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By P E. H Gregg, D Horne, R B. Stewart, N Bolan

The Tui mine site is situated on the NW flank of Mt. Te Aroha, at approximately 400 m altitude. During underground mining operations two lead-copper-zinc ore bodies were exploited and processed on site. The legacy of the mining operation is a barren dam containing over 100 000 mm of sulphide-rich tailings. The Tui mine site is arguably the worst case of environmental degradation resulting from past mining activity inNew Zealand. Although the impacted area (approximately 4 ha) is extremely small by international standards, acid mine drainage (AMD) emanating from the abandoned tailings dam and mine adits has severely contaminated local streams and prevented natural plant recolonisation of the site for more than 20 years.   The suitability of the tailings as a potential plant growth medium was assessed with the end view of revegetating the tailings dam and alleviating AMD. This paper outlines characterisation work conducted on the tailings and summarises preliminary results from plant growth trials. The tailings contain up to 5% Fe, 1.15 % Pb, and 0.45% Cu in the form of sulphide minerals. The distribution of heavy metals, sulphate and total sulphur with depth indicates that the top 200 - 300 mm of the tailings have been extensively weathered since their deposition. The oxidation of sulphide minerals, particularly pyrite (FeS2 ) has reduced the pH of the tailings to nearly 2 in places. Below 300 mm the sulphide minerals are largely unweathered and the theoretical acid generating potential of the tailings exceeds 170 Mg CaCO3/1000 Mg tailings at certain depths. Plant growth trials were conducted to study the effects of lime and organic matter addition on the establishment of vegetation on the Tui mine tailings. Several plant species were assessed including some cultivars bred for their tolerance of heavy metals.

Jan 1, 1995

By Donald Thompson, Jessie Bonner, Ileana Tibuleac

Predicting ground motion from complicated mining explosions is important for mines developing blasting programs in regions where vibrations must be kept below certain levels. Additionally, predicting ground motion from explosions in complex 3D media is important for source size estimation for nuclear treaty monitoring. Both problems have been addressed under the development of a new series of programs including: 1) Generalized Fourier Methods to generate synthetic seismograms (Green’s functions) in 3D media for a moment tensor source implementation and 2) MineSeis3D, a program that simulates seismograms for delay-fired mining explosions with a linear relationship between signals from small size individual shots. To test the programs, three-component seismic recordings of three production shots at an iron mine in northern Minnesota were compared to synthetic waveforms in 3D media. Comparison of the observed and synthetic waveforms shows promising results. The shape and arrival times of the normalized synthetic and observed waveforms are similar for most of the stations. The synthetic and observed waveform amplitude fit is best for the vertical components in the mean 3D model but not as promising for the transversal components. The observed effect of spall on the waveform spectra was weak in the case of fragmentation delay-fired mining explosions. Commercial applications of the code could provide data needed for designing explosions that do not exceed ground vibration requirements posed by the United States Department of Interior, Office of Surface Mining.

Jan 1, 2005

By Robert Lee, Pertti Paavola

Automated vibration monitoring and web-based data distribution has proven itself on the largest single construction project ever undertaken in Finland. The excavation for the Kamppi Center Project in the center of Helsinki was completed in November of 2003 and involved the removal of over 200,000 m3 (260,000 yd3) of rock and over 1,700 individual blasts. A system was installed, incorporating 37 discrete monitoring points located throughout an underlying metro station, and other surrounding underground and surface facilities. After every blast, vibration data was automatically transferred from the monitoring network to a server database. Stakeholders were able to access and review vibration reports on a password-protected website within 90 seconds of each blast. This allowed engineers to verify that recorded levels were in compliance with established limits, before proceeding with subsequent blasts. The data was also imported into a semi-automated Scaled Distance tool for analysis using linear regression techniques. This was used to determine, and adjust for trends in blast-induced vibration.Copyright

Jan 1, 2004

By C. Wen

In Huoqiu region of Anhui Province, Fe2O3 occurs mainly in the form of specularite. Besides quartz, the gangue minerals include iron-bearing silicates such as chlorite and sericite which account for about 10% of the total gangue. The separation effect of conventional collectors is poor in the flotation of the minerals, that is, the average grade of iron concentrates is only 60-62%. Using the developed amphoteric collector can successfully realize not only the separation of specularite from various gangue minerals with results of iron concentrate grade above 65% and iron recovery of above 80% but also low temperature flotation at 15°C.

