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Analyses of scheelite from all the known scheelite fields in the South Island of New Zealand have shown that the scheelites are essentially molybdenum-free. The scheelites are almost stoichiometric CaWO4, except for some strontium replacing the calcium, with a maximum of 0·92 per cent SrO. Variation in strontium content appears to be' related to the metamorphic grade of the enclosing rocks.

Jan 1, 1970

By R A. Lynch

The state-of-the-art in cave seismic monitoring is reviewed, with the latest developments in active seismic monitoring included. Seismic monitoring systems are routinely used by most of the world’s block and panel caving mines to track the cave initiation and progression. The current best practice is to use the cloud of seismic event locations as a proxy for cave growth somewhere below. Problems with event location reliability due to seismic ray bending around the (unknown) cave are side-stepped by using sensors installed above the cave. However, the aseismic gap – the (unknown) distance between actual cave back and seismic event cloud – currently hinders reliable estimation of cave geometry.Velocity inversions using the passive seismic data are inexpensive and should be undertaken more routinely. The straight-ray methods should be used with caution, as the underlying assumptions are invalid in caving environments. The double-difference method is more correct for the caving situation, and there have been some promising results published. Constrained geometric inversions make a lot of sense, but have yet to be demonstrated successfully.Two active seismic source have recently been developed for use in the caving environment: a piezoelectric source for ranges up to a few hundred metres and a pneumatically-powered source for ranges up to a kilometre. These sources produce signals on standard mine seismic sensors that can be used to measure seismic velocity variations down to 0.01 per cent resolution. This allows the cave progression to be monitored by measuring tiny changes to seismic velocities as the rock above the cave is fractured and destressed.CITATION:Lynch, R A, 2016. Active and passive seismic monitoring of cave front evolution, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 217–224 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Jan C. Still

The Haines-Klukwan-Porcupine subarea of the Juneau Mining District (JMD) is located in the northern portion of the JMD and consists of the land between the Alaska-British Columbia boundary, the Chilkoot Valley, Glacier Bay National Park boundary, and extending south to the Davidson Glacier and the Chilkat Peninsula and Islands (fig A-I). This area was studied as part of the larger JMD study in a cooperative effort between the Alaska Division of Geological and Geophysical Surveys (ADGGS) and the Bureau during 1985 to 1988. Prior to this, during 1984, the ADGGS and the Bureau cooperated in a study of the Porcupine mining area and during 1981 to 1983 conducted separate studies in the area. Field work was conducted by foot, boat, truck, and helicopter. Figure A-I shows the Haines-Klukwan-Porcupine sub-area and shows the areas covered by previous Bureau and ADGGS studies. PHYSIOGRAPHY AND CLIMATE The physiography of the subarea ranges from gentle to rugged. Glaciers formed the major features in the sub-area and left "U" shaped steep walled valleys and rugged mountains. The Chilkat, Chilkoot, Klehini, Tsirku, and Takhin are the major rivers in the subarea. The higher mountains are glacier clad and some valleys still harbor glaciers that reach the valley floors. Lush forests and dense brush predominate up to timberline at about the 2,000-foot elevation. Low point in the subarea is at sea level in the area around Haines while the high point is 7,434 feet at: Mount Henry Clay in the Porcupine mining area.

Jan 1, 2012

By R. G. B. Pickering

The hard rock gold and platinum mines in South Africa have seen little development in the technology of mining. Holes are still drilled in the rock?though the latest water hydraulic rockdrills will complete that task in two minutes compared with the eight hours for hand drilling. Charging up is with far safer explosives and with available initiation systems it is no longer necessary to run up the face lighting each fuse. Movement of rock in the stope is predominately by means of scraper buckets and scraper winches?these were first introduced in the 1920s. Support is still mainly rock, either in situ pillars or backfill, or alternatively wood. Just as the mining process has changed very little it is hardly surprising that the productivity of mining is also relatively unchanged. Major efforts have been made to mechanize the mining process. However, most of the narrow reef mines where ?trackless mechanized mining? was introduced in the early1980s have reverted to conventional mining. In the wider reefs mechanized mining is the option of choice, unfortunately most of the gold and platinum mines have very narrow reefs that are not suitable to ?off the shelf? equipment. The move to introduce room-and-pillar mining into the narrow UG2 reefs is at the expense of mining more waste with the reef, fortunately it appears that appropriate waste and reef separation processes are available. Room-and-pillar mining followed by long hole drilling and blasting of a narrow slot of reef out of the pillars currently appears to offer the best of both worlds?maximum reef recovery with minimum waste dilution.

