Search Documents

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine or the expansion of an existing mine can range from nine to 24 months, or even longer. The time frame will vary depending on whether an environmental assessment (EA) or an environmental impact statement (EIS) will be completed Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. In this paper, a two-year natural resource baseline study by Homestake Mining for the Ruby Hill Mine, Eureka County, NV, is used as a case study to describe how a properly designed and executed natural resource baseline study streamlined the NEPA process.

Jan 1, 2003

Introduction The Homestake Mining Co. has always been big on gold. After 108 years in the business, the company and its principal product are almost synonymous. The relationship continues. On Sept. 28, 1985, Homestake held formal dedication ceremonies for its newest gold mine - McLaughlin. The McLaughlin open-pit operation is located in northern California, some 113 km (70 miles) northeast of San Francisco. It lies near the boundaries of three counties - Napa, Yolo, and Lake - and a portion of its facilities are located in each. McLaughlin was originally the site of the Manhattan mercury mine that produced nearly 80,000 flasks of the quicksilver from the 1860s to 1978. At the September dedication, Homestake renamed the mine in honor of the late Donald H. McLaughlin. McLaughlin was with Homestake for nearly 60 years. He rose from exploration geologist to his ultimate positions of chief executive officer, director, chairman of the board of directors, chairman emeritus, and chairman of the executive committee. The discovery of the McLaughlin deposit occurred in 1978, the last year of operation for the Manhattan mine. Homestake geologists used a newly developed model and found surface gold at the mine site. That same year, Homestake signed an agreement with the property owner and began a two-and-a-half year exploration program. An initial discovery announcement of 31.1 t (1 million oz) of gold was made in 1980. In 1981, this was revised to 93.3 t (3 million oz), or 18 Mt (20 million st) of ore grading 5.2 g/t (0.152 oz per st). Expected mine life is 20 years. Construction began in September 1983, following the issuance of stage one permits. Start-up of operations took place in early 1985 and the first gold-silver dore bar was poured on March 4. Since then, more than 540 kt (600,000 st) of ore has been milled, producing about 1.6 t (50,000 oz) of gold. Of special interest at McLaughlin is the use of three autoclaves for gold extraction. According to Homestake, this is a first. The autoclaves are designed for a 90% gold recovery rate. Early results have proven yields at this rate and higher. Geology The McLaughlin deposit is about 1.5 km (5000 ft) long. It occurs as a wedge-shape, narrowing to a verti-

Jan 1, 1986

By J Carter, B J. Armstrong

Best practice for the submission of samples to an internal or commercial laboratory requires quality control materials to be included for the purpose of independently and comprehensively assessing laboratory performance. These quality controls include the use of certified reference materials (CRMs) and may be blind to the laboratory. Iron ore companies purchase these materials from reputable manufacturers from stock of run-of-mine materials at the appropriate grades. The international standard, ISO 17034 (ISO, 2016), specifies the competency requirements for organisations manufacturing reference materials, and includes rigorous requirements for the assessment of homogeneity, stability and establishment of property values and their uncertainties. Homogeneity is one of the most important measures of suitability for all certified reference materials and refers to the degree to which the composition and properties of a sample are uniform throughout the batch, relative to the analytical precision of the method. More specifically, homogeneity studies of candidate reference materials should be assessed for both within sample variance and between sample variance with appropriate statistical controls. The design and application of homogeneity studies are discussed as they apply to both crushed and pulverised reference materials. Crushed certified reference materials have been utilised by the iron ore industry for a number of years and provide the user with a critical assessment of variances in sample preparation in addition to analysis. Crushed reference materials are similar in presentation to an RC sample and are generally used as discrete parcels of material submitted to the laboratory from the field. Pulverise certified reference materials miss the sample preparation step and are subsampled from th delivered sachet at the point of analysis. This paper compares the relative homogeneity performance of crushed and pulverised certified reference materials by grade across key iron ore chemical constituents. Outcomes are benchmarked to the international standard ISO 9516 (ISO, 2003) for the determination of various elements in iron ores by lithium borate fusion and X-ray fluorescence. Practical implications are discussed with reference to a case study from an iron ore laboratory in the Pilbara.

