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By B Broad

"Establishing ventilation in the early stages of a new mine is an essential step to achieve scheduled outcomes that ultimately drive the financial success of an operation. If the primary ventilation is not in place in time to support a contractorÆs work output, then the ore delivery is likely to be severely impacted. Options to increase ventilation in order to address shortfalls are limited. This in turn can lead to reduced revenue generation at a time when a mine is at its highest capital outlay. This can have implications for any company, but even more for an explorer moving to producer. The ventilation put in place to cover the start-up period is also unlikely to cover any extended or increased load required to meet schedule delays.The following paper examines two issues in relation to ventilation with a focus on small to medium projects where the company is establishing a mine using a mining contractor. The issues being: potential impacts on the contract and tender process when using a mining contractor key mine design considerations, such as æcrunch timeÆ, as they interact with ventilation achieving a successful ramp up.A recommendation is made for higher levels of detail around secondary ventilation leading up to the primary fan installation. The information should be included as part of the tendering process and preliminary project execution planning. Understanding the æcrunch timeÆ concept can lead to strategies, as well as back up plans, to minimise any negative impact.By understanding key risks around primary ventilation establishment for a new mine, detailed design work can be completed where it is needed most. Value is added by reducing uncertainty and a payback with better contract terms and a more robust ramp up plan. This will improve the economic return for the company and reduce the risk.CITATION:Broad, B, 2013. Contract considerations and other critical ventilation aspects in achieving a new mine ramp up, in Proceedings The Australian Mine Ventilation Conference, pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 1, 2013

By Thomas T. Read

AT this time of the year, engineering schools are releasing a group of young men who probably are, on the average, in much the same attitude of mind as a person arriving at the terminal station of a railway journey; namely, of having a general idea of his objective, but having to make a decision as to just where he is going and how best to get there. The man leaving the train can at first follow the crowd, but it soon breaks up, as one goes one way and one another, until he has to choose his own course. The recent graduate may do the equivalent of following the crowd by accepting the first position offered, but this only postpones a decision as to where he is going and how best to get there. So many young engineers ask for advice as to what to do that the following statement has been prepared as an attempt to make a general answer to such queries. The engineer taking his first job should realize two fundamental relations. The first is that in electing to be an engineer he has elected to be a hired man. A consulting engineer has more freedom than a man on a regular pay roll, but he is also a hired man; hired for briefer periods at a relatively high rate, but under the necessity of simultaneously doing his consulting work and developing new retainers. There is nothing derogatory in being a hired man (all doctors, lawyers and clergymen are hired men), but the tardy realization that he is one seems to give many an engineer a mental jolt that can be avoided if he accepts it from the beginning.

Jan 1, 1926

By B. Meddings, O. J. I. Evans

"This paper is mainly concerned with the present and probable future role of hydrometallurgy in the production of base metals.The economic and technological bases of the hydro-metallurgical plants built and operative in the mid-fifties are compared to those in production in the mid-sixties. The trends observed are extrapolated and some estimates made concerning the probable size and type of hydrometallurgical plants which will be operative in the mid-seventies.The impact of emerging socio-economic factors such as pollution control and the market demand for specialized metal products which favour hydrometallurgical recovery processes are also discussed."

Jan 1, 1971

By MUSTAFA ERKAYAOGLU, ENVER YILMAZ

Coal is still a part of energy generation worldwide and has a significant role in the sustainable development of countries. The amount of shallow coal deposits is getting scarce, making efficient underground mining operations crucial for both local and global economies. In underground mining operations, longwall mining is a commonly utilized method to extract deep coal deposits. One of the leading engineering goals in longwall mining is increasing the efficiency of the system by investigating the effects of operational factors on equipment. This paper investigates the shearer performance for a longwall top coal caving operation by discrete event simulation that includes modeling the double-drum shearer, belt conveyors, stage loader, and armored face conveyors (AFC) to evaluate system performance by considering the amount of daily coal production of the shearer. As a result, the most influential factor on mine production is determined and a data-based framework is developed. This study suggests a framework for data collection, data analysis, and the interpretation of the operational data to evaluate the primary production unit’s performance. The models developed for the face coal extraction operations in a longwall top coal caving (LTCC) mine have a bi-directional cutting system and can be implemented in other operations readily.

