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By M. E. Rossi

This paper discusses the use of Conditional Simulation (CS) models to provide mill feed grade profiles for different time periods. The conventional approach of classifying block estimates as ore or waste generally does not adequately represent dilution, lost ore and the anticipated grade control data, including variability of mill feed from the pit and possible stockpiles. The detailed simulation of grade control practices can be done, but at the Pre- or Feasibility stage of the project may be impractical, since drawing dig limits on multiple benches is tedious and time consuming. Using the Feasibility Grade Control (FGC) method as developed by the Centre for Computational Geostatistics (CCG, University of Alberta-Edmonton), the CS models can be processed quickly to establish dilution and lost ore, and predict daily or short-term feed to the mill. The simulated nodes can be aggregated into selective mining units with adequate representation of likely geometries to be recovered from the pit, to mimic anticipated selectivity. An example from a large copper deposit is shown. The study provides an estimated stream of tonnages and grades fed to the plant by mining periods of interest and based on a specific mine design and schedule. The resulting cash flows support the economic and financial analyses of the Feasibility Study; also leads to improving mine schedules; and aids in developing blending schemes if necessary. INTRODUCTION The conventional approach of separating mineralized material into ore or waste categories does not always include a realistic amount of dilution and ore loss. Also, often it does not provide a good estimate of the grade that will be fed to the mill. If the grade control estimates are unbiased, they will over the long run represent the long-term average of grades fed to the mill; but the anticipated variability of mill feed from the pit and stockpile sources may be misrepresented. Some references on traditional grade control implementations can be found in Chunnett (1982); Davis et al. (1989); Srivastava et al. (1992); and Nowak (1992). Alternative methods based on economic variables improved significantly on the purely grade-based control methods, see Douglas et al. (1994). Further developments involved the use of geostatistical conditional simulations (CS) and profit models, which in several cases have been successfully implemented (Aguilar and Rossi, 1996; Rossi, 1997; Deutsch et al., 2000; Norrena and Deutsch, 2002; Neufeld, 2005; Jewbali and Dimitrakopoulos, 2009). But they can be impractical, mostly due to the lack of understanding of the methodology involved; even if semi-automatic dig limit drawing is implemented, there is always a need for is tedious and time consuming checking and corrections, even if using a single profit model derived from the simulated grades.

Jan 1, 2019

By S. K. Ash

In arriving at economic losses in coal mining due to accidents, a statistician is confronted with many difficulties on account of the lack of information relative to nonfatal accidents. For comparative purposes the ex¬ perience of those countries, States, or companies that keep complete records can be drawn upon and an extimate can be arrived at whereby one State can be compared with another, or one mine compared with another in the same district. Such a comparison for the United States has been compiled by the United States Bureau of Mines. It will be observed in Table 1 that the cost per ton for accidents in the State of Washington for the year 1927 is higher than for any other State, with the exception of Georgia and North Carolina, with a small combined tonnage of 130,089 tons. (The figures for coal production in Table 1 are taken from Bulletin 319, 1930, of the United States Bureau of Mines.) The reasons why the cost of accidents in Washington might be higher than the average are on account of physical conditions such as steep pitches, faults, igneous intrusions, highly explosive coal-dust, extremely friable coals, presence of gravel and water, very gassy coal beds, rugged topographic conditions, inherently bad roof and floor, thick beds, and heavy cover. The nature of the coal beds requires the use of preparation machinery. The mines are often deep, and topographic conditions are such that long and fast haul¬ age becomes necessary. All of these factors not only tend to cause high cost of production, which is manifested largely in a. lower than average daily pro¬ duction, per man, but..they.also affect to some degree a tendency toward a higher than average cost for accidents.

Nov 1, 1931

By Clifford S. Gibson

A year ago a paper (1) was presented at the Annual Western Meeting of the Institute regarding silicosis in Ontario mines. It described the whole problem as we see it and discussed the means of prevention. The work and aims of the Technical Silicosis Research Committee of the Ontario Mining Association, and of the Committee's field engineer, were fully described also and it is suggested that reference be made to this paper in order to have a better understanding of the observations which are presented now. These observations enlarge upon parts of the dust control measures already discussed and tell of general progress in the past year. They concern fifty properties, the majority of the operating mines, which vary in size from the hopeful prospect to established producers yielding 11,000 tons of ore daily. Most of these are gold mines; a few copper-nickel. The ores range from heavy sulphides to siliceous materials and they are mined by many methods from varying types of deposits. The majority of the latter are steeply dipping and all are found in Precambrian host-rocks. Up to the present, die greatest depth to which mining has penetrated is 6,400 feet.

