liberation while ensuring that gravity concentration techniques would be applicable. Laboratory testing was performed on the liberated ore to investigate the applicability of using wide-angle dense-medium cycloning to upgrade this ore. Initially, medium-only tests were carried out using various size distributions of magnetite and ferrosilicon as the dense-medium solids to evaluate the effects of operating conditions on medium segregation. Depending on the medium solids and operating conditions, either positive of negative differentials (difference between the relative densities of the underflow and overflow streams) were obtained. Based on these results, separation tests were performed to process nominal -1.2-mm sillimanite ore. The results indicated that sillimanite concentration could be obtained using a medium relative density that was much lower than would typically be used in a dense-medium cyclone separation.

Jan 1, 2007

By H. W. Gillett

This bulletin is issued by the Bureau of Mines as a contribution to the increase of safety and efficiency in the preparation and utilization of the mineral resources in the United States. Notable among the drains on these resources are the demands made by the nonferrousmetal industries, and in these the losses occasioned in melting brass and bronze are worthy of particular attention. This statement will be better appreciated by a consideration of the size of the brass industry. MAGNITUDE OF THE BRASS INDUSTRY. According to the Thirteenth Census, in 1909 there were in the United States 1,021 fu-ms that dealt mainly in brass and bronze. This total included jobbing foundries, manufacturing plants that both cast and machine a brass or bronze product, and rolling mills, but did not include iron foundries having nonferrous departments nor the numerous large brass-foundry departments of manufacturing plants that produce the castings used in the manufacture of electrical apparatus, cash registers, pumps, and the thousands of machines that require brass castings for their construction. Penton's Foundry List for 1910 gives about 1,150 exclusively nonferrous foundries and about 2,300 iron or steel foundries that also melt brass. If the rolling mills and. jobbing foundries in manufacturing plants be included, and if due credit be given to the rapid growth of the industry in the last few years, largely through the stimulation of the automobile busi¬ness, it is probable that not less than 3,600 plants are to-day melting brass or bronze.

Jan 1, 1916

By H. G. Stephenson, D. Castendyk

Open pit anthracite mining at the Canmore Creek Mines, Canmore, Alberta, south of Banff National Park, resulted in several pit lakes by the early 1970’s. To enable future mining opportunities in the Rocky Mountains, operators decided to reclaim the site into a non-polluting landscape which would provide a memorable outdoor experience for residents and visitors alike, and would preserve wildlife habitat. Reclamation began with the stabilization and revegetation of spoil piles adjacent to Canmore Creek, and the backfilling and revegetation of Canmore Creek Mines No. 1 and 2 to create “Salamander Pond.” The company dammed the outlet of an open pit at Canmore Creek Mine No. 3 to raise the water level and create Quarry Lake. Reclamation concluded in 1980 when the Town of Canmore took ownership. Quarry Lake is now the centerpiece of 293-acre Quarry Lake Heritage Park, a popular destination for swimming, hiking, and fishing, visited by about 400 people on summer days. The Alberta Environment Conservation Authority described this as “The best mine reclamation in Western Canada.” Quarry Lake is an exceptional example of walk-away, pit lake closure, where the mining company created a valued post-mining asset and was released from future liabilities. INTRODUCTION One of the most important environmental issues associated with contemporary open pit mining is the closure of mine pit lakes, and the perpetual legacy these lakes can potentially generate. Ideally, successful pit lake closure includes the following: (i) the water quality within the pit lake, plus surface water and groundwater discharging from the pit lake, meets pre-mining, or other acceptable water quality conditions of the receiving environment, (ii) the termination of all active treatment processes, (iii) the return of the pit lake to the government for long-term care and maintenance, (iv) the release of the mining company from all future liabilities associated with the pit lake, (v) the return the environmental bond to the mining company, and (vi) the reuse of the pit lake for some post-closure, beneficial purpose. The achievement of these goals is known as “walk away, pit lake closure.” Peer-reviewed, publications of successful walk away, pit lake closure provide mining companies the ability to address public concerns regarding the safety of pit lakes which commonly occur during the permitting, operations, and closure phases of mining. To date, most published work on walk away, pit lake closure work has occurred in the coal mining sector in Germany and Australia (McCullough et al., 2009; Jones and McCullough, 2011; Kumar et al., 2013; Schultz et al., 2013). However, in North America, examples of walk away, pit lake closure are not widely discussed in the literature despite there being excellent examples from the coal mining sector in Alberta, Canada (e.g. Pleasure Island, Black Diamond, East Pit, Sphynx, Robb, Lovette, Siltstone, and Sterling), and from the iron mining sector in Minnesota in the United States (e.g. Portsmouth Lake, see MNDNR, 2018). Although seldom included in discussions of pit lakes from the metal and coal mining sectors, the aggregate and fabricated-stone mining sectors also produce pit lakes, and there are numerous examples throughout North America where these pit lakes have been successfully closed and transformed into post-mining resources. The difficulty of finding these good examples in the literature makes it challenging for companies to respond to public and regulatory questions regarding pit lake closure and reuse. As such, there is a pressing need document the motivations and approaches used in examples of successful, walk away, pit lake closure in North America so that the mining industry at large can learn from these examples and can better address public concerns.