Jul 2, 2021

Increasing depths and mechanization of underground mines have led to the production of large amounts of gaseous and particulate contaminants. Over 100 000 lives have been lost due to methane gas and dust explosions in coal mine workings in both the United States and Canada since 1900. There is, therefore, the need to constantly assess and evaluate the performance of existing mine ventilation systems to maintain safe and acceptable mine environmental conditions. This paper advances research initiatives in the control of methane gas in underground mine environments. It uses the results of continuous monitoring of methane gas concentrations conducted in selected coal mines in North America to assess the effectiveness of existing auxiliary ventilation systems to control methane gas concentrations. The results show that the average quantities of fresh air required to dilute, disperse and remove methane gas concentrations within set levels of one minute varied from 5.43 m3/sec. to 27.97 m3/sec. in the development headings. The average dilution times in the headings studied were less than eight minutes. The calculated dilution efficiencies of the auxiliary ventilation systems in the headings varied from 12% to 139%. These efficiencies ranged from poor to excellent. This implies that the auxiliary ventilation systems were capable of controlling the methane gas concentrations below statutory levels but may not be able to cope with large and unusual methane gas concentrations in the headings. This study is significant in the control of methane gas and coal dust explosions in coal mines.

Sep 1, 2001

By S K. Das

An intensive investigation into modern roof support technology, including hy draulic and control systems, has been carried out against the perspective of global development and support behaviour on longwall faces across the Indian sub-continent. The wide ranging study examined various types and designs of modern supports used in seams of varying thickness and inclination where caving and stowing were practised. Consideration has been given to structural analysis, support resistance, the various forces acting over and on the powered supports and to support compatibility. The examination of the phy sical parameters has been allied to field experience and, together, have led to the formulation of standard designs for both the powered support structure and structural systems. A realistic mathematical model has been formulated for calculating the capacity of roof support requirements resulting from the actual behaviour of the immediate roof stratum. As a result of the work, it should be possible to readily select the most appropriate type of support sy stem for the conditions and longwall mining method that is to be employed.

Jan 4, 1997

By D Frantzos, J J. Cotter, H Tammemagi, J B. Codrington, J Kaasalainen, A C. Webster

"Exploshres Technologies International (ED) is developing an instrument called ROCSCAN which isplanned to have broad application in both blasting and rock mechanics. The purpose of this paper is to outllne the background that has led to the development of ROCSCAN, describe its objectives and to present a progress report on the work to date. Some of the potential applications of ROCSCAN will also be reviewed."

Jan 1, 1989

By William O. Vanderburg

This paper describing the mining practices at the Argonaut mine, Amador County, California, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The mining practices described are those used in exploiting the low-grade gold ores in the heavy and swelling ground that occurs on the Mother Lode belt. The author acknowledges the assistance of E. A. Stent, vice-president, James L. Fontenrose, cost clerk, Joseph Mohorovich, mine foreman, of the Argonaut mine, and of E. D. Gardner, supervising engineer, United States Bureau of Mines, Southwest Experiment Station, Tucson, Ariz.