Jan 1, 1939

By Jeremy Spearman, Mark Lee, Jon Taylor, Neil Crossouard, Bramley Murton

"SUMMARYThis paper describes challenges faced when executing a programme of monitoring to measure the dynamics of currents and sediment plumes at a seamount and the solutions identified to deliver the measurements. The study site was the Tropic Seamount, which extends some 3300m above the surrounding seabed and is found at the southern limit of the Canary Island Seamount Province. The purpose of the study, which forms part of the Marine E-tech project, was to provide information on the interaction of flows with the seamount and to assess the behaviour of sediment plumes that could be generated from potential seabed mining operations targeting the recovery of ferromanganese crusts. Since the crest of the seamount is submerged to a depth of 1000m, much of the work was undertaken using remotely operated and autonomous vehicles supported by measurements from the surface vessel. Despite only limited information on currents being available for planning purposes, the combination of short term forecasting using a 3-dimesional hydrodynamic model of the study area coupled with the collection and analysis of reconnaissance data collected during the first phase of measurement activities made it possible to plan and execute a number of detailed hydrodynamic experiments on the seamount crest. The results of these experiments have advanced the understanding of the behaviour of sediment plumes in the deep ocean and will ultimately improve our ability to manage the impacts which may arise from deep sea mining operations."

Jan 1, 2017

By Charles L. Harness

Magnesia (MgO) has a variety of uses, and it has become increasingly important as a war material because of the imperative demand for refractories to line metallurgical furnaces, and because magnesia is used to make the in aircraft and other implements of warfare. Magnesia occurs as an integral part of nearly 60 minerals, but it is extracted commercially from only a .smaller number, of them. The present commercial sources are magnesite, brucite, dolomite, raw sea water, sea water bitterns, and well brines. Magnesia Raw Materials Magnesite magnesium, carbonate MgCO3, theoretically contains 47.8 percent MgO and 52.2 percent CO2. There are two varieties of magnesite, crystalline and cryptocrystalline (dense or amorphous). The latter type, though, not so plentiful as the former, is generally purer. It resembles unglazed write pottery in texture, whereas the crystalline variety is generally dark and granular, though the color may vary. The principal domestic deposits, of crystalline magnesite are near Chewelah, Stevens County, Wash. (which has supplied most of the magnesite mined in the United States), in the Gabbs Valley area of Nevada (near Luning); and in Llano County, Tex. Crypto-crystalline magnesite occurs principally in California. Magnesite occurrences have also been reported in several other States, including New Mexico, New York, New Jersey, Pennsylvania, Massachusetts, Vermont, and Maryland, but these deposits have not been developed commercially.

Jan 1, 1943

By Vijayakumar Viramuthu, Martin Heinrich

Tower of Lot L, L1 & M, Kuala Lumpur City Centre when completed would stand 700 m tall. This Mega tall Skyscraper would merely be less than 500 m away from the world tallest Twin Tower, the Petronas Twin Tower. From June 2018 to February 2020 BAUER (MALAYSIA) SDN. BHD. constructed 225 nos bored piles with diameters of 2.0 m and 2.5 m for this tower. To comply with the depth requirement of the initial design and the need to have the pile toe 2.0 m above competent bedrock, the drilling equipment was required to be able to achieve a maximum drilling depth of 150 m. Actual piles constructed on site were deeper than 120 m. These dimensions caused superlative challenges which included but were not limited to controlling the open borehole stability over time with polymer, installing 70 t heavy steel cages and pouring up to 550 m³ concrete continuously in conjunction with installation of 88 t heavy kingposts into workable fresh concrete. The piling works were executed with one BAUER BG 48 and one BG 72, the biggest drilling rig globally available.