Sep 18, 2023

By Xiang Sun

Microwave processing has been under continuous development as an advanced heating method in modern industries. However, problems with uneven heating still remain. Although heating uniformity is highly dependant on the properties of the materials being heated, proper furnace design to prevent uneven field distribution is another important factor. As an alternative to experimental measurements and adjustments to find appropriate furnace parameters, computer simulation is a convenient method for modeling, understanding, and improving the uniformity of microwave heating. This paper discusses current modeling technologies as well as applicable techniques for improving microwave heating uniformity. The purpose is to give a basic understanding on how to find, analyze, and minimize the problems associated with uneven heating in microwave processing.

Jan 1, 2006

By Gordon R. Luster

Mineral-processing plants commonly rely on homogenization and proportioning facilities to reduce the variability of incoming raw materials and to blend different materials together to satisfy quality specifications. To determine appropriate designs for these facilities, plant designers need information about the variability of the mined materials, measured as the materials enter the plant. But if the materials to be mined in the future differ greatly from those used in the past, only information extracted from exploratory drilling of the materials in the around may be available. Fortunately, useful information for plant design may still be obtained by combining simulated mineral deposits with simulations of likely mining procedures. The output of a mining simulation is a time series of simulated raw-material characteristics that should mimic the behavior of the real materials to be delivered to the plant in the future. This paper shows how conditional simulations of coregionalized ore grades can furnish information useful in the design of homogenization and proportioning systems.

Jan 1, 1986

By P. Massacci

This study deals with the development and utilization of computer models for evaluating the extent to which variability of raw material grades can be reduced from the deposit to the processing plant. The specific case of a cement works is examined. The deposit and the elementary quarring operations were modeled for the medium and long-term planning of production with the objective of predicting grade variability of the flow stream in time. The feeds inferred from previous modellings were used for simulating storage operations. In particular, the storage process (linear stockpile, as an alternative, blending from various heaps) was modelled in order to select the main parameters of the process to minimize grade variations of the feed to mill. The ways followed for modelling the prehomogenization process are described. The homogenization performance and efficiency in the silo stage has also been studied and an estimate made of the distribution of residence time on the basis of input and output sampling.

Jan 1, 1986

By M. R. Dion, K. Frenette, R. K. Jonas, S. Simard, F. Robichaud

"In 2011, a site study indicated that the application of Honeywell’s Multivariable Predictive Control Technology (MPC) to the Goldex processing facility would provide significant opportunities for improvement. Grinding MPC was implemented in the SAG Mill in June 2015. This pilot application, called Phase 1, featured one of the first Multivariable Predictive Controllers to be installed in a Canadian mineral processing plant. Since the implementation of MPC, gold recovery from the gravity circuit has increased. MPC contributed to a decrease in flotation feed particle size (120 to 112 µm) and an increase in the SAG feed tonnage (8.5% increase). MPC also increased and stabilized the % solids of the SAG feed, which can have an impact on cost reduction (mechanical maintenance). Additionally, MPC increased productivity, providing grinding operators with more time to perform other tasks. Further anticipated benefits include the standardization of the grinding circuit operation from one team to the next, thereby minimizing circuit disturbances resulting from different operating philosophies. This paper will discuss the advanced control project development and justification, the technology and rapid implementation process, the performance results and the benefits obtained.IntroductionGoldex is an underground mine located near Val-d’Or that is owned and operated by Agnico Eagle Mines Limited (AEM). Between 2008 and 2011, mining focused on the Goldex Extension Zone (GEZ). In 2011, the project was halted due to geotechnical problems; operations ceased until late 2013. Goldex operations resumed in September 2013 with the M and E zones, for which there were 0.7M gold ounces of proven and probable reserves, 2.1M ounces of measured and indicated resources and 1.2M ounces of inferred resources, totalizing 4M ounces. Life expectancy was extended until 2024."