Jan 1, 2002

By Tristan Worsey, Nathan Rouse, Kyle Hall

Drilling accuracy is the foundation to any successful blast operation. Even the best blasting practices cannot overcome poor drilling and still obtain desired results. Inaccuracies in boreholes can result in flyrock, increased vibration, uneven floor, and other undesired effects. As depth increases, variation in actual burden and spacing is expected even if collars are located precisely. Problems arise when this deviation reaches a point where it adversely affects the function of the blast design. Not only can unsafe conditions such as insufficient burden at the face develop, but poor fragmentation can compound adverse effects. As with any troubleshooting, problems cannot truly be fixed if they cannot be measured. As a result, significant work has been done in the past on this subject. Currently, there are both cheap and expensive methods used to quantify deviation for a given borehole. However, implementation of these techniques is limited. In general production blasts, little is known about the variance in designed versus true borehole geometry. This is especially true if the blaster does not see telltale signs of drilling deviation. However, losses in blast performance may exist and provide an opportunity to obtain better fragmentation and reduce fines. As drill and blast operations strive for better optimization, greater focus is being placed on drilling accuracy and solutions to this problem. The following paper details the use of several current methods for deviation measurement in order to help prevent compromises of safety and improve overall blast performance.

Jan 1, 2018

By James R. Wickens, David La Rosa, Robert E. McIvor, Adrian Dance

"The comminution circuit at Barrick Cortez Gold Mine uses an open circuit primary jaw crusher followed by a standard SABC grinding circuit. The grinding circuit incorporates a 26’Ø x 11’ SAG mill, an Omnicone 1560 pebble crusher and a 16’Ø x 28½’ ball mill. Both mills are driven by 4500 HP motors.In 2007, several comminution circuit studies were performed to assess circuit performance and map a course for improvement. This paper discusses the results of those studies including an analysis of mine-to-mill opportunities, grinding work index efficiency, and ball mill functional performance. Subsequently, improvements to the circuit were made to enhance operating efficiency. Specifically, improvements to the pebble crusher liner configuration, advanced process control system (expert system) and ball mill classification and ball charge are discussed. In addition, other current and future improvement opportunities are discussed.INTRODUCTIONThe Barrick Cortez property is expanding to include the new Cortez Hills open pit and underground mines. Ore from these new mines will be processed in the existing Pipeline mill facility. In conjunction with ore characterization work, performance of the comminution circuit needed to be quantified. Thus, in 2007, the comminution circuit was surveyed and opportunities for improvement identified.Figure 1 below shows the Pipeline mill flowsheet. It is a standard SABC grinding circuit using an open circuit primary jaw crusher followed by a 26’Ø x 11’ (7.92m Ø x 3.35m) SAG mill, in closed circuit with a Omnicone 1,560 pebble crusher, and a 16’Ø x 28½’ (4.88m Ø x 8.69m) ball mill. Both mills are driven by 4,500 HP (3,357 kW) motors. The SAG discharge screen aperture is 5/16” (8 mm) x 1-1/16” (27 mm) slots. Ball mill circuit classification is done with Krebs D20B cyclones."

Jan 1, 2009

By Bruce Conard

For many years, Bruce Conard has been engaged in reading about and discussing the desired sustainability of the mining and metals resource industry. He has, however, become concerned that there is a greater issue that requires our urgent attention: what challenges do we face as a global society? His Distinguished Lecturer presentation traces the idea of environmentally sustainable economic development but concludes that a business’ interest in its sustainability is predicated on the sustainability of our global society. Conard reviews some of the most serious challenges, including population growth, clean energy supplies, freshwater availability and climate change, and calls on scientists and engineers not only to apply their skills in helping solve these challenges, but most urgently, to speak with intelligence and passion about the need to act now.

Jan 1, 2014

Numerical models play a significant role in the design of safe underground mining excavations and support systems. Advances in the capabilities of numerical modeling software, together with ever increasing computational speeds, have made it possible to investigate the very nature of the large-scale rock mass and its response to mining excavations. The improved understanding of the rock response obtained from modeling enhances our designs, resulting in greater stability and safety of the mining excavations. To help advance the state of the art in this field, the National Institute for Occupational Safety and Health organized the International Workshop on Numerical Modeling for Underground Mine Excavation Design. The workshop was held in Asheville, NC, on June 28, 2009, in association with the 43rd U.S. Rock Mechanics Symposium. The proceedings include 10 papers from leading rock mechanics and numerical modeling experts in the United States, Canada, Australia, and Germany. The papers address a wide range of issues, including various numerical modeling approaches, rock mass modeling, and applications in coal and metal mines.