Jan 1, 2012

By W. E. Roscoe, H. Agnerian

The contour method can be used to estimate the mineral resources of a mineralized body. It relies on geological interpretation and allows the geologist to determine the plunge of a mineralized ore shoot along the dipping plane of the mineralized body. The technique is best applied to estimate tonnage and average grade of relatively planar bodies, i.e., where the two dimensions of the mineralized body are much greater than the third dimension, such as Archean lode gold vein deposits or mantos of massive sulphide mineralization, based on exploration drilling. For these types of deposits, the contour method can provide a clear view of the “mineralization landscape” with “peaks” and “valleys” along the plane of the mineralized vein. The technique also reduces the “nugget effect” of local high values commonly present in gold deposits. With sufficient drill hole information, the contour method may be used to estimate the tonnage and average grade of individual blocks within a mineral deposit. General procedures for the contour method are described in this paper, along with examples and explanatory notes.

Jan 1, 2002

By T Leach, B Fulton, R Stewart

Gold mineralisation at Porgera is inferred to have been derived from a deep differentiated magmatic source which is capped by a series of (now tilted) inward dipping sills and stocks, which comprise the Porgera Intrusive Complex. An arc normal transfer structure provides a conduit, at tile intersection with an arc parallel structure, into which basic magma derived from tile deep melting of mantle material has been emplaced. Two phases of mineralisation display an association with late stage feldspar porphyry intrusives. Stage I carbonate-base metal-style gold mineralisation occurs as early quartz-sericite, then massive sulphide and late zoned Mn-Fe-Mg-Ca carbonate vein/breccias. Magmatic fluids derived from the deep magma source, are interpreted to have migrated along me margin of a feeder stock to the sills, and south to Waruwari. Stage II epithermal Au-Ag quartz-style gold mineralisation occurs as early fluidised breccias and carbonate veining, followed by zoned quartz-roscoelite-carbonate-gold vein/breccias, and late carbonate and/or sulphate open space infill. Magmatic fluids are interpreted to have utilised the same plumbing system as the late stage feldspar porphyry intrusive, and then migrated into the Roamane Fault which was dilated by; dextral rotation on elements of the transfer structure, normal faulting, and refraction around the competent footwall hornblende diorite. Bonanza gold is localised in a jog in the Roamane Fault, hangingwall splits and at intersections with cross structures. Bulk low grade Stage I gold has been deposited by the mixing of magmatic fluids with cool gas condensate waters, whereas high grade Stage II gold mineralisation resulted from the rapid quenching of mineralised magmatic fluids by oxygenated groundwaters.

Jan 1, 1995

By Alonso Marchena, William Martínez, Joel Otero

En Arequipa, Moquegua y Tacna se han definido diversos arcos magmáticos. En los arcos jurásico, paleoceno y oligo-mioceno ocurren pórfidos de distintas características, los cuales presentan diferencias litogeoquímicas (LaN/YbN>20, Sr/Y>40, Eu/Eu*>1, U/Th>0.27, NbN/TaN>0.7). Estos parámetros pueden ser utilizados como guías de exploración, ya que son anomalías desde el punto de vista litogeoquímico. En caso no haya mineralización visible (depósitos ocultos), el empleo de estos trazadores en unidades ígneas (diques, cuerpos subvolcánicos e intrusivos) puede señalar la probabilidad de encontrar depósitos en profundidad.

May 22, 2019

By Oliver Bowles

"Simple systematic accounting that adequately records all transactions has long been regarded as essential to the welfare of any business enterprise. Some of the defects that detract from the prosperity of the slate industry are attributable to a lack of effectiveness in cost keeping. This condition has prompted the United States Bureau of Mines to make a detailed study of accounting methods for the slate industry, and to present for consideration a system of accounts, which it is believed would enable the industry to attain more economical management and operation if accepted by a fair proportion of its important units.The method of accounting presented herein has been worked out with the assistance of leading slate producers and the recommendation are tentative and are submitted in this form as a means of developing constructive criticism. Believing that cooperative effort in this, as in many other problems, will bring the most enduring benefits to the industry as a whole, the writer urges that the most earnest consideration be given to this vital problem now facing the slate industry.Grateful acknowledgment is made of the helpful assistance rendered by R. E. Eckert of the accounting firm of Eckert, Degan, and Palmer of Easton, Pa., in compiling the charts and the explanatory text. He has brought to this work a wide knowledge of accountancy, supplemented by a background of direct contact with the slate industry, and his presence at the various conferences has been of great advantage in clearing up difficulties. The National Slate Association sponsored the cost study and chiefly through the efforts of President W. H. Smith and Secretary W. S. Hays, has aided greatly in conducting it. Acknowledgment is also made of assistance rendered by William F. Marsh of the United States Bureau of Mines."