Jan 1, 2017

By Massimo Concilia, Remo Grandori, Paolo Nardone

Paul Y. – SELI Joint Venture had been contracted to build the longest section of the Strategic Sewage Disposal Scheme (SSDS) – Stage I. This involved two tunnels under urban and marine areas excavated by high performance hard rock open type TBMs operated from deep shafts. A specific ground treatment program was developed using advance probing and grouting to control water inflow into the excavations. The article describes: the technologies adopted, the experienced problems, the encountered productions and their interrelation with the water inflow amounts, the possible improvement in the technologies for the excavation of the future stages of the same project as well of any other project under similar conditions.

Jan 1, 2001

By Will Foreman, Douglas D. McLearie, Edwin K. H. Tong, William H. Hansmire

Hong Kong’s Strategic Sewage Disposal Scheme (SSDS) Stage I involves the provision of a system of deep tunnels for transporting to a central treatment works wastewater collected from a number of catchments around Victoria Harbour. For the SSDS Stage I works, about 24 km of tunnels have been excavated in hard rock at depths ranging from about 80 to 150 m below Victoria Harbour and the surrounding heavily developed areas of Kowloon and Hong Kong. Five tunnel boring machines(TBMs) with diameters ranging from 3.2 m to 4.3 m were used to excavate the tunnels. Tunnel excavation has been completed and tunnel linings are in progress. Major tunnelling issues such as ground stabilisation and water control encountered in the project are summarised. An overview of one of the possible future tunnel systems that might be adopted in subsequent stages of SSDS is also presented.

Jan 1, 2001

The Honor Roll includes the names of all members of the Institute Whom we know to have been on active military duty it the date of compilation, Mar. 5, 1919. Despite our efforts to have this list accurate and complete, some of our members who have been rendering military service are probably left off because of the fact that we have not been informed of their military connection. The list of men in military service has been compiled with great difficulty owing to the modesty of the members, who in their patriotism began their service but neglected to send us notice. In 1918, We published a separate Honor Roll of the Institute in which we included a list entitled "On active duty in other departments of the service" which contained the names of members who were rendering important emergency service to the Government other than in the Army. This list is entirely omitted this year because any list We might compile for this purpose would be entirely inadequate and must inevitably do injustice to a large number of our members who have been devoting great time and making many sacrifices for the benefit of the government along lines not within our ken. It is not too much to say that almost all our membership in this country has been, more or less directly, doing its uttermost for the successful prosecu¬tion of the war. The active work of many of these members we are Well aware of, as is also the rest of the civilized world. Faithful and wholehearted efforts on the part of many other members we have not been informed of, so that any list would be both incomplete and unsatisfactory.

Jan 1, 1923

Jan 1, 1925

1913. FRANDKA WBONA DAMS Montreal, Canada. 1921. WILLIAM CUTHBERTB LACKETT Sacriston, Durham, England. 1923. GELASIOC AETANI. Rome, Italy. 1929. TAKUMAD AN Tokyo, Japan. 1920. HENRYS TURGISD RINKER. Merion Station, Pa. 1922. FEDERICGIOO LITTI. Torino, Italy. 1906. SIR ROBERTA . HADFIELD. London, England. 1928. JOHNHA YSH AMMON.D. New York, N. Y. 1921. FRANKW ILLIAMH ARBORD London, England. 1917. HERBERTH OOVER. Washington, D. C. 1906. HENRI LECHATELIER. Paris, France. 1900. WALDEMAR LNDGREN Cambridge, Mass. 1879. JOHNM ARKLE .New York, N. Y. 1921. C. MCDERMID London, England. 1913. EZEQUIELO RDONEZ Mexico City, Mexico. 1909. ALEXANDRPEO URCEL Paris, France. 1911. ROBERT H . RICHARDS Cambridge, Mass.

Jan 1, 1929

THE John Fritz Medal Board of Award, at its regu¬lar annual meeting Oct. 19, awarded its gold medal to Herbert Clark Hoover. Thus ended a process of selection begun a few years ago. The award was tentatively made a year ago by the Board, which is composed of sixteen recent past-presidents of the four national societies of Civil, Mining and Metallurgical, Mechanical, and Electrical Engineers, having together a membership of nearly 60,000. The sixteen members of the Board are: American Society of Civil Engineers : C. E. Grunsky, Robert Ridgway, George S. Davison and John F. Stevens ; American Institute of Mining and Metallurgical Engineers: William Kelly, J. V. W. Reynders, Samuel A. Taylor and E. DeGolyer; American Society of Mechanical Engineers: Fred R. Low, D. S. Jacobus, Dexter S. Kimball and Charles M. Schwab; American Institute of Electrical Engineers: Farley Osgood, M. I. Pupin, C. C. Chesney and Bancroft Gherardi.