Jan 1, 2019

By Alan M. Jessop

This paper discusses the distribution of frozen ground in the zone of discontinuous permafrost in relation to the pattern of surface temperature. The importance of understanding permafrost in relation to surface construction and open-pit mining operations is stressed.

Jan 1, 1972

By M. W. Airth

ON THE 6TH JULY in the year 1953 an announcement was made to the public that touched off one of the greatest staking rushes in the history of mining in Canada and resulted, in tl1e space of a few short years, in the development of the greatest reserves of uranium-bearing ore in the world. It was ?On this date that the famous "Blind River back-door staking bee" was completed with the acquisition of some 2,000 claims by the Preston East Do me-Technical Mine Consultant teams under the direction of Mr. Franc Joubin and Mr. Robert C. Hart. That story has been told from coast to Coast and is too well known now to re-quire elaboration. Suffice to say that, in the short elapsed time of less tl1an five years from that momentous summer of 1953, three of the Algoma mines are in full production, three more are rapidly nearing full production, five more 1are approaching the production stage, a new hard-surfaced highway, 108, has been built to serve the area, and a brand new, completely planned city, Elliot Lake, is being built to provide the amenities of living to the 22,000 people already in the area.

Jan 1, 1958

By William D. Macdonald

The Upper Devonian Kettle Point black shale of southern Ontario is poorly exposed. Structural maps pre-pared from the data of numerous wells show that the upper surface of the formation has low regular relief, and that the lower surface reflects domes in the Middle Devonian and also local subsidence of the Devonian rocks due to solution of salt in the Silurian Salina Formation. The appearance of minor amounts. of marcasite, pyrite, and calcite, m that order, as interpreted from the evidence of concretions from the type locality at Kettle Point is thought to have been influenced by a rise m the pH within anaerobic sediments preceding compaction.

Jan 1, 1960

By N. Vayenas, G. Yuriy

"The combination of a predictive reliability assessment model and discrete-event simulation can be an effective methodology to study the impact of equipment failures on the capacity of production systems in mines. In our case, a predictive reliability assessment model using genetic algorithms is combined with a discrete-event simulation model to analyze mine equipment systems.Discrete-event simulation involves modelling of real-life systems based on variables and events that occur or change at distinct points in time. The Simul8 simulation software, by Visual Thinking, is used in this research. It is a two-dimensional (2D), discrete-event simulation/ animation software tool for creating realistic depictions of manufacturing and materials handling systems.The simulation model developed for the purpose of this research represents a typical two-level, sub-level stoping section of an underground mine in the Sudbury region in Ontario, Canada. This 2D model was created to assess the impact of equipment failures to a mine’s production throughput. In more detail, using mean time between failures (MTBF) data of scooptrams derived from a reliability assessment model based on genetic algorithms, LHD failures are incorporated into the simulation model. These failures cause production interruptions to the development cycle and consequently loss of hauling capacity.Another purpose of this research work is to demonstrate how low-cost simulation tools such as Simul8 can be successfully applied to model underground hard rock mining operations. The research discussed in this paper is carried out by the Laurentian University Mining Automation Laboratory (LUMAL)."

Jan 1, 2005