Jun 1, 2009

By Steven Putt

Seismic While Drilling (SWD) is a newly developed technology in the mining industry. Improving upon Measurement While Drilling (MWD) systems, SWD measures mechanical properties of the rock at incremental depths down a blast hole at a much higher resolution. SWD is also immune to common failures and inconsistencies of MWD such as operator and drill specific variation. Seismic While Drilling records the velocity and elastic modulus of the rock with centimeter accuracy in real-time. These properties measured while drilling blastholes are then used as a proxy for density which can be used for: • High resolution geologic modeling • 3D ore control • Drill and blast optimization • Drill to mill tracking One of the distinct challenges with SWD systems is the sheer volume of information acquired. With thousands of measurements per blasthole, the data can be overwhelming for even an experienced engineer. To overcome this complex challenge, the latest cloud computing and analytics models have been simplifying and organizing the data. These newer technologies can amplify an engineer’s capability by delivering actionable insights into their drilling and blasting workflows. The paper presents new results from Datacloud during recent Seismic While Drilling trials in iron ore, metallurgical coal, and hard rock mines around the world. The measurements are compared with wireline geophysical logs, core data, drill cuttings, and conventional measurement while drilling (MWD) systems to validate the technology and show how the data can be used.

By Sigurd L. Lamhauge, Karl Gunnar Holter, Svein E. Kristiansen

An innovative sprayable waterproofing membrane in combination with the traditional Nordic method of waterproofing with polyethylene foam sheets was used for the waterproofing of the tunnel. The sprayable membrane was integrated in the final sprayed concrete lining in a sandwich structure, hence constituting a composite water-proof lining based on sprayed concrete. The spray able membrane was applied in areas with small to moderate water ingresses, making up approximately 50% of the total area requiring waterproofing in the tunnel. State-of-the-art application technology with a computerized spraying robot was used. A consistent application of the required thickness at a high speed was thereby achieved.

Jan 1, 2007

Mr. Chairman, distinguished guests, ladies and gentlemen. Thank you for asking me to your conference, with its most fundamental and appropriate topic of 'Investment in Mining'. I must confess at the outset that I am one of those Australians who has rarely visited your fair land of New Zealand. This is in fact only my third visit, with all three related to Institute Conferences, and all much too brief. In so many ways your country provides a counterpoise to ours, despite the obvious disparities in size and population. And I am not only referring to the Bledisloe Cup! We would certainly each be much more lonely without the other, in this strange long-lost corner of the globe û if globes can have corners. Such an important factor in common in our shared heritages has been the mineral industry we have won from our alluvials and our rocks û especially for gold. So much of the major mineral developments which have supplied the world's appetite for metals and fuels in the past two hundred years has come from the countries settled in that period by people from Europe, especially those from the British Isles. So much of the technology for mineral and metal extraction has come from the skills of those people in New Zealand and Australia. And so much of the further development of metal processing and manufacturing of productive equipment has come from those people and from their cousins throughout the world. It is, I believe, a fair question to ask why we have failed to build on those early and considerable successes, and why we have in so many ways apparently been so content to allow others to add value to our raw materials, and to take our technological developments on to levels far beyond those that our domestic markets could sustain.

Jan 1, 1988

global mining boom and in-creased demand for iron ore has lead to a resurgence in the mining industry in Minnesota. At the combined 81st Annual Minnesota Section of SME Meeting and 69th Annual University of Minnesota Mining Symposium, April 15-16 in Duluth, MN, this resurgence was the hot topic as new mining projects were featured in the keynote session. The meeting attracted more than 400 mining industry professionals, including engineers, executives, mining managers and suppliers from around the world. This year?s theme was ?New Ventures in Mining.? The meeting included concurrent technical papers sessions, a keynote session that featured three distinguished speakers and a panel discussion that provided updates on new mining developments in the state. The Minnesota Section of SME technical papers were presented in concurrent sessions, one on mining and one on mineral processing. The mining session included papers on drilling, ore blending, slope stabilization, dust control and operations management. The mineral processing session included papers on plant-control technology, ball mills, pellet strength and fans. Also offered was an SME short course titled ?Simulation based pellet induration optimization.? The Minnesota Section of SME held its annual business meeting during the conference. The 69th Annual University of Minnesota Mining Symposium technical sessions were held on April 15 and also consisted of concurrent sessions on mining and mineral processing. Mining session topics included logistics management, real-time performance measurement, uses for taconite aggregate and environmental issues. The mineral processing session included papers on ore liberation characteristics, zeta potential studies, induration modeling, fuel optimization and conveyor belts. The combined conference included a tradeshow with more than 80 booth spaces featuring vendors offering products and services to Minnesota?s booming mining industry. More than 900 people, including conference registrants and special invited guests of the vendors, at-tended the tradeshow opening reception. This was the largest trade show in many years ? an indication of the vitality of the mining industry in Minnesota.