Jan 1, 1928

By AIME AIME

THE portrait of Herbert Hoover, President of the United States, recently painted by Philip A. de Laszlo at the request of the four Founder engineering societies, was unveiled at a special meeting in the Engineering Societies Building on Feb. 15. The portrait was delivered by Gano Dunn, chairman of the Hoover Medal Board of Award, who said, in part:,

Jan 1, 1932

By Stephen P. Quin

One of the most prospective undeveloped greenstone belts in Canada, the Hope Bay greenstone belt extends over 80km in a north-south direction and is between 7 and 20km wide. The belt lies on the arctic coast and comprises mafic meta-volcanic and meta-sedimentary rocks that are bounded by Archean granite intrusives and gneisses. The greenstone package has been deformed during multiple events and is transected by major northsouth trending shear zones that appear to exert a significant control on the localization of mineralization. The Hope Bay belt contains a number of significant gold deposits hosted in a typical Archean greenstone belt and which occur in several geologic settings, including shear-hosted, lode-style and breccia-associated. Combined, the deposits host a measured and indicated resource of 1.6 million oz of gold averaging 15.7 g/t plus an inferred resource of 2.7 million oz of gold averaging 12.3 g/t. All deposits remain open to expansion. Exploration in the period 2000-2002 by Miramar includes more than 110,000m of drilling to more fully define the nature of the known deposits, while regional exploration has focused on identifying and evaluating new targets. In carrying out its programs, Miramar uses a number of techniques to improve its chances of exploration success. Activity in 2003 includes 43,000m of drilling focused on expanding resources in the Madrid area, testing the Boston deposit at depth and continuing the hunt for more discoveries. Meanwhile Miramar is advancing one of the deposits towards a production decision, based on a low capital, high return development scenario.

May 1, 2003

By I. R. Muirhead, A. L. Craven

The trend in mining thermal coal is only to mine coal with the lowest sulphur content. In many coal seams, bands of coal with high sulphur content are often present, generally occurring either at the roof or floor level. Methods of selective mining are, therefore, necessary to recover only the low sulphur coal. This paper examines the methods currently in use in mines and the alternative methods that are able or have potential to offer control of shearers and continuous miners where greater thicknesses of coal have to be left in the roof and floor. These alternative methods rely on such characteristics as neutron gamma radiation; electromagnetic waves; vibration; infrared; infrared; optical; pick force; X-ray fluorescence; conductivity; gyroscopes and laser systems.

Jan 1, 2000

By Ray Brainard, Adriana Ventimiglia, Amanda Kerr

Preliminary design is underway for a new Southern Nevada Water Authority (SNWA) project that will ensure one of America’s most reliable water systems by providing continued, reliable water service to existing and future customers. The Horizon Lateral is a $1.6 billion water transmission pipeline that includes 7–10 miles of 108-inch finished diameter rock and soft-ground tunnels. The tunnels will traverse volcanic rock in or around the McCullough Mountain Range and the surrounding alluvial basin. The tunneling community will find relevance in hearing about this critical infrastructure project from a leading wholesale water utility owner with a proven track record for on-time, collaborative projects.