Nov 1, 1929

By P R. Denize, V S. Wein

A brief review of the Waipipi Iron Sands Limited company history and operations over the past ten years is made along with a summary of the benefits of this mining company to New Zealand. Land rehabilitation procedures in coastal dune lands are described in detail and brief mention is made of a study of animal health and copper uptake. The paper concludes with a summary of the increased emphasis on agronomy and restoration as the mining operation commences dredging in a better class of grazing land.

Jan 1, 1981

By L. A. Cramer

Platinum metal was first utilized by the Inca civilization in South America where it was found in alluvial deposits along the San Juan and Atrato rivers that lie between the Andean mountain range in Colombia and the Pacific Ocean. The nuggets found in these rivers average between 77% and 86%platinum, 7%?8% iron and small amounts of copper, gold and other Platinum Group Metals (PGMs). The Incas often alloyed platinum with copper to increase its workability and fabricated various ornaments from it.

Jan 1, 2001

Copper, zinc, lead, and silver in the discordant magmatic-hydrothermal orebody of the Conrad Mine, N.S.W., all have a relatively high mean abundance. Any single concordant sulphide orebody containing the same metals has a similar order of mean abundance of only one or two of these, particularly copper, copper and zinc, or zinc and lead.The relative abundances of the metals in the Conrad orebody vary more widely than in concordant orebodies, and the lead-zinc-silver and copper-zinc-lead relationships are significantly different.INTRODUCTIONIn previous investigations of metal abundances in sulphide ores, the basis of selection of the orebodies was their form, and to some extent their geological setting, rather than hypotheses concerning their origin. In all cases they were generally concordant with the bedding of the sedimentary or meta-sedimentary rocks enclosing them, and most occurred in volcanic-sedimentary sequences. Their mineralogies were simple, and they were copper, copper-zinc, zinc or lead-zinc rich in composition. Most were of the type ascribed by several authors to exhalative-sedimentary processes.In one of these investigations (Stanton, 1958), it was pointed out that since the metals in ores of this type showed similar abundance patterns and behaviour, it would clearly be of interest to examine, and to compare with them, orthomagmatic and vein types, unquestionably derived from their igneous rock associates.The present investigation is concerned with a single orebody, of clearly discordant type, and of indisputable hydrothermal origin. The abundance and behaviour of copper, zinc, lead, and silver have been determined and compared to similar data fOl!' the concordant type. Such a comparison tests the possibility that metal abundance patterns of base metal ores may be indicative of the mode of ore deposition.

Jan 1, 1963

On the more important mines it is almost essential to have a general plan of the surface. A special feature of this plan should be the indication thereon of a suitable arrangement of contour lines, either wholly over the surface of the property or at parts where may seem most useful. The importance of having these contours marked on the plan will be best appreciated by the engineer, in selecting the best available site for a proposed new plant, in locating a tramway, in connecting the surface with the underground workings to the best advantage, or in solving many similar problems that come within his province. The closer the contours are together vertically the better, the limitation being the trouble and expense of getting them on to the plan. They may range from five to fifty feet apart but a distance of ten feet will be found, in most cases, to be the most useful.In deciding the datum level from which these contours are to be measured, it is best to depart from the ordinary sea level datum, and use instead the highest available point on the property. This datum will be called zero and all levels will be reckoned so many feet below it; thus by a contour marked 160 on the plan, it will be understood that the level of the plane of the contour is 160 feet below the highest available point on the property. This system of measuring levels downward is readily suggested from measuring the depths of shafts from the brace or of excavations from the original surface.