Jan 1, 2008

About MAC ? The national organization of the Canadian mining industry ? Mining, smelting and refining of base and precious metals ? Mining of iron ore, diamonds, uranium, oil sands, coal and industrial minerals ? Many associate members ? www.mining.ca

Aug 1, 2013

By Jury P. Nazarov

"At present the traditional study of crystal lattices of nmerials in a topic “flota tion mineralogy ” is used up. The present investigation is development of the a sclsical approaches to t he analy sis of ideal crystal lattices and f ormation on the basic obtained results of consultation, having practical chara cter.The strategy of develop ment floatation reagents i s offered, which basic pr inciple – complementary assembling m olecules forming surface co mpounds so thatth e steric charact eristic of the “visitor "" (of a polar gro up of molecule SAS) corresponded to the st er ic requirements of the ""o wner"" (elementary cell of a mineral), or coincided inter molecular cavities). In itsh case process of for mation of surface com pounds ca n be considered(a first approximation) as a realization of a principle of the design er "" LEGO "".The approach, which basic idea consi deration actioonf reactant ions and ions of ele mentary cell as three-di mensional objects is developed. And at suchp paroach the laws of a ster eometry - laws describin g spatial effect s are applicable. Thus it is possible toconsider a miner al surface as a mat r ix - basis for formation of the requirem ents to polar group of a molleec cuollector, and or (it is possible) depressant. As a whole approach represents a generalized principle double com plementation, enveloping both power, and geometric asp ects (concept ""lock "" and “key "" - spatial conform ity. Figure 7 (left). Fragment of a crystal lat tice of ap atite. Oleic acid ions interact on ly with th e calcium cations locate d on a long axi s of an elementary c ell. Magenta colour represe nts the calciu m cations, which are n ot particip atin g in interactio n, as th e degree of screening by ions neighbours exceeds 1.Figure 2. (right)The illustration of space complementary. “Afterbuilding” an elementary cell of apatite (radical PO4) related molecules of the visitor – alkyl phosphate (polar group PO4). Cations of calcium are not shown."

Jan 1, 2003

By J. Goyman, K. R. Rawling

"1.1 Location and Transportation ServicesNanisivik Mines Ltd. is located at latitude 73°, 3,200 km north of Montreal and 700 km north of the Arctic circle, on the south side of Strathcona Sound, which is an arm of Admiralty Inlet, in Northern Baffin Island. The orebody and mill site are 4 km distant from Strathcona Sound which provides deep water anchorage for ocean transportation of concentrate to Europe during the short northern shipping season from mid-July to mid-October.The operations and the resident community have direct jet aircraft service from Montreal two days per week, and local nights connect with other Arctic communities in the northern Baffin region. Bulk supplies and general cargo are delivered in the summer shipping season.1.2 HistoryThe Texas Gulf Sulphur Company, now Kidd Creek Mines Limited, staked claims in the Nanisivik area in 1957 and carried out exploration through to 1968. After the Kidd Creek orebody was found, Texas Gulf optioned the property in 1972 to Mineral Resources International Inc. (MRI), which undertook further exploration and completed a feasibility study.Nanisivik Mines Ltd. was formed in 1975, with MRI as the majority shareholder and minority shareholdings held by Metallgesellschaft, Billiton and Texas Gulf. Strathcona Mineral Services Limited was retained to manage the project during both the construction and operational phases."

Jan 1, 1984

By Thomas M. Barczak

State-of-the-art longwall roof supports provide effective strata control, but failures of these support systems still occur. To identify failure mechanisms and the impact these failures have on the safety of the support system, the U.S. Bureau of Mines has been conducting research on shield mechanics in the Bureau's unique mine roof simulator, as well as field studies of in situ support loading and investigations of longwall failures, Three types of failures are discussed: (1) inadequate support capacity, (2) structural failure, and (3) instability. Hypothetical situations with proposed courses of action and case studies of actual longwall failures are described. This information is intended to assist the Mine Safety and Health Administration (MSEIA) and industry mining personnel in safety evaluations of longwall roof support systems.

