Search Documents

By R Fletcher

Pacific Hydro, a leading renewable energy company from Australia, is developing a series of cascading run-of-river hydro electricity projects in the Cachapoal Valley at the base of the Andes Mountains some 100 km south of Santiago in Chile.These projects involve extensive tunnelling and underground works. The first of these projects is called Chacayes (110 MW installed capacity) and is now under construction with Astaldi SpA of Italy and Fe Grande of Chile as the EPC contractor. Astaldi SpA also has an equity stake in the project. It involves 6 km of tunnels between 5 m and 7 m diameter, of which 2.3 km is by tunnel boring machine (TBM) (5 m diameter).This paper outlines the local and regional geology, the scope of the Chacayes project, actual tunnel excavation rates and support, and compares the decision making on Chacayes between a choice of traditional drill and blast excavation versus TBM.The paper also outlines the next project planned to be developed by Pacifi c Hydro in the valley – the 140+MW Nido de Aguila project involving a main tunnel drive of 11 km with two intermediate adits, plus a 388 m shaft and underground powerhouse. The main tunnel drives are likely to be excavated by two hard rock TBMs (5 m diameter) but will need to be able to withstand high overburden pressures of up to 1300 m.Subsequent projects in the planning stages include the downstream Coya II project with two tunnels totalling approximately 10 km, one of which may be by TBM.

Mar 8, 2011

By Tom Snyder, John Brulia

Part I is the first of a series of articles by the authors on hazardous materials (HM) transportation safety and compliance for shippers and carriers who offer and transport commercial explosives in commerce on public highways in the U.S.

Jan 1, 2014

By W Polkowski, M Tangstad, M Wallin, J Jiao

Fe-26Si-9B (wt per cent) alloy has been identified as a potential high-temperature phase change material (PCM) due to its attractive properties, such as its high latent heat of fusion and low volumetric change during solid/liquid transition. For the successful utilisation of this alloy into thermal energy storage (TES) systems, the development of a cost-effective production method is essential. Presently, the Fe-26Si-9B alloy is produced by mixing FeSi alloys with either pure boron element or FeB alloys. However, the use of pure boron is financially prohibitive, and the carbothermic reduction results in high greenhouse gas emissions and high energy consumption in the production of FeB alloys. In this regard, our study proposes a silicothermic reduction method to produce Fe-26Si-9B PCM by using FeSi alloys and B2O3-based oxides. Accordingly, the influence of various parameters on the production process was investigated, including operating temperature, holding time, B2O3 content in the added oxides, and initial Slag/Metal (S/M) ratio. Based on the experimental results, the optimal parameters for producing FeSiB alloys with over 9 wt per cent boron were determined. Consequently, it was documented that the FeSi alloys and the added oxides enriched with 50– 65 wt per cent B2O3 should be subjected to temperatures ranging from 1550–1650°C, maintain an initial S/M ratio exceeding 1, and ensure a holding duration beyond 1 hr. Moreover, the energy consumption of this process was estimated to be ~1.86 MWh/t metal and the mass loss was lower than 7 per cent. Therefore, silicothermic reduction offers a sustainable approach for producing FeSiB alloys with a boron content above 9 wt per cent.

Jun 19, 2024

By H. M. Lewis

The current status of the international zinc market is summarized, and a supply /demand outlook is presented for the next five years. A number of technical problems facing the industry are outlined. Introduction ZINC has sometimes been called the unknown metal. Considering that on a world basis it ranks third among non-ferrous metals in production and consumption, zinc retains a certain modesty. It has no distinctive colour like copper, lacks the low density of aluminum or magnesium and is not always easy to identify as a product. The 'spangle' of galvanized steel is probably zinc's most distinguishing feature. The purpose of this article is to develop an over-all review of zinc. Starting with the current position of the metal, the major factors that will shape its future will be described so that an assessment of the outlook for zinc can be made.

Jan 1, 1978

By Carsten Gerold

The paper is giving an overview about successful operating Loesche Vertical ? Roller ? Mills (VRM) installations and summarises the main benefits of the dry compressive Loesche grinding technologies in Airflow- and Overflow-Mode. Some of these benefits are optimised energy efficiency of the grinding - classifying - circuits, increased mineral recoveries and decreased OPEX costs, at a parallel simplification of the process route. Within this paper the process values of the Loesche VRM are compared to existing or planned conventional grinding ? classifying circuits. Further advantages discovered in pilot trials and examples for new more efficient process route alternatives are given. The paper reports about production and pilot trial experiences obtained by crushing and grinding Iron Ore, Iron Ore Concentrates, Copper Shale, Copper Matte, Copper Slag, Titanium Slag, Tin Slag, Steel and Stainless Steel Slag with Loesche VRM.

