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By C Roche, G M. Mudd

The Morobe Province of central Papua New Guinea (PNG) has been mined for gold for nearly a century, although it is only in the past decade that large-scale modern mining commenced. The Hidden Valley gold-silver project began construction in mid-2006 and production by August 2009, and is located in the mountains above Wau in the headwaters of the Watut River. The mine is owned and operated by the Morobe Mining Joint Venture (MMJV), which also owns the Wafi-Golpu project, comprising the Wafi gold deposit and Golpu copper-gold deposit, situated in the Watut River Valley. Together they represent a potential mine of the scale of Ok Tedi or Bougainville or bigger. The MMJV is owned in equal shares by Newcrest Mining from Australia and Harmony Gold from South Africa. Although Hidden Valley was the first large-scale mine in PNG to engineer and build a tailings storage facility, poor environmental management during construction and early operations led to significant erosion of waste rock and sedimentation impacts throughout the ~200 km length of the Watut River. Since then, substantial efforts have been made to improve environmental management, especially waste rock placement and storage and water quality management. While the impacts from the Hidden Valley project appear to be reducing, the saga has heightened concerns by many along the Watut River and across PNG about ongoing impacts from mining.This paper presents the results of an ongoing project in the Morobe Province conducted by the Mineral Policy Institute examining the historical, current and future impacts of mining, including community views, social and environmental impacts and the monitoring and regulation of mining. Overall, there is a clear need to more fully integrate social and environmental issues into life-of-mine planning and go above and beyond regulatory requirements. In this way, some of the lessons learnt – by the community, MMJV and government – can be incorporated before, during and long after mining.CITATION:Mudd, G M and Roche, C, ?2014. Mining in Morobe, Papua New Guinea – impacts, assurance and self-determination, in Proceedings Life-of-Mine 2014 , pp 313–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By R. O. Neal, G. St. J. PERROIT

As natural gas is a waning resource in many places, increased interest has attached to the use of gas for the manufacture of carbon black. Because of a large number of requests for information on the subject, the Bureau of Mines has undertaken a detailed study of the carbon-black industry, covering the mechanical details of commercial methods, with the purpose of increasing the recovery of carbon black by such processes. A study has been undertaken of the economic factors governing the carbon-black industry, the uses and properties of carbon black, the dE)velopment of more Itccurate methods of testing carbon black, microscopic examination of different grades of black, physicochemical study of methods' of mQ.nufacture now in use, and research on new methods of manufacture. Part I of this paper covers the engineering and economic side of the industry; the other phases of the investigation which have been under the direction of G. St. J. Perrott, of the Pittsburgh station.of the United States Bureau of Mines, are discussed in Part II.

Jan 1, 1922

By A Liu, T Ren

Gas explosion in underground coal workings can pose a serious threat to the safety of mine workers and the entire mine operations. Gas explosion is a very complex thermal-chain reaction in a confined underground environment. Based on combustion and explosion theory, three dimensional (3D) computational models were developed to simulate mine gas explosion flame and overpressure wave propagation in a single entry gateroad in underground coalmines. Six different explosion scenarios were modelled and compared with large scale experimental results and AutoReaGas simulations. Model validations show that the use of shear-stress transport (SST) k-? model together with eddy-dissipation model (EDM) produces good agreement with both experimental and AutoReagas simulation results. Modelling results demonstrated that the changes of temperature versus time can be divided into four stages, ie the initial condition stage, and periods of warm-up, active burning, and burnt-out. Assuming a limited volume of methane is involved in the explosion, the maximum temperature decreases as the distance increases from the explosion point, with the highest temperature reaching about 2460 K. Modelling results show that the evolution of the explosion flame shape experiences four typical stages, ie spherical flame, finger-shape flame, flame with the skirt touching the side walls (ribs) and tulip flame, which are similar to the pattern of a duct explosion. The pressure in the gateroad remains the same as the initial value before the arrival of the explosion wave and then increases rapidly to the maximum value. Modelling results from this study will be used for the design of explosion arresting devices and mine seals in underground coalmines.CITATION:Liu, A and Ren, T, 2017. Computational simulation of gas explosion and its propagation in single entry gateroad, in Proceedings Australian Mine Vent Conference 2017, pp 181–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By W. K. Gowans