May 1, 2022

By E. Kuipa, J. N. Lekunze

The selection of an underground mining method stems from a multivariate analysis that considers geomechanical, geological, economic, and operational parameters. Even after identifying the most compatible method, there is no assurance that the mining company will achieve the best performance. The geological complexity of some deposits requires adaptations of methods described in the literature to obtain more selectivity and reduce mining waste. There are some studies on geometry of underground structures, but a methodology that describes an adaptation of a room-and-pillar mining method for ore bodies with down-dip varying from 20° to 25° is novel. The present work aimed to reduce dilution by adapting the traditional room-and-pillar mining method (TRP) to inclined ore boLittle attention has been paid to the rehabilitation of derelict and ownerless mines in South Africa after their lifespan. This paper aims to explore management gaps in legislation that have resulted in the non-rehabilitation of derelict and ownerless mines in South Africa. There is growing evidence that supports the distressing effects of mining on people living around these mines in the North West Province. This paper was motivated by the current socio-economic status quo of old mining towns, the influx of illegal miners (Zama Zamas), severe environmental damages, and the violence associated with derelict mines. Underpinning this research was an ecosystem approach and integrated resources management principles, which formed the foundation for the decision-making process.The researcher used a mixed-method approach and employed convergent techniques. A semi-structured instrument was used to collect data from 200 respondents. The results indicated that there is a dire need for community-based consultative processes, and an absence of clear guidelines for derelict and ownerless mines to pressure mine management to adhere to rehabilitation standards. Moreover, the mining charter is ambiguous regarding policy implementation, budgetary allocation, and duration of the rehabilitation of these mines. The paper concluded that management challenges associated with derelict mines can be reduced if all stakeholders follow the guidelines as outlined in the environmental legislative framework (NEMA) of South Africa while being open to innovations in line with international best practices. It also contributes towards the development of guidelines for the management and implementation of legislation related to derelict and ownerless mines in South Africa from a philosophical, theoretical, and policy perspectivedies. This new method is entitled short-hole room-and-pillar (SHRP). The equations that measure the dilution are defined according to the geometry of stopes and openings. The results comprise comparative analyses of the operational and planned dilutions to measure the performance of the SHRP method. The average operating dilution of the SHRP method was more than five times lower than the planned dilution according to the TRP method. Low operational dilution indicates high selectivity of the method and its potential to reduce underground mining tailings.

Oct 9, 2024

By Fabiano Soares

Strand guide rolls in continuous casters are crucial components for guaranteeing an optimum process for the production of high-quality steel grades. The properties of these rolls greatly influence the quality of the slab produced. The most commonly used designs so far have been the axle roll and the solid roll. A quite new roll concept is the STEC-Roll®. It combines the advantages of the axle roll with those of the solid roll. This paper explains the development of this roll type and shows the current design. The characteristics of the STEC-Roll® are presented in greater detail and are underlined by a number of simulation results. Beside the design itself, the benefits for casting and maintenance are explained, including for example the easy assembly and dismantling or the use of the roll for dry casting. A brief examination is made of the TCO for the STEC-Roll® and an estimation is provided of the exchangeability of this roll. To conclude, an overview on the current applications is presented.

Aug 17, 2017

By I M. Platten, C J. S Sangster, Y Xie, S C. Dominy

Cononish is a steep, narrow NE-SW trending vein system that was emplaced into late Proterozoic metasediments. It shows brittle style deformation and postdates metamorphism and associated Caledonian foliations. The ore shoots plunge 45¦SW, have a 40 to 80?m intersection with the existing underground development and extend between 40 and 260?m down plunge. Small-scale sulfide-bearing domains within the vein carry the highest gold grades. They collectively define the ore shoots, where one or two and rarely three of the domains are present at an individual site in the vein. Gold occurs as electrum, with minor native gold. Silver occurs additionally as tellurides and native metal. The gold/electrum is fine-grained, generally <100?¦m in size and locally clusters. Visible gold up to 2000?¦m in size is rare. Gold and silver are generally spatially associated with sulfides in quartz. The main sulfide is pyrite, but galena, chalcopyrite and sphalerite occur also. Electrum and gold occur with galena in pyrite-hosted fractures. Gold is also associated with the contacts between galena and pyrite grains. Discontinuity of individual domains, variation in domain thickness and internal heterogeneity results in short scale variation in grade across the structure. Over 16?km of diamond drilling and a 1.2?km exploration adit has provided data to support a Mineral Resource estimate of 169?000?oz Au and 631?000?oz Ag reported in accordance with the 2004 JORC Code.CITATION:Dominy, S C, Platten, I M, Xie, Y and Sangster, C J S, 2013. Gold-silver vein mineralisation at Cononish, Scotland, in Proceedings World Gold 2013 , pp 445-454 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Marvin S. Seppanen