Jan 1, 1930

By C E. Vidal

Geological exploration and mining development increased their intensity and rate of success during the last five years in Peru. Particularly relevant are the mining projects of Yanacocha and Pierina for epithermal Au and Ag. Also relevant are the new mining operations at Iscaycruz and Uchucchacua for limestone replacement Zn- or Ag-rich base metal skarn deposits. Miocene continental volcanics host the low-grade but near-surface orebodies of the Yanacocha mining district in Cajamarca. Several deposits have been mined since 1994 with open-pit and heap-leach gold production increasing from 300 000 ounces to 1 300 000 ounces in 1998. In a similar geological setting, but with three times the grade of Yanacocha, the Pierina valley-leach operation in Ancash is set to produce 800 000 ounces Au during 1999. At Iscaycruz in Lima, Cretaceous limestones host massive pyrite and sphalerite skarn deposits with 10 to 20 per cent Zn. Mining and milling were started in 1996 with last yearÆs production rising to 180 000 tonnes of Zn concentrates. At Uchucchacua, selective underground mining of fracture-controlled Ag skarns, with 400 to 420 g/t, has been recently increased from 1200 to 2000 tonnes per day to produce 5.5 million ounces Ag during 1998. Advanced exploration projects are located in the framework of nine Phanerozoic metallogenic provinces. Mineral deposits of preferred attention are precious metal disseminations and veins, base metal replacements and skarns, porphyry Cu (Mo-Au), Mississippi-Valley-type Zn and base metal volcanogenic massive sulphide deposits. Geological discovery of new orebodies enables a sustainable development of the mining industry in the country.

Jan 1, 1999

By Richard I. Grass

The White Pine Mine is located 4- 1 /2 miles south of Lake Superior in the western part of Michigan's Upper Peninsula. The orebody occurs in tabular, gently dipping Keweenawan sediments. GEOLOGY The orebody outcrops beneath 30-50 feet of Pleistocene clays and dips to the east and northeast to a depth of 3, 000 feet in five miles. It lies midway between the Porcupine Mountains and the Bergland Hills, both of which are steeply dipping felsite and coarse porphyry intrusives, extrusives and sediments (Figures 1 and 2). The orebody sediments were deposited in the Keweenawan basin during mid- and upper Keweenawan times. Mineralization occurs in the basal 20 to 25 feet of the Nonesuch formation, which is made up primarily of laminated siltstone s. Native copper, chalcocite, and silver are the ore minerals. The ore is mined by trackless room-and-pillar methods.

Jan 1, 1967

By Oliver M. W. Sprague

THIS gold problem is full of complications and can hardly be handled adequately or comprehensively in any short period of time. Perhaps I might begin by mentioning a few aspects of the subject about which I suppose there will be no disagreement. The first of these is that we already have a stock of monetary gold in the United States far in excess of what is needed to support any desirable increase in the present volume of currency and credit. The second is that this already superabundant gold stock is certain to be considerably enlarged during the course of the war, and presumably during the months of readjustment following its conclusion. Some billions of additional gold, we may reasonably presume, will come into the country during these next few years, thus increasing the aggregate monetary gold stock from the present eighteen billions to perhaps twenty- two or even twenty-five billion dollars.

Jan 1, 1940

By A. D. Hammond

Vanadium is a transition metal, ductile and silver-gray. It is harder than most metals and steels and it has a good resistance to corrosion. It is stable against alkalis and sulfuric and hydrochloric acids. Vanadium is oxidized in air at about 660° C (1,220° F), although an oxide layer forms even at room temperature. The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states, 2-5. In aqueous solution, the colors are lilac V2+, green V3+, blue VO2+ and, at high pH, yellow VO42-. Considered to be as abundant as zinc, metallic vanadium is not found in nature, but it is known to exist in about 65 different minerals. Economically significant examples include patronite (VS4), vanadinite (Pb5(VO4)3Cl), associated to the uranium mineral carnotite (K2(UO2)2(VO4)2?3H2O) and in a vanadium mica called roscoelite K(V3+,Al,Mg)[(Si,Al)4O10] (OH)2. Other important vanadium ore oxides are montroseite (V,Fe)O(OH) and corvusite (Na,Ca,K)V8O2.4H2O. Much of the world?s vanadium mine production comes from magnetite-hosted deposits and, to a lesser extent, sedimentary-hosted sandstone.