By W. A. Heitbrink, J. D. Ashley, R. E. Gresh, J. A. Organiscak, A. B. Cecala

Many different types of mobile equipment used in surface coal mining utilize enclosed cabs to protect equipment operators. The overburden removal process is extremely dusty and can cause excessive exposure to respirable dust, especially crystalline silica. After equipment is used for years, many components of the enclosure deteriorate and its effectiveness is greatly reduced. This report discusses a cooperative research study performed on an Ingersoll Rand DM45E surface drill, retrofitted with a new Sigma pressurization and filtration system. Respirable dust concentrations were substantially reduced from 0.64 mg/m3 during pre-testing to 0.05 mg/m3 during post-testing with the new system, representing a 92% reduction in dust levels in the drill cab. This new system appears to be a very well-built and sturdy device, well-suited for the mining industry.

Jan 1, 2002

By Fawad S. Niazi

Ever since the use of the cone penetration test (CPT) in geotechnical practice, attempts have been made to correlate CPT parameters with pile capacity components of unit end bearing (qb) and unit shaft resistance (fp), thus deriving multiple CPT-based pile design methods. These methods focus on "capacity" only without consideration to complete axial pile load-displacement (Q-w) response. Estimated capacities from these methods also exhibit considerable scatter without any consensus on their consistency. In addition, load-displacement curves obtained from axial load tests on highly expensive and extensively instrumented piles can exhibit different shapes. Nevertheless, a single value from the curve so obtained dictates the design capacity. Currently, there are at least 42 different criteria defining capacity with considerable variation in the values obtained thereof. The Randolph elastic solution, which provides a framework for analytical evaluation of pile load-displacement response, requires the profiles of soil stiffness. The fundamental soil stiffness defined by the small-strain shear modulus (Gmax) can be obtained from shear wave velocity (Vs) readings via seismic piezocone tests (SCPTu). The secant stiffness (G), which softens from Gmax corresponding to operational load levels, can be obtained by generating stiffness reduction curves from back analysis of load tests. Then, using appropriate G values, the Q-w curve can be defined for conditions similar to the database from the pseudo strain (w/d). Thus, a complete framework for optimal integration of SCPTu data, Randolph elastic solution and back-analysis of field operational stiffness can be established for complete axial pile foundation analysis.

Jan 1, 2011

By BUREAU OF MINES

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its prin- cipal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctua- tions, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War II has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic informa- tion and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that produc- tion rates and reserves have a proportionate relationship.

Jul 1, 1964

By R. E. Ray

Compared to conventional fully ducted axial and centrifugal fan systems, jet fans can offer a number of advantages for control of smoke during fire emergencies and dilution of diesel engine exhaust products in vehicular and rail tunnels. The success of jet fan applications is the result of a balance between the temperature de-rating of the fan, buoyancy forces and the installation momentum transfer efficiency. This paper provides a case study of a unique application of vertically-mounted jet fans in ventilation shafts used to provide both emergency ventilation and pollution control for an overbuild created by the construction of a series of commercial high-rise residential buildings over a portion of an existing passenger rail line. A detailed evaluation of a set of shafts for one building is presented, including a discussion of the calculation methods used to estimate the required jet fan capacity and the results of the subsequent numerical analysis using Computational Fluid Dynamics to simulate the performance of the jet fans during train car fire emergencies.

Jan 1, 2009

Development of New Comminution Testing Methodologies for Geometallurgical Mapping of Ore Hardness and Throughput The emerging discipline of 'geometallurgy' is becoming increasingly recognised as a discrete and high-value activity that reflects an ongoing trend towards more effective mine site integration and optimisation. Constrained sampling that reflects and defines inherent ore body variability is a key geometallurgical requirement. This requires use of larger numbers of low-cost physical testing which can be applied to small sample volumes suitable for defining natural variability. The AMIRA P843 'GeMIII' project (Geometallurgical Mapping and Mine Modelling) is a major industry-supported research initiative designed to develop new tools, methods and protocols to support geometallurgical integration. As part of this integrated research a new more rapid low-cost comminution test (GeM Comminution index) has been developed which can be employed as a front line tool for geometallurgical mapping purposes and predictive throughput modelling. The test has been designed to be inserted into routine assay sample preparation and is based on constrained jaw crushing protocols linked to analysis of resultant size distributions. Extensive validation and modelling has shown the GeM Comminution Index (Ci) is correlated with the Drop Weight index A*b and Bond Mill Work Index (BMWi). Large scale trials have been conducted within a commercial assay laboratory to demonstrate and optimise incorporation of the Ci test into routine sample preparation protocols. While Ci based estimates of A*b and BMWi are not as precise compared to larger volume more expensive test-work, the ability to undertake large numbers of tests typically in a systematic down-hole manner, provides a high level of data support through adjacency. A Ci based approach is highly suitable for variability mapping, domaining and selecting large composite samples for more precise testing. Within the context of the AMIRA P843 project this forms part of an integrated work flow designed to support geometallurgical integration. The development of a comminution test linked to routine assay sample preparation represents significant value adding to a process that in most cases is already going to be carried out. This paper introduces the Ci test concept and application to geometallurgical testing for throughput modelling