The Sullivan Concentrator treats a complex sulphide ore consisting mainly of galena, marmatite and pyrrhotite. The ore carried minor values in silver, antimony, bismuth, indium and tin. The products of the concentrator are lead, zinc, iron and tin concentrates. The minor metal values other than tin are recovered from the concentrates by the refining processes in the smelter at Trail.The concentrator was completed in 1923 and first operated with a capacity of 2,500 tons per day. In the years 1926 to 1929 changes to equipment and buildings brought the operation up to 5,500 tons per day and then, in the years 1935 to 1945, the daily tonnage was raised to 8,500 tons. After 1945, the rising insoluble content of the ore made it necessary to consider the construction of a Sink-Float plant. At this time consideration was also given to the construction of a new crushing plant underground to replace the rolls crushers and cone crushers located at the concentrator. By 1949, construction of the Sink-Float plant was completed along with a new underground crushing plant, and an electric haulage way between the underground crushing chamber and the Sink-Float plant. The ore was hauled in forty 14-ton car trains which discharged into a 3,000 ton receiving bin by means of an air operated five car rotary dumper. With the start up of the,Sink-Float plant, a 1 ½ ft. by 12 ft. Hardinge rod mill was also brought into operation. The Sink-Float plant made it possible to treat 12,000 tons/day of mine run ore with up to 40% of this being rejected as float.

Jan 1, 1975

The effect of conditioning energy input on the metallurgical results of an emulsion flotation process has beenattributed by previous authors to a detergency process.This paper shows that such a process does not explain the data and that an attrition mechanism is more appropriate.

Jan 1, 1970

By Catherine T. Aimone-Martin, Meyers Joseph A.

A new strain-based criteria is being adopted for rock blasting in New York City (NYC). This criteria is based on several years of research involving vibration measurements of tall structures during blasting within several feet from buildings designated historic and Landmarked. This research has demonstrated that tall, heavy structures show little upper-structure vibratory response during hard-rock, urban blasting carried out in NYC. The Fire Department of New York City (FDNY) permits rock blasting and regulated limits for ground vibrations using the U.S. Bureau of Mines (USBM) safe blasting criteria. However, these regulations are often superseded by a 0.5 in/s (12.7 mm/s) limit imposed by the New York City Department of Buildings for historic and Landmarked buildings that are adjacent to the majority of blasting projects in the City. This onerous limit is often exceeded resulting in frequent stop work orders that increase the cost and time of rock excavation projects. The

Jan 1, 2019

By R. Stenne

This paper presents the trends in deep foundations in Europe, both in terms of design and construction. Eurocode 7 which is a design code for geotechnical engineering will be introduced in the European Union member countries, and will oblige geotechnical engineers to abandon traditional methods based on a global factor and adopt a new approach based on partial factors of safety. Execution codes (for construction of foundations and other geotechnical processes) are currently being introduced without problems. Ever more demanding environmental constraints push foundation contractors to adapt old techniques and develop new ones to comply with new regulations.

Jan 1, 2000

By Reno M. Pappas, Christopher Mark

This report presents results of a U.S. Bureau of Mines study of longwall gob material. The objective of this work was to determine material stiffness properties of the gob for use in numerical models of rock mass response to longwall mining. Photographs of actual mine gob were digitized to obtain approximate particle size gradations of gob material. The gradation curve was shifted down to a lab- oratory scale, and 20 uniaxial compression tests were conducted. Varying the maximum particle size was not found to affect the stress-strain behavior, but changing the gradation appeared to influence the stress-strain behavior. The stress-strain relationship of the simulated gob material was nonlinear, the stress-secant-modulus relationship, was approximately linear, and the stress-tangent-modulus relationship was approximately a second-order polynomial function. Equations were generated from these curves, providing numerical modelers with a means to estimate gob moduli based on the stress level. In addition, the experimental data were statistically evaluated using multiple regression analyses, producing a series of equations to predict the secant and tangent moduli from the given stress level, bulking factor, rock strength, and thickness-to-width shape ratio of the particles.

Jan 1, 1993

By Jacques Nantel

Mechanization has been at the core of productivity improvements since the industrial revolution. During the past 20 years, mining has derived spectacular progress from mechanization. In the future, however, mechanization alone will not be enough. In the next few decades, automation will bring about new generations of highly productive and safe machines, with low operating costs. Increased use of new and better technology is generally accepted as the prime factor capable of closing the productivity gap. The productivity gap is the difference between inflation and metal prices. The three S-curves in Fig. I represent the evolution of technology in general, and mining in particular. TI represents incremental changes. the dominant sort of technology changes in the mining industry: - Better drills, electric hydraulic drills vs. pneumatic drills, the drilling rate is twice as fast. - Better steel and bits, to accommodate the higher performance drills. - Improved chemical explosives. - Bigger trucks in open pits.