Computer programers are often required to make modifications to unfamiliar Fortran routines. This Bureau of Mines report describes a computer program designed to aid the programer in such a situation by reorganizing: Fortran routines. This reorganization includes a sequential renumbering of the routine's statement numbers, a sequential renumbering, and relocation of format statements, an alphanumeric reordering of dimensioned and typed variables, a uniform pattern of text spacing, and a sequential numbering of the records in the final Fortran routine. The computer program has been extensively tested by the author and has proved to be a valuable tool for reorganizing Fortran routines developed under contract and later utilized by the Bureau, and for preparing routines for publication.

Jan 1, 1975

By K Peters, C McKenzie

New Zealand has an established history of gold production beginning with the gold rushes of the 19th century in the Coromandel, Nelson/Marlborough, West Coast and Otago regions. Despite this, the number of significant modern hard rock gold operations has been limited in recent years due to a lack of sustained exploration capital and not limited geological prospectivity.The New Zealand Government is actively encouraging explorers to invest in New Zealand through a series of targeted promotional visits, more importantly through the acquisition of precompetitive regional geophysical data. Data collection has been completed over the prospective Northland epithermal district and a large portion of the South IslandÆs west coast that is prospective for both orogenic gold and intrusive related gold.Analysis of new data has been an important component in aiding the generation of exploration targets from prospectivity modelling. Determining the prospectivity of an area involves reviewing all the available data and analysing it with respect to the most up-to-date mineral system model for the mineralisation style of interest. Using the weights of evidence modelling approach, the most prospective areas for epithermal gold-silver, orogenic gold and intrusion-related gold have been identified. The key exploration parameters relevant to each mineral system are first represented spatially and then statistically combined into a single prospectivity map. New potentially economic deposits could be found by focusing exploration on targets identified from these models. The prospectivity modelling approach can greatly reduce the risk involved in mineral exploration.CITATION:Peters, K and McKenzie, C, 2013. New Zealand gold potential - using mineral prospectivity modelling to evaluate gold-bearing mineral systems in an underexplored country, in Proceedings World Gold 2013 , pp 479-486 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By M Watson, A V. Engelbrecht, E Murray-Hayden

Whereas mine reconciliation is a well-established month-end process for most modern mining operations, the resource sector has yet to endorse uniform reporting factors against which model accuracy and metal recovery can be formally assessed. Logically, any comprehensive reconciliation framework should facilitate comparison between period reserve, mine and mill and production figures. Historically, Parker’s F Series ratios (Parker, 2012) are often used in some form by mine operators, although they are rarely shared externally, as formal definitions have yet to be accepted. This paper presents a structural extension to the reconciliation process, wherein resource ratios (R Series factors) are used to quantify the long-term impact of the information effect, together with dilution and ore loss. A case study from the El Limón Guajes (ELG) Mine Complex in Mexico is used to demonstrate how an R Factor Series can be implemented to facilitate operation optimisation, over and above conventional F Series reconciliation treatments. This approach is applicable to any mining operation.

Mar 22, 2022

By Thomas C. Denton

ALL of the 45 political divisions of Africa were accessible to non-Communist world industry and commerce throughout 1964, although in some of them revolt and political attitudes presented problems. The position of the continent as a whole for mineral and mineral fuel resources, production, and oversea exports continued to improve. At yearend, significant quantities of a greater number of mineral commodities vital to industry and agriculture were being produced than in any other continent. This statement excludes Communist areas on other continents but might well hold true even if such areas were included. Deriving from its exceptionally diversified production, Africa furnished overseas industrialized countries as a w ole a greater variety of key mineral commodities than any other area. In addition, the value of mineral imports from Africa into the United Kingdom and continental non-Communist Europe probably exceeded the value of such imports from any other area if gold is included and mineral fuels excluded.