Sep 13, 2010

By Lamont G

The significance of blasthole stemming in determining blasting efficiency has been extensively studied for small diameter holes using gelignite explosives. Recent developments in blasting technology with the use of large diameter holes and low cost blasting agents have not included studies of the effectiveness of different types of stemming materials. A review of previous measurement techniques and the relevance of these earlier results to present stemming practice is presented in this paper. A survey of operating mines in Australia provided information for this analysis. The value of stemming in reducing blast noise and improving blasting efficiency is generally accepted but the use of bulk-loaded explosives in underground operations has resulted in the practice of eliminating the use of stemming material.In surface operations drill cuttings are used for stemming on the basis of availability rather than efficiency in providing resistance to movement. The development of laboratory testing techniques, based on noise level and borehole pressure measurements, to evaluate the relative efficiency of different types of stemming materials is described. The results of an extensive series of tests with ANFO explosive showed similar trends tothose obtained from earlier published results with gelignite type explosives. Conclusive quantitative results on the relative effectiveness of different stemming materials will require minor modifications to the existingequipment. Observations and the results of pressure measurements indicated the presence of shock wave effects which caused the ejection of the top section of the stemming column when using coarsely fragmented material.

Jan 1, 1979

By Z. W. Nkosi, M. Sephton, J. H. Potgieter

The exhaust system is a complex assembly of various components performing important tasks in harsh environments. Carbon steels have been used extensively in exhaust systems, but pressure for lower cost, increased fuel efficiency; lower hazardous emissions, weight savings and increased life expectancy have shifted the emphasis to stainless steels. In response to the growing consumption of stainless steels in automotive exhaust systems, the need to properly evaluate their corrosion resistance properties in order to ensure their appropriate use, has increased substantially. This paper evaluated the most common corrosion and oxidation tests developed that are used and applied it to four common stainless steels often employed in hot end exhaust components. In a summary considering the weight loss of an alloy, it general corrosion rate and pitting resistance under all the test conditions for hot end exhaust components, results indicate that 434 was by far the most corrosion resistant alloy, followed by 1.4509 and 321, and lastly 304 was the least corrosion resistant. In general, the ferritic stainless steels, especially 434, outperformed the austenitic ones under all the test conditions.

Jan 1, 2006

By L. C. Stilwell

Input-output analysis is a major branch of quantitative economics, and is used to analyse the flow of goods and services between production sectors in a national economy. Its purpose is to determine the relative value-adding capacity of each sector. The model has also, in recent years, found increasing use in assessing the environmental and ecological impact of development projects. It has, however, never been applied to individual production facilities, such as large mines, which themselves have complex economic structures, through which there is a flow of goods and services. Conventional cost and accounting systems, as used on mines, treat production sectors as separate cost centres, and do not determine the inter-relationships between them. This can lead to incorrect conclusions on the relative value of sectors and their impact on the total economic performance of the facility. This paper explains the basic principles of input-output analysis, and presents an example of its application to a simplistic model of a mine, which is used in the absence of any real data. The paper concludes that, by forcing definition of the value adding function of each sector, input output analysis will facilitate control of inputs, or costs. This will result in optimal application of resources and exploitation of ore reserves. The authors realise the model needs to be tested on an operating mine, and hope this paper will result in an opportunity to do so. The authors wish to thank the anonymous referees for their valuable comments.

Jan 1, 2000