Dec 1, 2013

By T. L. CONDRON

DURING the past fourteen months, this committee has had under consideration and study the subject of the licensing or registration of engineers. The fifteen members of the committee as appointed by Council, were selected from thirteen states, viz., Connecticut, New York, Pennsylvania, Ohio, Georgia, Louisiana, Illinois, Missouri, Iowa, Minnesota, Colorado, California and Washington, and therefore represent practically all sections* of the United States, as well as mechanical, electrical, mining, hydraulic, municipal, sanitary, railway and' structural engineering, and also colleges of engineering. The first work of the committee was to investigate the general subject and to collect, so far as possible, avail¬able material bearing upon the subject in hand,. in-' eluding opinions from many engineers as to the need or desirability of legislation, as well as copies of all state laws passed and proposed, having to do with licensing or registration of engineers, architects and surveyor, This preliminary investigation disclosed that very pronounced views were held by engineers throughout the country, both for and against state licensing or registration. The general sentiment one year ago was more opposed to such measures than it is today. The older members of the profession did not as a rule favor licensing nor did they feel there was need for state regulation of engineering practice, while among the younger men there was a feeling that licensing or registration by the states would add prestige to professional engineers and in many ways benefit -the profession, as well as individual engineers.

Jan 1, 1920

By T. Veneroso

Comminution is the process by which rock or ore is reduced to a size where the liberation of the minerals is maximized without changing the chemical or physical properties of the rock. Comminution accounts for about 50% of all energy that mines use (Klein et al., 2018). Growing demands from stakeholders and shareholders for sustainable development and CO2 reduction will increase the need for energy-efficient comminution. Ores with different mineralogical characteristics, textures, strengths, apparent stiffness, and mass-specific fracture energies need to be processed with a specific, new, and efficient comminution technology to increase the production and profitability of mining companies. The adoption of crusher wear parts built with new materials, such as non-Hadfield manganese steel or synthetic materials or traditional manganese with wear-resistant components, could improve the efficiency of the crushers, reduce downtime, increase production, improve the desired P80 (the aperture through which 80% of the product will pass) product size distribution, and enhance mine safety.

Feb 1, 2023

By Joseph D. Davis

The term "fusain" was first adopted from the French by the American geologist J. J. Stevenson in 1911, according to Wheeler, (1),3 who applies it to that portion of coal resembling charcoal, which he treats as one of the four ingredients of banded bituminous coal. The term has since been adopted by American writers. The Germans use it with slightly different spelling - namely, fusit. It is the equivalent of "mother-of-coal" and "mineral charcoal" of the earlier British writers. The English word fusain is also applied to "a crayon of fine charcoal" and is derived from the Latin root fusus. OCCURRENCE OF FUSAIN IN COAL AND ITS RECOGNITION Fusain is fairly widely distributed in coals of all ranks in varying amounts. It is almost always present in very thin sheets between the bedding planes of the banded coal constituents and presents a jet-black silky appearance who n the coal is split away. As fusain has little cohesive power the coal splits readily along the planes where it occurs. Such fusain bands often attain appreciable thickness -- frequently 1/4 to 3/4 inch. -Beet (2) has reported a maximum thickness of 2 inches for fusain partings, and Sinnatt (3) has found it in the form of plates and lumps; one lump taken by him from the Peacock mine weighed 3-3/4 pounds. Bore (4) has found it in coal balls. Sinnatt (3) states that fusain occurs in two forms, "the first a hard compact variety occurring rather rarely, which can not be pulverized by pressure of the fingers the second type is the common substance" -- that is, a very friable, easily pulverized material. The writer has also found the two types of fusain in the same coal bed and has observed that the hard variety contained considerable calcium carbonate, which probably entered the material in situ by infiltration. Sinnatt further remarks that the layers of fusain (soft type) usually contain less moisture than the coal (or lose it more readily on exposure), and when exposed they quickly change to flocculent powder so that the fines of the coal as mined are likely to contain a major proportion of this substance.