Jan 1, 1966

By Michael G. Zabetakis

Investigation of gas explosions usually reveals that the combustible gases have come from transmission and storage facilities or from natural gas or oil wells. However, combustible gases such as methane and hydrogen can derive from biological processes. Hazardous situations have been created in the past by the use of abandoned mines for the disposal of sewage and rainwater, by the interconnection of storm and sanitary sewers, by sealing the openings in manhole covers when repaving the roadway over a sanitary sewer, and by the construction of buildings over or near garbage fill areas without adequately providing for the release of combustible gases.

Jan 1, 1962

By A. G. Sharkey

THE PURPOSE of this investigation was to develop methods for analyzing coal derivatives and products from the Fischer-Tropsch synthesis. As part of this investigation it was necessary to study the mass spectral characteristics of many classes of compounds. The mass spectra of alcohols, the trimethylsilyl ether derivatives of alcohols, acetal-type compounds, ketones, esters, and naphthenes were correlated with structure, and analytical methods were formulated. A method was devised to determine the ratio of branched to normal hydrocarbons up to CIS in the Fischer-Tropsch product. Low-ionizing-voltage mass spectrometry was combined with type-analyses to analyze tar acids and neutral oils from coal. The necessary sensitivity correlations at low-ionizing voltage were developed, particularly for phenolic compounds. Special analytical techniques were developed for the mass spectral analyses of specific compounds and compound types including (1) oxides of nitrogen, (2) hydrogen sulfide, (3) isomers of butenes and pentenes, and (4) hydrogen deuteride. An investigation was made of the effects of various hydrocarbons and oxygenated compounds on tungsten filaments in the mass spectrometer. The operating characteristics of rhenium filaments under similar conditions were studied. Several improved sample handling techniques were developed, including an automatic manometer and a self-filling micropipet. Studies were made of anomalous and negative peaks in the mass spectra of certain gases.

Jan 1, 1967

By John J. Deutsch

"1T is a great pleasure for me to be present at the Annual Dinner of the C.I.M.; a pleasure which is combined with a mutual opportunity that I value highly. First of all, this occasion gives me a chance to meet again many Members of your Institute and to become more fully informed of the special problems of the mining industry. This alone is ample reason for me to welcome the invitation to join you tonight. In addition, this occasion provides me with an opportunity to tell you something about the work of the Economic Council which might be of particular interest to your industry.In the mining industry, keen competition and constant change are basic facts of life. The continuing prosperity of the Canadian mining industry depends fundamentally on how successfully it is able to adapt both to the changing conditions within the industry and to major trends which operate throughout the world.First of all, the scale and organization of the industry are evolving to new and different dimensions. As one authority has put it, ""The cream of the small high-grade, easy-to-mine ore deposits of this world have been consumed and mining is becoming more and more an industry of very large scale, complex operations. It has already become in most countries a capital intensive industry and its problems, scientific, technical and economic, are growing in difficulty."""

Jan 1, 1966

By I. Haskett

ABSTRACT The Redwater pool, in north-central Alberta, was discovered in October, 1948, and at the end of 1950 was about 85 per cent developed. Production is from a Devonian coral limestone reef and is found at an average depth of 3,150 feet. The pool has an estimated .productive area of 37,000 acres, and a maximum oil zone thickness of slightly over 200 feet. Wide variations exist in both type and values of porosity, with the average value determined for the reservoir being 6.16 per cent. The total stock tank oil in place is about 1.24 billion barrels. The crude has a saturation pressure of 485 psig, com-pared to the original value of 1,050 psig for the reservoir, and the principal recovery mechanism so far has been the natural water drive. Cumulative production to January 1st, 1951, has been about 15.5 million barrels. These withdrawals resulted in a reservoir pressure decline of slightly over 100 psi. Predictions of future behaviour indicate that the water drive will not be of sufficient magnitude to maintain the reservoir above saturation pressure past 1953, and that, with natural depletion, the pool will be produced largely by a solution gas drive. Pressure maintenance by water injection has been considered and the possibility of raising the pressure to the original value of 1,050 psig is also discussed. INTRODUCTION WITH the discovery of the Lewduc pool, early in 1947, the Devonian limestone became the major geological formation contributing to Western Canada's rapidly growing petroleum reserves. Redwater, discovered in October, 1948, is now the largest known Devonian pool in Canada, with a recoverable reserve estimated at approximately 500 million barrels. Until recent years, the knowledge of the nature and characteristics of this type of limestone reservoir has been comparatively limited.

