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By Boris Arlyuk

The system of short term forecast of metal prices at LME is based on correlation between prices within the quarter forward and at the first place by economic parameters at the West, determining the consumption of metals. Such economic parameters are presented by data of indexes of Western World industrial production (WW IP), official data of IP and Dow Jones indexes at USA. For price forecast within the quarter forward (one day ahead, 3 day -65 days MA forward prices) are significant the changes of actual prices (official and close) at the past and the parameters of daily trade at LME at the past (futures turnover, open interest, LME stocks). It is developed subsystem of price forecast within the quarter forward based on analytical approach determining the relations between the participants of the market. It gives the opportunity to reduce the number of empirical coefficients at the model and receive good accuracy of forecast the MA prices and its direction at the future. Very important part of short term forecast is subsystem determining analytically the probability that the price forecasted for the next trading day will be the maximum or minimum daily price within the quarter forward. The thresholds probabilities are defined by identification the model at the past by maximal commercial efficiency. Such system was tested at the past at period since 2000 till 2005 and gives very high commercial results at operations on 1M forwards and hedging the sales of nonferrous metals traded at LME (primary aluminium, light alloys, nickel, copper, zinc, lead and tin).

Jan 1, 2006

An integrated computer system (the Short Term Mine Management System) has recently been developed by B.H.P. Steel Long Products Division in Whyalla, South Australia for use in their open pit iron ore mines.The system incorporates blast design, comprehensive blasthole data handling, grade coilrol, stockpile scheduling and management and reconciliation within a single, user friendly computer package. The blast design system allows the blasting engineer to design the layout of holes for a production blast using geological information projected from the bench above to aid in appropriate blasthole positioniog in particular rock types. The grade control system allows mining blocks to be designed and evaluated from blasthole information using interactive graphics processes. The handling, storage and reporting of blasthole survey, assay and geological logging data forms an integral part of this system. Stockpiles can be constructed from a number of mining blocks to reach a specified target grade using the stockpile management system. Although not yet integrated, the reconciliation system will reconcile stockpiles back to mining blocks and to the geological model.

Jan 1, 1990

By P. Brumit, L. Grady, R. Mitts, V. Holm

The Mesquite mine is a large, open pit, heap leach gold mine owned and operated by Gold Fields Operating Co.-Mesquite. The mine uses a fully integrated mine planning and reserve modeling software system developed at the mine. This system has recently been extended to include short-term mine planning, grade control, and daily production reporting. The grade control portion of the program uses a multiple indicator kriging (MIK) approach using the blast-hole spacing and exploration assays. The program permits ore control geologists and mine planning engineers to have immediate access to all the information.

Jan 1, 1991

The Mesquite mine is being operated by Gold Fields Operating Co.-Mesquite, a subsidiary of Gold Fields Mining Corp. The mine Is located in southeastern California about 56 km (35 miles) east of the farming community of Brawley, California. The mine has been in commercial production since early 1986 and Is a conventional open pit mine developed on 6.1 m (20 foot) benches. The gold is recovered by heap leach using permanent heaps built in multiple 6.1 m (20 foot) lifts. This year's gold production will be in the range of 5,600 kg (180,000 troy ounces). Current ore production is about 18,140 tonnes (20,000 tons) per day while the total tons mined Is averaging 65,000 tonnes (72,000 tons) per day. The climate at the mine is extremely arid with rainfall of 7.6 cm (3 inches) per year. From early May until late October daytime temperatures generally exceed 37.8 degrees Celsius (100 degrees Fahrenheit) and can be as high as 37.9 degrees Celsius (120 degrees Fahrenheit).

Jan 1, 1989

By R. W. Barbaro

The limitation of sulfur dioxide in power plant emissions dictates that sulfur in coal be reduced to the lowest possible level before combustion so as not to aggravate the emission control problem at the stack. For coal fired power plants, the methods in practice to achieve low sulfur coal include mining areas with relatively low sulfur. reducing sulfur in the mined coal through preparation techniques and blending high and low sulfur coals. A prerequisite to the successful implementation of any of these practices is the knowledge of the spatial distribution and the capability to predict sulfur values in a coal seam.

Jan 1, 1988

By Kenneth S. Graham, S. C. Gambrell

A short term, simple roof bolt load cell which uses a birefringent (photoelastic) coating as its sensing element has been developed. The load cell is installed between the bearing plate and the nut/washer and measures the initial force after installation by the bolting machine. The load cell can be removed from the bolt and used again to measure initial force in another bolt if desired. Because temperature and humidity changes in the mine cause creep/relaxation of the coating and/or adhesive, the load cell is useful for accurately measuring force for a period of only two weeks after installation. Force in the bolt is determined by referring to a calibration curve for the load cell.