Jan 1, 1929

Project-finance risk assessment is mature and approached systematically. Mining industry due diligence remains fragmented with specialists addressing different aspects of the project such as reserves/JORC, environmental impact, commodity market, even financial analysis/ modelling. Each professional has a natural tendency to believe that the risk factors they have examined are the key ones necessary to be reviewed, as if their review will stand in isolation from others in the way a project materialises. By first laying out the project risk categories and risk matrices, this paper examines the due diligence process with a keen eye to the risk assessment and overlap/interaction. Some cross fertilisation of due diligence techniques from other industry sectors is placed into the mining context. Six case studies are then presented with regards to due diligence features in each projectÆs feasibility review or financial information/ offering memorandum. A power case first shows the differences between the due diligence expectations of banks versus bond financings. Then some Australian and Indonesian mining development cases are analysed to see the due diligence learning points. Some of these were project/due diligence failures. The conclusion focuses on the value of a systematic risk assessment for project evaluation, all from the project-finance perspective.

Jan 1, 2007

By T. F. Witherbee

THE following calculation of heat requirement covers the working of the furnace from January 25th to February 14th, inclusive. A short time previous to the first date the furnace had been working rather badly, so that 300 lbs. of ore and 500 lbs. of limestone were taken off. Within the time mentioned the quality of the iron passed

Jan 1, 1877

By T. F. Witherbee

The following calculation of heat requirement covers the working of the furnace from January 25th to February 14th, inclusive. A short time previous to the first date the furnace had been working rather badly, so that 300 lbs. of ore and 500 lbs. of limestone were taken off. Within the time mentioned the quality of the iron passed

By Huleatt M, Perkin D, McLeod I, Mock C, Pratt R, Gourlay A, Timoney E, Knight N, Ward J

Generally speaking, Australia's reserves of its more important minerals (in terms of export earnings) are adequate to sustain forecast rates of production to the year 2000. The rate of forecast production increases of these commodities (aluminium - whether as bauxite, alumina or metal, black coal, iron ore and ferro-alloy minerals, base metals, tin, uranium, and mineral sands) reflects a well- ordered and sustained growth phase of Australia's mineral industry.

Jan 1, 1981

By Jacques B. Wertz

Detailed structural studies in southeast Arizona have successively revealed (1) the local attitudes of individual fractures (with lateral and/or vertical displacements), (2) the patterns exhibited by groups of fractures, and (3) the trends and directions shown by fracture groups or zones on a regional scale. The results of the studies have been twofold: First, domes were locally determined from these fracture arrangements, even where other criteria failed; and, second, fundamental breaks brought out the breadth of the Texas lineament in southeast Arizona as well as major northwest- and northeast-trending fracture zones. Coincidence of one or several domes with the major intersections of fundamental breaks can be centers of important mineralization, as in the instances of Bisbee, Ajo and Morenci. THE OVER-ALL STRUCTURE OF ARIZONA A northwest-southeast trending anticlinorium has been suggested as the structural setting of Arizona. Starting in Triassic and culminating in late Cretaceous times, this deformation resulted from stresses of considerable magnitude with varying ratios of com pres sional and uplifting forces. However, the series of parallel flexures could just as well have been caused by isostatic movements involving dilation under tension with only incidental compression, as later emphasized by dike filling and block faulting (Fig. 1). The anticlinorial deformation, which is also suggested by the fact that the Pre-cambrian rocks to the southwest are all concealed by sediments, could be somewhat reminiscent of the conditions that affected the classical swarm of parallel dikes of wager.' ANALYSlS OF DATA As a first step in this analysis, all structural information obtained on such features as fractures and their relative displacements, faults, dikes, anticlines, synclines, and Precambrian and Laramide-Tertiary intrusives were plotted on maps along with structural trends inferred from aerial photographic mosaics. Next, the faults in southwest Arizona were classified according to time of occurrence and relative importance. The fault assemblages were then examined as to geometric or spatial arrangement and correlated with the occurrences of domes and existing Finally, the conjunction of fracture intersections and domes was analyzed and compared with locations of known ore deposits. Differentiation of Faults According to Time and Relative Importance: The faults encountered were grouped as follows: (1) Basin and Range faults, latest in time; (2) secondary faults; (3) primary faults; and (4) lineaments, earliest in time by inference. BASIN AND RANGE FAULTS- Generally concealed by alluvium, the Basin and Range faults are normal

Jan 1, 1969