Jan 1, 1951

By Alan Jessop

A small group has been set up at the Dominion Observatory, Ottawa, to make a survey of terrestrial heat flow throughout Canada. Terrestrial heat flow is the heat rising from the interior of the earth and escaping at the surface, and is calculated from a knowledge of under-ground temperature distribution and the thermal conductivity of rocks. A small number of diamond drill holes are being sunk for the purpose of measuring temperatures below the surface, but the program is inadequate for a thorough survey. Mines and holes drilled for other purposes are being sought by the Dominion Observatory group to supplement their own drilling program. F ROM January, 1.962, to December, 1964, geo-physicists of many nations will be cooperating in the "International Upper Mantle Project." Unlike tl1e International Geophysical Year, which was mainly concerned with the fluid layers surrounding the earth, the Upper Mantle Project is an intensive study of the solid earth. Canada, with its large land area and extensive Precambrian Shield, is an active participant in the project.

Jan 1, 1964

By Harold G. Moulton

IT is highly significant that engineers should seriously consider the interrelations of technology, economics, and government. It is indicative of the emergence of maladjustments and problems that perplex our thinking and frustrate our activities. Instead of a world in which scientific discoveries and their applications through engineering to the processes of wealth production are regarded as the royal road to progress, we now find science and engineering being made responsible, in no small degree, for our economic and social troubles; and the powers of government are even being invoked to stem the tidal wave of technology. Indeed, there is a deep-seated fear, manifested in the writings of some of our greatest scientists as well as in popular discussions, that science may destroy our civilization.

Jan 1, 1938

By Peter A. Hacquebard

"Two continuous coal zones occurring in a 2500f t (762 m) thick section of the Upper Carboniferous Pictou Group (Westphalian C and D) have been encountered in five offshore wells drilled f or oil and gas in the Gulf of St. Lawrence. They correlate, by means of fossil spores, with thick coals of the Mabou and Inverness coalfields situated at the eastern margin of the Basin. Therefore, the presence of a large submarine coalfield of at least 18000 sq mi. (46 620 km'] is indicated. This compares with an estimated size of 14 000 sq mi. (36260 km' ) for the Sydney Coal Basin.Accessibility is provided only by the small onshore parts of the Mabou and Inverness fields, because farther offshore the coals lie too deep to be mined (below 4 OOO f t ([ 219 m)).Two near-shore coal exploration wells indicate that at Mabou Mines the younger Inverness coals occur at a mineable depth to at least 5 km from land. A structure contour map of this area shows a reserve of 125 million tons in two Inverness equivalent seams that are 8.5 ft (2.6 m) and 4.5 ft (f.4 m) thick. The Mabou coals, however, reach too great a depth close to shore to possess mineable resources.A structure contour map of the Inverness submarine area, based on mine data and one off shore seismic profile, indicates inferred mineable resources of 160 million tons, in two seams that are 7ft (2.1 m) and 4.5 ft (f.4 m) thick . A detailed deep seismic survey will be necessary to substantiate the structure and resource estimates"",Maceral and coal quality percentage diagrams of five column samples of these seams (the 7 Foot and 13 Foot Seams of Inverness Equivalents) show a bright banded coal, high in reactive macerals, which will produce a weak coke unsuitable f or metallurgical purposes. A thermal coal with a rank of H. V. ""B"" Bituminous (0.64% Ro) is present, averaging 12000 btu llb (6 660 kcai/kg), 10% ash and 6% sulphur, of which 60 to 80% is derived from pyrite.Microlithotype profiles of the major Mabou and Inverness coals show characteristic successions that can be used f or seam identification and proved valuable f or structural interpretations.The time of faulting in the major fracture zone on the eastern margin of the Gulf of St. Lawrence Basin has been deduced from coal rank variations. It occurred in pos tPermian, probably Early Triassic time."

Jan 1, 1986