Jan 1, 1992

By Michael Gilbert

In the world of tunneling the glamour is in the large diameter, long tunnels, but perhaps the number of projects for small diameter and short length tunnels are greater and generally have higher risk factors. Reasons for these higher risks include both the ?boiler plate? contract provisions used on these types of contracts, the technical specifications related to the tunnel work (versus the pipeline construction), the bid practices including measurement and payment and the construction. This paper reviews and comments on some of the key issues the authors have observed in recent major pipe-line projects that involve a small percentage of tunneling footage of the total contract.

By David Smith

Construction of a new transportation link frequently requires crossing under an existing highway or railroad. Although traffic diversions may permit a cut and cover structure to be built, ‘zero impact’ tunnel solutions are becoming increasingly popular. The vertical clearance between the new tunnel structure and the existing highway or tracks may be very low; sometimes less than two meters. This leaves little room for error since any ground loss can rapidly translate into surface settlement. Problems can be avoided by maintaining the stability of the tunnel face and by minimizing ground movement around the tunnel lining. This paper examines construction methods that have been used to construct short tunnels with shallow cover, and highlights factors to be considered for future projects.

Jan 1, 2005

By S. V. Lukichev, O. V. Nagovitsyn, V. V. Laptev

In this paper the authors describe the developed algorithms of short- and medium-term planning of underground mining operations. The algorithms were developed using the example of the flat-back cut-and-fill method, and provide multifactor accounting of mining conditions, technical and technological limitations: state and properties of the rock mass; the current mining situation; mining rules; availability of safety pillars; properties of the filling; additional characteristics of technological objects that complicate the driving of workings; sufficiency of human and technical resources; employee specialisation; existing machinery and equipment; opportunities and limitations of the transport scheme of the mine, and work schedule. The paper is presented by means of a dynamic model of mining development, which shows the sequence of mining operations in the mine workings. Besides animation, the tool provides an opportunity to form tabular and graphical reports.

Sep 1, 2021

By Lewis L. Oriard

The authors outline the development and application of blasting methods put into use 11 years ago at the Berkeley Open-Pit Mine, Butte, Montana. The blast design uses a very short delay (5 milliseconds) between detonation of explosives charges, a feature challenged several times in principle despite its success for Anaconda. Concern is expressed over the categorical rejection of very short delay blasting which can make the difference between success and failure of major mining operations. There is ample evidence to show that the method can be used successfully and not violate the concerns of the public.

Jan 1, 1980

By Stephen C. Tadolini, Steve Bessinger, James Pile, Christopher Mark

The San Juan Coal Mine, located near Farmington, New Mexico, supplies the San Juan Generating Station with more than 6 million tons of coal annually. To replace dwindling surface mine production, San Juan installed a longwall in 2002. The roof rock in much of the underground reserve consists of interbedded coals, carbonaceous shales, and mudstones. Roof support consists of fully-grouted roof bolts, both tensioned and non-tensioned, supplemented by modified cable trusses. Short-encapsulation pull tests conducted by San Juan’s geotechnical engineering department showed that some of the immediate roof layers provided variable bolt anchorage. To ensure that the roof bolts were obtaining the necessary anchorage, additional tests were conducted in a variety of locations. The results have been used to determine the optimum support design for different areas of the mine. Another series of tests evaluated the performance of several bolt and hole diameter combinations. The experience at San Juan Mine shows that short-encapsulation pull tests can provide the information necessary to improve ground control in variable roof conditions. It also illustrates how a pro-active geotechnical engineering program can be an essential component of a state of the art underground coal mine.

By James Pile

The San Juan Coal Mine, located near Farmington, New Mexico, supplies the San Juan Generating Station with more than 6 million tons of coal annually. To replace dwindling surface mine production, San Juan installed a longwall in 2002. The roof rock in much of the underground reserve consists of interbedded coals, carbonaceous shales, and mudstones. Roof support consists of fully-grouted roof bolts, both tensioned and non-tensioned, supplemented by modified cable trusses. Short-encapsulation pull tests conducted by San Juan's geotechnical engineering department showed that some of the immediate roof layers provided variable bolt anchorage. To ensure that the roof bolts were obtaining the necessary anchorage, additional tests were conducted in a variety of locations. The results have been used to determine the optimum support design for different areas of the mine. Another series of tests evaluated the performance of several bolt and hole diameter combinations. The experience at San Juan Mine shows that short-encapsulation pull tests can provide the information necessary to improve ground control in variable roof conditions. It also illustrates how a pro¬active geotechnical engineering program can be an essential component of a state of the art underground coal mine.