Dec 1, 2022

We outline a first version of an ambitious goal: The world's first horizontal (matrix-independent) generic sampling standard. The specific needs and requirements are overwhelming, as all the world's analytical standards follow strict matrix or material type classification pigeonholes, leading to a plethora of analytical standards. One could rightly expect a similar multiplication regarding sampling standards, yet the singular HORIZONTAL is aimed at being truly generic. Also the existing style of standards writing is cumbersome and partly contradictory. The current work is presently being pursued in CEN and European Union standardisation regimens, for which reason full disclosure and publication is not allowed. Respecting this constraint, we unofficially present selected key issues involved in developing HORIZONTAL: The objective and scope of a horizontal sampling standard is to delineate the minimum set of principles and procedures needed to guarantee documented representative sampling for all types of materials. The horizontal standard is designed for two types of use: 1. auditing/assessing/ improving the reliability of an existing sampling procedure, and 2. design and implementation of a new sampling procedure (new lot type). The principles in this standard are all derived from the Theory of Sampling (TOS), but the standard is far from a mere collection of TOS principles. Representativeness is a characteristic of the sampling process, not of samples themselves. For practical purposes, the horizontal standard follows the fundamental distinction between 'stationary lots' (0-D, 2-D, 3-D lots) and 'dynamic lots' (within TOS aka process sampling - including extended, non-moving 1-D lots). TOS' principles of 'correctness' must never be broken at any stage, lest representativeness is irretrievably lost. The horizontal standard is not written in the mandatory fashion for legally binding matrix-specific standards, eg ISO - for the present overarching purpose a different style had to be developed. The standard must be immediately understandable in full, which merits special demands, eg extensive use of didactic illustrations. HORIZONTAL introduces an all-inclusive sampling variability measure, Relative Sampling Variance (RSV) which is for sampling of stationary lots as variographics is for process sampling - RSV is to be used as a quality criterion for any stationary sampling procedure as applied to a specific heterogeneity (lot/material). The target for this standard is all individuals, companies, organisations and regulatory bodies who are responsible for sampling: technicians, process engineers, laboratory personal, academic and industrial scientists as well as project leaders, technical managers/directors and top managers. Based on current R&D we illustrate the principles promulgated by HORIZONTAL with cases from exploration and mining of minerals commodities, a Finnsh 'Autosampler' at work in the mining context (RSV) as well as sampling equipment for use in the cement and mineral commodities industries. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Mar 1, 2010

By J. D. Potts

Installation of a horizontal air blocking shelf around the inside perimeter of the surface mining drill deck shroud is proposed to improve dust capture. Without the use of this shelf, a strong coanda effect airflow pattern results in dust leakage to the environment, especially at the shroud-to-ground interface. Bailing air exits the drill hole and travels along the drill steel to the underside of the table, where it fans out across the bottom of the drill table and continues down the sides of the shroud. This dust-laden bailing air then strikes the ground and fans out under gaps between the shroud and the ground. The proposed shelf prevents dust-laden air from striking the ground by redirecting it toward the center of the enclosure, where it can be captured. Laboratory tests demonstrated that the shelf reduced dust levels outside of the shroud by 81% under operating conditions consisting of a 1.9:1 collector to bailing airflow ratio, and a 5.1-cm (2-in) gap between the shroud and ground. The shelf was 15.2-cm (6-in) wide and located at a height equal to 2/3 the distance measured from the bottom of the shroud to the bottom of the drill table. The air blocking shelf was also capable of overcoming the adverse impact of vertical leakage along the shroud seams as long as this leakage was confined to an area below the horizontal plane defined by the shelf location.

Jan 1, 2009

By Potts J. D.

Installation of a horizontal air-blocking shelf around the inside perimeter of the surface mining drill deck shroud is proposed to improve dust capture. Without the use of this shelf, a strong Coand? effect airflow pattern results in dust leakage to the environment, especially at the shroud-to-ground interface. Bailing air exits the drill hole and travels along the drill steel to the underside of the table, where it fans out across the bottom of the drill table and continues down the sides of the shroud. This dust-laden bailing air then strikes the ground and fans out under gaps between the shroud and the ground. The proposed shelf prevents dust-laden air from striking the ground by redirecting it toward the center of the enclosure, where it can be captured. Laboratory tests demonstrated that the shelf reduced dust levels outside of the shroud by 81% under operating conditions consisting of a 1.9:1 collector-to-bailing-airflow ratio and a 51-mm (2-in.) gap between the shroud and ground. The shelf was 152-mm (6-in.) wide and was located at a height equal to 2/3 the distance measured from the bottom of the shroud to the bottom of the drill table. The air-blocking shelf was also capable of overcoming the adverse impact of vertical leakage along the shroud seams as long as this leakage was confined to an area below the horizontal plane defined by the shelf location.

Jan 1, 2008