Sep 1, 2012

By Robert T. MacMillan

An essentially chemical technique has been developed on a small scale for the efficient utilization of certain domestic titaniferous iron ores. Three main steps are involved: (1) Sintering the ore at 1,050° C. with carbon and soda ash to reduce the iron to metal powder, retaining the titania in the slag, (2) separating the powdered iron from the slag, after wet grinding, by magnetic or gravity methods, and (3) sulfuric-acid decomposition of the titania fraction to produce pigment and certain byproducts. The technique was first applied to the tailings from the Bureau of Mines bauxite-concentrating plant at Bauxite, Ark. A good grade of powdered iron was produced from this material. Subsequently, the work was diverted to the study of the titaniferous magnetite from the MacIntyre Mine at Tahawus, N.Y., because of the potentially higher recoveries of iron, titanium and vanadium. Ninety percent of the iron in this ore has been recovered as an iron powder analyzing 90 percent metallic iron and containing 2 to 3 percent TiO2. The remaining titania was found in the slag and was recovered as pigment-grade TiO2 by application of a suitable technique. The vanadium was distributed between the TiO2 fraction and the alkaline liquor resulting from the wet-grinding and magnetic-separation operations, with only a minor proportion retained by the metallic iron.

Jan 1, 1950

Mine drainage and mine reclamation are topics of major interest to the mining industry, federal and local governments, and the general public. This publication and its companion three volumes are the proceedings of a conference held in Pittsburgh, Pennsylvania, April 24-29, 1994. There were twelve sessions (69 papers) that dealt with mine drainage, including modeling, geochemistry, prediction, treatment, control strategies, characterization, hydrology, and case studies. These sessions comprise volumes 1 and 2. The six sessions (34 papers) that dealt with reclamation and revegetation of disturbed lands are included in volume 3. Volume 4 includes the six sessions (34 papers) that dealt with such topical issues as fires at abandoned mine sites, subsidence, hydrology, mine wastes, and policy. Poster session presentations are represented by 49 papers and 92 abstracts that have been placed in the back of volumes 2, 3, and 4, consistent with the subject of that volume.

Jan 1, 1994

By H. C. Fowler

Hydrogen sulphide associated with the gasps and vapors from certain crude oils now produced in the United States has forced a serious health and safety problem upon the petroleum industry. Although the presence of hydrogen sulphide in or occurring with Mexican crudes has been known for some time, it was not until recently that crude oils which give off poisonous amounts of hydrogen sulphide have been produced to any extent in the United State. The injurious effects of this poisonous gas were first recognized by the refiners along; the Atlantic and Gulf Coasts upon receiving shipments of crude petroleum from Mexico. The problem of combating the hazards of the gases and vapors given off by this petroleum become more important as the use of Mexican crude increased. In 1925, the Bureau of Mines and Public Health Service under cooperative agreement with the American Petroleum Institute, studied the causes rend effects of hydrogen sulphide poisoning. Bureau of Mines Bulletin 2312 is report of this investigation, and although written with special reference to refineries, it nevertheless contains much information that is of value to the producer of petroleum.

Jan 1, 1927

By JOHN HOMER, Jacob L. Carr, Jonathan K. Hrica, Kathleen M. Stabryla, Iman Benbourenane, Jennica L. Bellanca