Jan 1, 2003

By B. M. Flohr

Railroads are cost competitive with trucks for hauls greater than 500 miles - WRONG. Today I will tell you about many rail movements of less than 100 miles throughout the country. Rail is a short haul transportation alternative you must consider. Transportation today is the largest controllable cost in the total cost of production of goods. In fact it is the one cost area where aggressive management, using new tools, can achieve significant reductions. You can't control the price of metals in the world market, you can't control labor rates since they are tied to industry norms, and the price of raw materials are relatively insensitive to specific price reductions to your firm. Transportation is the one area where major savings are now being realized. Sample Movements First, I will give you several examples of short haul rail moves to make you a believer that they do exist. Then I will show you the reasons why railroads suddenly "like" short hauls.

Jan 1, 1986

By J. Schleifer

On short term, planning techniques require more details to ensure feasibility, giving importance to operation constraints and use of available resources. In GUEMASSA (Morocco), the ore mass is mined by cut-and- fill method. Correct organization requires to forecast a few weeks ahead the schedule of blocks to be mined, in order to respect ore quantity and grade constraints. While operating constraints are tackled, feasibility is assumed with an average production capacity suggesting that resources will be available. In ST-SALVY (France), scheduling operations is not possible if not considering account resource allocation. In any stope within the vertical vein zinc deposit, the cut-and-fill method enables to mine each horizontal slice according to various strategies, de- pending how to use manpower and equipment, and selecting among predefined scenarios known as realistic. For KOFFIEFONTEIN (South Africa), the kimberlite pipe is mined by a sub-level-stoping method. To achieve the production target, precise organization over one month is obtained, using on& resources when available and respecting all mining rules. This combined operation scheduling and resource allocation is called sequencing. While following the BONANZA concept, providing a planning- retrieval process, sequencing offers more. Very detailed, it is possible to check the impact of resource parameters and mining rules. The sequencer, like a simulation platform, enables expertise. Each sequencer must be tailor-made to fit to each specific mine. The next challenge is to produce a generic environment.

Jan 1, 1996

By H. R. Stahi

THE ore of the Southeast Missouri lead district consists essentially of galena in dolomitic limestone. The galena usually is in a very finely disseminated condition. The experience of recent years in the concentrating plants of the St. Joseph Lead Co. has shown that dry crushing carried to a point where about 90 per cent of the ore passes a 14-mesh screen liberates the larger portion of the galena, and minimizes further necessary reduction in rod or ball mills. Concentration practice has attempted to carry size reduction to a point where economic unlocking of the galena is obtained, without causing undue sliming of the very friable galena. While 60 per cent of the tonnage of the district is treated by the flotation process, only 40 per cent of the total concentrates is produced by that means, as efforts have always been made to keep the grade and tonnage of flotation feed as low as possible. The milling practice of the district for some years has recognized the generally accepted idea of better selective grinding in rod mills as compared with ball mills, with the attendant decrease in production of fines. The function of rod and ball mills in the various concentrating plants is the grinding of table middlings and coarse tailings that carry lead values too high to be discarded. The simplified flowsheet in Fig. I illustrates the place of grinding mills in the circuit. The arrangement of classifiers, tables and mills constitutes a closed circuit within somewhat flexible limits. In 1937 experiments were conducted in replacing the ball charge in a 6 by 4-ft. ball mill with rods 2 in. in diameter and 51 in. long. This step was taken with some hesitancy, as it was easy to picture a mass of tangled and crossed rods. However, no difficulties developed, and after a short trial period, six more ball mills were converted to rod mills. These mills are of the spur gear and pinion, belt-driven type, using in most cases a 75-hp. motor and having a 9 1/2 -in. open trunnion discharge. As ball mills, they carried a charge of 16,000 to 20,000 lb. of balls, 2 in. in original size. The feed to the mills was dewatered by dewatering wheels and introduced at 70 to 75 per cent solids, with a single scoop feeder. One change in mill design was found advisable when rods were introduced. The existing end liners had an outward flare of 3 ½ in. in 12 in. These were replaced by linings having vertical interior faces, in order to prevent undue end travel of the rods. This change gave an effective working length of 5 2 ¾ in. inside the mill. No alterations were made in the shell liners, which are of the smooth type, made of manganese steel 2 in. in original thickness. The rods at present in use are 51 in. long and 1 3/4in. in diameter. The composition has been varied at times; at present they contain 0.70 per cent carbon and 0.70 per cent manganese. Some breakage and etching occurs as the rods become small, but this is considered preferable to using softer rods, which may kink and cause tangling of the charge. The mill charges are renovated occasionally, broken pieces being removed and the charge brought up