Jan 1, 1989

By D. Harrington

A uniform hoisting-signal code for mines hoisting from more than one level, if adopted by all mining States, would be beneficial to employees and owners alike and should largely reduce the number of hoisting accidents. Misunderstood hoisting signals cause many shaft accidents involving injuries to men, damage to equipment, and loss of production from the resultant delay. Many of the metal-mining States have adopted codes for hoisting that are effective within the borders of that State but usually entirely different from the signal code, if any, in use in an adjoining State. For many years safety engineers have recognized this lack of uniformity as a distinct hazard, but a uniform code has never been adopted by the States or by the mining industry in those States that have not incorporated signal codes in their mining laws or mining regulations.

Jan 1, 1944

By E. Sun

Tailings disposal is a significant consideration for the mining industry, with the majority of the ore processed in most mining operations ending up as tailings. Several tailings dam failure accidents have occurred during the past few years and mine tailings dam failures are occurring at relatively high rates. Tailings dam failure is disastrous with the serious damage and the loss of lives. To increase the tailings dam safety, a tailings dam monitoring and pre-alarm system (TDMPAS) based on the internet of things and cloud computing platform has been accomplished with the abilities of real-time monitoring of the saturated line, impounded water level, rain fall and the dam deformations etc. The TDMPAS has been applied in several mines in China and helped the mine engineers monitor the tailings dam safety and get warning information automatically and remotely in any kind of weather conditions. This work has been demonstrated the tailings dam monitoring and pre-alarm system (TDMPAS) is meaningful to monitor the tailings dam physical safety condition. The TDMPAS could be applied to monitor all the national tailings dams online in the future.

Jan 1, 2012

By S. E. Phillipson

The Mine Safety and Health Administration?s (MSHA) Roof Control Division (RCD) collects a variety of geological and engineering information pertaining to mining conditions in surface and underground mines throughout the United States. Recently, lineament analyses, trends of geologic structures, and inferred stress directions based on mapping at mines with problematic ground conditions, have been integrated into a GIS. The incorporation of different kinds of information into the same geographic coordinates and map projection, placed on digital geologic maps, allows site specific data to be evaluated in a regional geospatial context, identifying trends in the orientation of horizontal stress or patterns of structural geologic features. As more information is collected, the GIS will evolve as a tool for district- and basin-wide evaluations of controls on ground instability, and may evolve into a predictive tool for some kinds of geologic hazards. In addition to the geologic and geotechnical evaluations, the GIS also serves as a searchable database of previous mine investigations. The database can be searched for a variety of criteria, and the results displayed in real geographic coordinates to find the locations of previously visited mines or to evaluate mine fatality and injury data. This not only allows old reports to be found, but also places the information in a geospatial context with respect to neighboring mines or geographic areas. The GIS also has the capability to serve as a digital mine map repository, where maps can be stored in digital, georeferenced format for display in relation to each other and various themes of interest. This allows evaluation of multiple seam mining interactions and proximity to other mines, and on a national level could serve as an abandoned mine map database.

Jan 1, 2008

By E. Nickel

"Bi- and multilateral banks as well as export credit agencies in the OECD countries, but also numerous commercial banks, last year committed themselves to compliance with the World Bank’s standards. These environmental and social guidelines, also known as the Safeguard Policies, are the strictest international standards in the area of financing of major investment projects. The Safeguard Policies are procedural and quality guidelines by means of which socially and environmentally relevant impacts can be taken into account in the planning and implementation phase of a project. Objectives of the Bank Safeguard Policies are to ensure that environmental and social issues are evaluated in decision-making, to reduce and manage risk of projects and programs, and to provide a mechanism for consultation and disclosure of information. They are often referred to as the "10+1 Safeguard Policies," since ten of the guidelines address environmentally and socially relevant issues, while one guideline is exclusively concerned with public participation ("Public Disclosure"). In the presentation, the transparency of risk management measures and emergency response plans in pipeline projects will be discussed as an indicator of sustainability. The discussion is to be carried out on the basis of the results of an evaluation of several major pipeline projects, which have been financed at least in part by multilateral banks over the past few years. The controversies surrounding some of these projects due environmentally and socially relevant impairments connected with the investments have also been addressed by the Extractive Industry Report of the World Bank. Pipeline construction was the investment type chosen for the examination to be presented here, since pipelines frequently start in remote, unspoiled regions, and their routes often cross various natural zones and areas with various social structures. The question of safety during construction and operation of the line is always central to these projects; not only for the responsible authorities but also for other societal groups involved, such as environmental associations."

Jan 1, 2005