Given the recent focus on powered haulage incidents within the US mining sector, an appraisal of collision avoidance/warning systems (CXSs) through the lens of the available research literature is timely. This paper describes a rapid review that identifies, characterizes, and classifies the research literature to evaluate the maturity of CXS technology through the application of a Technology Readiness Assessment. Systematic search methods were applied to three electronic databases, and relevant articles were identified through the application of inclusion and exclusion criteria. Sixty-four articles from 2000 to 2020 met these criteria and were categorized into seven CXS technology categories. Review and assessment of the articles indicates that much of the literature-based evidence for CXS technology lies within lower levels of maturity (i.e., components and prototypes tested under laboratory conditions and in relevant environments). However, less evidence exists for CXS technology at higher levels of maturity (i.e., complete systems evaluated within operational environments) despite the existence of commercial products in the marketplace. This lack of evidence at higher maturity levels within the scientific literature highlights the need for systematic peer-reviewed research to evaluate the performance of CXS technologies and demonstrate the efficacy of prototypes or commercial products, which could be fostered by more collaboration between academia, research institutions, manufacturers, and mining companies. Additionally, results of the review reveal that most of the literature relevant to CXS technologies is focused on vehicle-to-vehicle interactions. However, this contrasts with haul truck fatal accident statistics that indicate that most haul truck fatal accidents are due to vehicle-to-environment interactions (e.g., traveling through a berm). Lastly, the relatively small amount of literature and segmented nature of the included studies suggests that there is a need for incremental progress or more stepwise research that would facilitate the improvement of CXS technologies over time. This progression over time could be achieved through continued long-term interest and support for CXS technology research.

Jun 17, 2022

By F. S. Crawford

The wide variation in the medical facilities, type of accident reports and provision for the welfare of employees, in addition to the compensation provided by the various State laws,- was -studi-eci, by the.. wri-ter in the Lake .. Superior_ r.egion . .. - -Several cDmpanies f~rnished. the information which follows. Names have been omitted , ~ut the information should be of .intere·st to companies desirous of improving t_his branch of thej..r accident-prevention work. : . . --Because a summary of the metho.ds used would merel:y: result in _ a.n a.ttempt to set _up an ideal, it was concluded that in preparing this paper a statem.ent .of_ tbe individual methods of -each company wou-l d .b-e .Qf .. the most inte-res.t, . and the.y h~ve . been .. li.steq with .no regard to the size of the company . . ··· -In the - appendix are -a -number of report. forms used by .various _operators for reporting accidents to t he company and .to the State. These are self- explanatory. and many a re mentioned in -the body of circu-1-ar-.

Mar 1, 1932

By Aditya Rana, A. K. Mishra, M. M. Singh, N. K. Bhagat

Many cases of derailments, train accidents and traffic interruptions due to the slope failure and rockfall have been reported in the past on Konkan Railway trackline because of unstable rock slopes. The authorities installed stability enhancement measures such as wire netting, rock bolting and shotcreting which were found insufficient. The failed geotechnical measures prompted authorities to excavate the unstable slopes. Rock blasting is generally not preferred for the excavation of slopes along the transportation route. Stabilisation and widening of slopes by blasting need closure of the route for a considerable time. Discontinuing traffic on Konkan Railway route was undesirable as it connects two important port cities Mumbai and Mangalore. The paper presents an innovative directional controlled blasting (DCB) technique for excavating three unstable slopes (i.e. cuttings) in hilly terrain without disturbing the traffic. New empirical formulae for small geometry blasting to estimate burden and throw have been developed. A unique sequence of firing and excavation with powder factor varying between 0.04 and 0.39 kg/m3 irrespective of the actual free face was used for rock blasting. The process controlled the throw of blasted material over the track and resulted in a smooth and stable wall. The slope angle has been changed from 80 to 82° to 45–47° and probability of wedge, planar and toppling failures was eliminated. About 100 such accident-prone slopes (52 km cumulative length, 7% of total route) situated at discrete locations along Konkan Railway route were stabilised using the technique. No incident of rockfall and slope failures along these slopes has been observed after the stabilisation.

By Bruce F. Grant

"INTRODUCTION The future of oil production in the part of the Appalachian region included in southwestern Pennsylvania; West Virginia, and southeastern Ohio is directly dependent on the maintenance of existing wells. This report presents an analytical study of the methods used in oil-well reconditioning in this area. The study is part of a research program designed to evaluate those means of stimulating oil production that can effectively and economically maintain present oil-production rates and make it possible to keep existing wells in operation. Well-reconditioning work was curtailed during the war; therefore, an abnormally large number of wells in the Appalachian Region is now in need of repair. Because the lubricant content of Appalachian crude: oils is high and the refined lubricating oils an; particularly suited to use in high speed, high-temperature engines, the demand for these crude oils during the war exceeds, the maximum rate of production obtainable under wartime operating conditions. Increases in operating, expenses, inability to meet war-time reconditioning costs, and inflexible price structures caused the abandonment of an alarming number of wells during the past 4 or 5 years.As a means of increasing regional oil-production rates, new drilling in the older fields for primary production generally is uneconomical because reservoir pressures in most of the fields have virtually been depleted and the production rates of newly drilled wells are small."