Jan 1, 1993

By M. K. Larson

The U.S. Bureau of Mines conducted a study to evaluate support interaction between conventional bolts and the rib at two Western coal mines. The principal goal was to develop guidelines for designing rib support under various conditions. At mine A, seven rib bolts were installed with load cells and monitored over a 4-month period. Fifty-seven pull tests were conducted with two types of anchors at various depths. At mine B, 163 pull tests were conducted. Results showed that during the 4 months of monitoring bolt load, tension in the bolts decreased over time in some situations and that anchorage capacity was reduced in a yielded zone. Load-versus-deformation plots from pull tests in the rib showed fundamental differences in anchorage behavior at the two mines, particularly when comparing results of tests in old pillars at mine A and tests in new ribs at mine B. Numerical modeling experiments indicate that coal bonding strength was the most significant factor in determining postyield anchorage capacity. Correlation of anchor yield point with anchor depth were more pronounced at mine A than at mine B; measuring torque may be a reasonable method of monitoring deteriorating anchorage capacity in a rib undergoing fracturing and yield.

Jan 1, 1996

Tracer gases are an effective method for assessment of mine ventilation systems, but their dispersion characteristics can differ substantially as ventilation parameters, such as flow path and velocity, vary. This research utilizes Computational Fluid Dynamics (CFD) to model a simplified full scale model mine, details a sensitivity study examining mesh size for an underground coal mine simulation, and examines gas dispersion parameters to determine the optimal model methods for simulation of tracer gases in underground coal mines. These models can be used to determine how a given tracer gas profile might be generated in a mine or areas of a mine that are not accessible, for example, immediately following a mine disaster. Accurate simulation scenarios can allow for the remote determination of the status of the ventilation network, but the sensitivity of the simulation at mine scale must be carefully examined.

Jan 1, 2012

Background information, formulae and a systematic set of procedures for estimating capital and operating costs for open pit mining equipment are presented in this paper. Firstly, equipment capital costs are required. These can be obtained from either suppliers, contractors or from first principles. The equipment is then divided into cost elements. Typically these are fuel and power requirements, spare parts consumption, wear items such as tyres, teeth and drill bits and finally repair and operating labour requirements. By consideration of the cost and life of each element a base cost can be derived. The base cost is then adjusted to suit specific site conditions such as the proximity to spare parts suppliers, the duty or ground conditions and the management and operator skills specific to the site. Hence, the same item of equipment can be costed to reflect different operations. Included are tables and data for typical plant items. Several examples are also given to illustrate the methodology being presented. The intention is to provide a set of procedures to allow costs to be built up from base level in a systematic and repeatable way. Applications for these costs include feasibility studies, budgetting and data for economic analyses.

Jan 1, 1990

By K L. Temel, W P. Player

The underlying message of this paper is that investment in prospecting, exploration and mining in New Zealand is welcomed. The Government's policy with respect to Crown owned minerals is for continuing investment in prospecting, exploration and mining which is in accordance with good exploration or mining practice. To encourage continued investment requires a business-friendly environment. Government policies and initiatives to enhance the business environment for the minerals and coal exploration and mining industries are discussed in this paper. As well, new initiatives under consideration, which have the purpose of enhancing the investment environment, are discussed.

Jan 1, 1997

The rapid advance in the adaptation of scientific knowledge to the treatment of ores, resulting in improved chemical and metallurgical processes, has enormously increased the possibility of working lodes profitably, which a few years ago were passed over as unpayable. By the discovery of chlorination, and later of "Cyanidation," by the highly improved methods of concentration, and by the rapid advance in our knowledge of smelting (for which we are greatly indebted to Americanmetallurgists), and by the gradual replacement of scientifing principles and enlightened management, for rule-of-thumb methods formerly in vogue, many large low grade bodies have been opened, and are now paying dividends, which were,twenty years ago, looked upon as hopelessly unpayable. It has been more especially in these large low grade ore bodies, that modern methods have been benefical; for small lodes must be rich to pay at all, as they cannot be worked on the same gigantic scale, but even in these a percentage of metal is saved which formerly was absolutely lost.To make these large deposits remunerative it is, however necessary to try and find the point of greatest economic advantage, to handle the ore in vast quantities, to erect huge plats to treat it, to substitute automatic appliances for hand labour as far as possible, and to combine several processes supplementary to one another, so that ore which is not amenable to one process, shall be saved, by another; and by doing...

Jan 1, 1901

By Gray Mullins

This paper presents experimental results from a study to assess the interface bond between a cast-in-place concrete seal slab and prestressed concrete piles in cofferdams. Three different seal slab placement conditions - fresh water, salt water and bentonite slurry - were evaluated and the results compared against controls where no fluid had to be displaced by the concrete. Normal pile surfaces were investigated. Additionally, the situation of ?soil caked? piles was also investigated. Both model and full-scale tests were conducted. In the model tests, twenty eight 15 cm square prestressed sections were used with the embedment depth varied between d-2d, where d is the width of the pile. In the full-scale tests, 16 specimens were tested. The prestressed piles were 36 cm square with the embedment varied between 0.5d-2d. Four of the sixteen piles were cast with embedded gages located at the top, middle and bottom of the interface region. The results showed that loads were transferred to the piles over an effective area, not the entire embedded depth. Significant bond stresses developed even for the worst placement condition. Recommendations are made for revising current values in specifications.