Jan 1, 1945

By B.E. Hall

Maximizing shareholder value has become a common aim for mining companies. This paper discusses the results of a number of studies developing strategic mine plans, covering a wide range of commodities, styles of mineralization, mining methods, and processing facilities, for single and multiple deposits. It has become evident that traditional methods and conventional wisdom often do not in fact achieve these goals. Operating policies at many mines ensure that shareholder value is not maximized. Changing the overall strategy can provide significant value gains. Typically, the new optimal plan involves a significant increase in the cutoff grade, at least in the earlier years. An increase in the underground development rate or open cut stripping rate is often associated with this, at least in the short term, to establish the new strategy. Cost minimization is found to be counter-productive. Counter-intuitive plans are often found to be optimal. For example, optimal cutoffs for different parts of an underground mine may be significantly different, even if mineralisation and cost structures are similar. Sub-optimal strategies are also frequently found to have a significantly greater financial risk than optimal plans, which have been found in many cases to be relatively insensitive to changes in major value drivers, such as metal prices. This paper shows how identifying and then operating within the framework of an optimal strategic plan can have substantial benefits over being continually driven by short-term tactical issues.

Jan 1, 2009

To pinpoint dust sources and to improve dust control on longwalls. Approach Use short-term gravimetric sampling to determine the severity of various dust sources, and to evaluate dust control techniques used in longwall mining. Short-term gravimetric sampling can be used to isolate dust levels produced by various dust sources. How It Works Traditionally, gravimetric samples have been collected over an 8-hour shift, yielding time-weighted, average dust concentrations. This method gives a good indication of the full-shift respirable dust exposure of underground workers, but is less than satisfactory for identifying dust sources, determining their severity, or for evaluating the effectiveness of dust control techniques. Short-term gravimetric sampling uses equipment available to all mine operators. Two individuals composing the survey team each collect multiple (three to four) gravimetric samples during selected segments of the mining cycle. Multiple samples are necessary to insure accuracy, and to obtain a valid average measurement of the respirable dust concentration when sampling for short periods of time (typically 20 to 30 minutes). The gravimetric instruments may be carried in a sampling package or in a "sampling vest." A fishing vest with four large pockets can be used for this purpose. The sampling pumps are carried in pockets and the sampling head assemblies arc hung across the front of the vest.

Jan 1, 1982

By M. Kumral

The in-situ mineral characteristics of a deposit are simulated by sequential co-simulation and averaging the simulated characteristics within specified block volumes creates a three-dimensional block model. This model is then submitted to optimal open pit and production scheduling algorithms. As the market values of industrial minerals depend on the satisfaction of predetermined blending criteria rather than metal content, a Linear Programming (LP) scheme has been used to identify all blocks that can be included in the blend without violating the grade requirements. The Lerchs-Grosmann algorithm using the blocks identified by the LP program determines optimal pit limits. All blocks that lie outside the optimal pit are removed from the system and the blocks within the optimal pit are submitted to the production-scheduling algorithm. Production scheduling optimisation is done in two stages: Lagrangean parameterisation, resulting in an initial sub-optimal solution, and multi-objective simulated annealing (MOSA) improving the sub-optimal schedule further.

Jan 1, 2002

By Fernando Muge

A complex pyrite orebody located in the South of Portugal (MO INHO) was exploited in the past by cut and fill methods until a certain level. It was decided to design a new plant for non ferrous metal extraction and the rate of production and exploitation method was modified accordingly. So, a sub level stoping (SLS) method was en visaged for the exploitation of the deepest part of the orebody (under 265 m level). For the planning of this SLS method, it was decided to perform a geostatistical study of the orebody, on the basis of the available information, which consists mainly of channel samples assayed for Cu, S, Zn and Pb.

Jan 1, 1979

By E. Ben-Awuah, H. Askari-Nasab, N. Al Habib

Open pit mines are getting deeper with time and transportation expenses are increasing because of the increasing haulage distance. In-pit crushing and conveying (IPCC) is getting popular in deeper open pit mines as a suitable alternative to truck haulage because it offers a lower operating cost due to shorter haulage distance and less truck requirement. Semi-mobile in-pit crusher, currently the most popular IPCC system, is relocated every two to five years and the short-term plan needs to be updated accordingly. Short-term planning with IPCC is an area of research that has not been explored extensively yet and hardly any model can generate short-term extraction sequence considering an IPCC in place. This research work proposes a mixed integer programming model to generate short-term production plan within a time horizon of 12 months. The objective of the model is to optimally allocate shovels to minimize cost of material handling and maximize revenue subject to meeting plant requirement, maximum allowable tonnage variation and IPCC location constraints to achieve production and NPV targets set by strategic plan. The proposed model has been implemented in a hypothetical case study for verification. The comparison of results between scenarios with and without IPCC is expected to justify the use of IPCC in large open pit mines from a short to medium term perspective. A semi-mobile IPCC system with one relocation is considered in the case study.

Feb 1, 2023