Feb 1, 1948

Problems caused by water discharge from surface mine ventilation shafts can be significant and are usually unforseen. The discharged water is often hyper-saline or acidic and can cause environmental degradation over a wide radius. It can also lead to recurring power pole fires and primary fan breakdowns. A range of solutions to the water discharge problem has been implemented in many Australian mines. In most cases the solutions have been ad hoc, with the overall cost and effectiveness varying tremendously. This paper reviews and contrasts the practicality and effectiveness of the various available remedial options.

Jan 1, 2002

By Doug Harding

The Metropolitan St. Louis Water District’s Project Clear is a 28-year program targeting wastewater capacity throughout St. Louis, MO. The extensive program includes the Jefferson Barracks Tunnel, running parallel to the Mississippi River at 2 m ID and 5,400 m long. A rebuilt Robbins Main Beam TBM began boring but hit challenging conditions about 2,400 m in, including water inflows. A larger 4.1 m Robbins Main Beam machine will complete the remaining 3,050 m in limestone, dolomite, and shale. The TBM will utilize a high-powered, high breakout torque cutterhead along with enhanced 360-degree probing & grouting capabilities to detect any karst formations.

Dec 1, 2022

By W. B. Plank

I HAVE been asked by the Chairman of the Engineering Education Committee to outline what the engineering colleges would like the mining companies to do with the young engineer just, out of college. It has been suggested that, because my own personal experience has been almost entirely within the coal industry, I handle this subject from that view- point. Many thoughtful engineering educators are today wondering what effect the present employment policies of many industrial companies are going to have on the young man just starting out in his profession. Since before the World War large industrial concerns, such as those in the electrical and mechanical industries, have gone to the colleges to interview 'likely graduates until today there has developed in most of our engineering colleges, especially in the eastern part of the country, what appears to be a lively competition on the part of these companies in bidding for the young graduate engineer. The employers of mining engineers, with one or two exceptions, have not yet begun to enter this competition. It remains to be seen how serious this situation will become, how it will affect the training of other engineers, and what effect, if any, it will have on the mind of the young man about to enter college who may be inclined to take up mining engineering, but who gains the impression from this well advertised employment service just mentioned that there is no opportunity for him in the mineral industry as com- pared with the opportunities offered in say civil, mechanical, and electrical engineering.

Jan 1, 1929

By M. Panayotova

Most of the quantity of the water soluble xanthates, used in mineral flotation, is consumed in the process. However, the residue amounts are water contaminants downstream the mineral processing operations and can be toxic to aquatic biota at concentrations of 1 mg/L. In order to be able to discharge water from tailing ponds to natural water bodies the concentration of xanthates has to be decreased. The present paper studies the uptake of potassium ethyl xanthate by directly modified with copper and lead ions natural zeolitic rock, without passing through zeolite transformation into homoionic form. Modified zeolite exhibits high, comparable with powdered activated carbon of chemical purity grade, capacity to remove potassium ethyl xanthate from model wastewater, with pH in the range of 7?9 and pollutant concentration in the range of 10-150 mg/L. The pollutant immobilization is fast. Both Cu and Pb modified zeolite behave as selective with respect to xanthate in the model wastewater, and Cu-modified zeolite possesses higher selectivity. The equilibrium is best described by the Freundlich equation. Keywords: xanthate, wastewater, modified zeolite