Jan 1, 2013

This field guide is designed for use in planning pollution control and reclamation activities on small sand and gravel operations. Its purpose is to assist operators in selecting environmentally desirable pollution control and reclamation procedures based upon their particular mining situation. The guide includes information on interpreting physical and cultural factors that must be considered in planning and implementing a mining and reclamation program, achieving environmental protection objectives, and improving community/industry cooperation. Included as appendices are a summary of state laws and a list of additional readings on the subject.

Jan 1, 1981

By R. A. D. Pattrick, R. A. F. Ixer

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. At Calliachar Burn, 14 steeply dipping quartz-sulphide veins, with and without gold, infill master joints that crosscut gently dipping metasediments and metabasics of the Pitlochry Schist Formation. The wallrock is extremely bleached and enriched in sericite, chlorite and carbonate. Gold grades vary from high with quartz-galena-pyrite to low with galena-chalcopyrite; the gold forms electrum inclusions smaller than 20 micrometres in pyrite or, rarely, arsenopyrite. At Urlar Burn, gold is present in small amounts in 4 quartz-galena-chalcopyrite veins. Although much of the mineralogy is similar to that at Calliachar, there are significant differences in Sb-, Te-, Bi- and Hg-bearing phases. Fluid inclusion data suggest mineralisation occurred over the range 320-140 degrees C, from fluids with significant CO2 and 2-13 wt% equiv. NaCl. Mantle-derived fluids appear to have been generated during the late Caledonian and focused by the Urlar Burn fault

Jun 19, 1905

OBJECTIVES ??REDUCE OPERATING COSTS ??INCREASE LIFE COMPONENTS ??EXTEND LIFE of THE DOZER ??REDUCE MAINTENANCE COST ??REDUCE DOWNTIME ??IMPROVE DURABILITY & RELIABILITY ??IMPROVE BOLD JOINTS PREFORMENCE ??IMPROVE SAFETY

May 1, 2004

By J. Jerome MacDonald, Stephen B. Flewelling

"In the base metals industry of today, operations required to continuously improve productivity and reduce unit production costs. Consistent with these goals is the improvement of the muck haulage cycle from open stopes with the No. 12 Mine.Existing haulage from open stopes occurs with LHD units experience at Brunswick indicates that LHD units have a higher unit cost per tonne mucked than loader-truck combinations when the haulage exceeds approximately 150 m.The reintroduction of open stoping at Brunswick made existing loader-truck combinations unsuitable. It was recognized that application of recent continuous loading technology could potentially result in significant unit cost savings and productivity increases.A review of the technology resulted in the testing of the Voest Alpine AL60 loader in the open stopes located on the 1000m Le vel. Testing began in January 1988 and finished in late November 1988. The test will provide experience as well as quantified production and maintenenace parameters f or the purpose of quantifying production unit costs and system productivity, ultimately resulting in a decision to further utilize or not utilize the loader as a primarymucking unit at Brunswick .INTRODUCTIONBrunswick Mining and Smelting Corporation Ltd. produces approximately 10500 tonnes per day from the No. 12Mine located 35 km southwest of Bathurst, New Brunswick Mining is the largest (single mine) producer of zinc in the world having mined over 52 million tonnes since 1964. Many years of production still remain with proven and probable reserves in excess of 90 million tonnes. Reserves grade at an average of 3.65% Pb. 8.99070 Zn, 99g/mt Ag and 0.32% Cu . The operation employs 1446 people with approximately 800underground including operations and maintenance staff.In the No. 12 Mine two major mining methods are presently utilized . The primary method is Mechanized Cut and Fill (MCF) accounting for approximately 6500 tonnes per day from four major areas. The remaining 4000 tonnes per day is produced from open stopes with the majority of 2800 tonnes per day being produced by the 1000 level.The 1000Level contains 30 million tonnes segmented into open stope blocks 30 m high, 15m and 30 m on strike , with a transverse width of 10m to 50 m (Fig. I). Stopes are organized on a primary secondary stope arrangement along strike. Primary stopes are undercut and overcut full size with the back fully cablebolted. All stope and lateral development is driven 4.0 m high. All stopes to date are flat bottom (Fig. 2). Primary stopes are filled with cemented rock- fill , secondaries with conventional rockfill, Haulage from the stopes is primarily with 8-yard LHD units ; mucking is approximately 50% conventional and 50% remote. Haul distance to date has averaged approximately 150m with current stope haul distances of approximately 300m. Haulage is presently to a small jaw crusher situated on the 1000 Level. From August 1989on, haulage will be to a set of ore passes feeding to a large gyratory crusher situated on the 1200 Level. Start up of the gyratory crusher corresponds to an increase in tonnage from 1000 Level to 4100 tonnes per day."

Jan 1, 1989