Sep 1, 2012

By Robert Bell

THE " Tar-Sands." is the name which has been given to the extensive horizontal deposit of fine Cretaceous sand, blackened by tarry petroleum, which forms the banks of the last or lowest 130 miles of the Athabasca river before it terminates in Athabasca lake. The Cretaceous strata, to which these sands belong, extend northwesterly from Dakota all the way to this lake and for 500 miles beyond it. The Athabasca river forms the uppermost section of the Athabasca-Mackenzie, one of the great rivers of the world. It rises on the Pacific side of the Rocky mountains, westward of Edmonton, and flows north of east to a point called Athabasca. Landing, 100 miles north of Edmonton, where it turns northward and runs about 280 miles before it falls into the west end of Athabasca lake. The section of this river-system which discharges the lake just named into Great Slave lake, is called Slave river, and below the latter lake it becomes the Mackenzie river. Along the section of 280 miles of the Athabasca river above mentioned, the Cretaceous strata consist of bluish-gray and drab-gray marls, on top, from Athabasca Landing to Drowned rapid, 110 miles down stream; then heavily bedded gray sandstones, 225 ft. in greatest thickness, underlying these, form the banks for about 40 miles further. The strata appear to be horizontal, but they really clip very slightly to the southward. At Drowned rapid, we see the first of the tar-sands resting on almost horizontal beds of bluish-gray limestone of Devonian age. In some places the limestone is associated with shaly or marly bands. Notwithstanding the great hiatus between the two series, the horizontal tar-sands lie conformably upon the almost level upper beds of the limestone wherever the two formations are seen together, all along the river, throughout a

Mar 1, 1908

By D. E. G. Maschmeyer

The operation of the pilot plant for the S-C Copper Process during 1976 has provided the basic data for the design of a commercial-scale plant. This paper introduces the commercial aspects of the S-C Copper Process through the presentation of a process flow diagram, a schematic flow diagram and basic design parameters for 75,000 tonnes per year (tpy) copper rod production from chalcopyrite concentrate. Basic operating requirements are outlined and a preliminary estimate of operating and capital costs for a Western Canadian location are summarized. The results have been compared with a modern smelter/electrorefinery to highlight the advantages and disadvantages of these two alternatives and to show why the new S-C Copper Process technology should be of interest to the copper industry.

Jan 1, 1978

By M. Pearson, L. Zunti

Pressure vessels in hydrometallurgy and many chemical process industries throughout the world require the use of specific lining systems to protect the parent vessel materials from corrosion and/or abrasion. Typically, these lining systems are required for processes that are corrosive and operate at elevated temperatures. Two basic lining system types arc: 1) refractory linings in conjunction with an impervious corrosion resistant membrane, and 2) metal-clad vessels consisting of titanium or other corrosion resistant metal bonded to a carbon steel shell. Operating conditions play a key role in selecting the type of lining system to be utilized for a specific application. Lining systems in turn have an impact on the process vessel size, which ultimately affects the capital cost of the vessel. The capital costs for each type of lining system must be considered for each application, as well as maintenance concerns, quality control, and delivery. It is clear that operating conditions play a key role in the final selection of lining systems utilized for specific projects based on initial capital cost, life-cycle maintenance costs, and overall service life. This paper will examine the fundamentals of each lining system, their inherent technical strengths and weaknesses, and present relative cost comparisons for each lining system as they apply to specific operating conditions and vessel sizes.

Jan 1, 2004

By Arno C. Fieldner

Six years ago, I addressed the annual meeting of the American Society for Testing Materials on "Fuels of Today and Tomorrow."3/ Since then, our country has been drawn into another great war of veritably global extent, with unprecedented demands on fuels, foods, and materials in general. My purpose in this address is to review the changes in fuel supply and demand since 1937 and to give you my views on the outlook for the future. CONDITIONS IN. 1237 Daring 1936 the United States produced and consumed one-third of the world production of coal, two-thirds of the petroleum, and about 95 percent of the natural gas. Two-thirds of the oil produced in all countries since the discovery well was drilled in 1859 had come from American wells. With the exception of the three depression years 1931, 1932, and 1933, new oil reserves were being discovered since 1924 well in excess of our increasing rate of consumption. Discoveries of natural gas, likewise, were tremendous in volume, and this fuel was being transported to most parts of the country by pipe lines; some of them more than 1,000 miles long. We had all kinds of mineral fuels in abundance and at prices that did not stint anyone in the maximum utilization of the mechanical devices that were being developed on every hand. No one suspected that the time might come in a few years when, gasoline would be doled out to some of us at the rate of 1-1/2 gallons a week or that many of our fuel-oil furnaces would have to be converted to burn coal. Of course, these restrictions are due to unusual war conditions, such as lack of coastwise tanker transportation, unprecedented demand for aviation gasoline, and the shortage of rubber for automotive tires. However, these shortages do call our attention to the vital part of petroleum reserves in our country's future position among nations. Therefore, it is of special interest to review briefly the relations of recent supply and demand with respect to our various mineral fuels.

Jan 1, 1943