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By Timo Niitti

Within the minerals industry, flotation is the predominant method when processing sulphide ores. There is hardly any competition in this area because of the high efficiency and low costs of flotation. When processing other ore types magnetic or gravity• methods are commonly used and sometimes leaching methods are selected. The wide variation of the properties of gold (high value, low ore grades, softness, high specific gravity etc.) sets challenging requirements to the processing methods and particu­larly for flotation machines, which should be able to effectively recover free fine gold, coarse gold and gold bearing minerals throughout the full size range. In gold processes the amount of concentrate is usually low, but in some cases large amounts of gold bearing sulphides e.g pyrites has to be recovered. In gold processing seldom does only one method provide the optimum results, but the recovery is usually made using several complementary technologies: gravity separation, leaching and flotation are the most common ones. Mineralogy is the determin­ing factor when selecting the method or methods to be used.

Jan 1, 1995

By J. Harrison Daniel

Increasing concerns of industrial hygiene and worker health issues and resulting regulatory actions, coupled with continuing advances in mining systems, are placing new burdens on the industry and Federal Government; particularly, mine ventilation departments. More encompassing worker health programs are required to respond to Federal promulgation of regulations and to keep abreast of techno- logical advances in the mining industry. The relationship between the mining industry and Federal agencies involved in rulemaking is presented, along with the rationale of an Industrial Hygiene Management Plan. This plan or strategy focuses on developing partnerships and collaborative research groups to address the controversial health issues facing not only the mining workforce, but our society.

Jan 1, 1993

By J. N. Adamson

The Alcan Smelter project at Lynemouth on the Northumbrian coast draws cooling water for the power station through shafts and tunnels from the North Sea. The sea at this part of the coast is frequently very rough and even in calm weather the coastal currents are strong. The adjacent coal mine makes use of these currents to disperse colliery waste and discharges into the sea some thirty thousand tons each week. In consequence the sea bed is continuously shifting and the sea is black and turbid. Construction of sea shafts under these conditions presents difficulties as drilling from a floating vessel is hazardous and sea bed activity of divers is greatly hindered by the entire absence of visibility. After considering several alternatives a method of construction was agreed with the Consultants in which the drilling and also the lining of the shaft would be completed in sequence from an eight legged work barge (GEM 126). Each shaft would be drilled to full depth and a steel cylinder, with its ends closed temporarily, would be lowered into the hole and grouted into the formation to form a full-length permanent lining. The bell mouth for each shaft would be constructed in advance to form part of the cylindrical casing. On interception of the shaft by its appropriate tunnel the lower end of the cylindrical casing would be cut away and the internal walling of the shaft installed from below. After completion of construction the shafts and tunnels would be flooded and the bell mouth sealing covers removed by divers.

Jan 1, 1997

By W. W. Hartley

Following a Major underground coal mine incident there followed a review of the role of mines rescue ? the Queensland Mines Rescue Brigade. It wasn?t until 2002 that the real change started to happen. The issue of geographical distance was addressed by mines rescue sub stations being located on the mines sites with parent rescue stations in a central location. The funding was by means of a levy on the mining industry with legislative standards and performance included. The previous Rescue Brigades were not well organised (central districts) and the application of recognised quality management practices within local management was lacking. The structure was based on other nations models and miners managing miners was an issue for the organisation. The reform was some what painful and the QMRS organisation will still evolve with continuous improvement. Queensland has the National Champion mines rescue team for the eighth year. QMRS is participating at the level in the industry of influencing emergency systems and training senior mine management in ?Emergency Mine Management? coaching the industry in emergency response systems. We have come a long way. We have had some success and there is always the challenge of setting the standards, those we should aspire to and the courage to influence the industry to higher goals of a safer future.

Jan 1, 2010

By Rob Henson, Te-Lin Yau, Darryl Amick

The process industry faces tightening environmental regulations. In order to comply with these mandates, environmentally safe chemicals, such as oxygen and hydrogen perox­ide are becoming attractive oxidants. These oxidants appear benign but must be respected when involved in harsh environments. It is therefore important to address both the safety and suitability of materials selected for these environments. Otherwise, severe prob­lems, such as equipment failure or fire and explosion can occur. Laboratory and field experience will be used to discuss the perfor­mance of titanium, zirconium and Ti-45Nb alloy in piping systems for handling these environ­ments. Sealing methods for piping, pumps and valves of these metals will also be reviewed. For comparison, information on the performance of stainless alloys will be given.

Jan 1, 1993

By Keiichi Fujita, Katsumoto Ueda, Hiroshi Nakauchi, Naohiko Okumura

INTRODUCTION This paper presents (1) modified slipform system which was employed for simultaneous concrete placement for permanent lining and Instruction of a partition wall in the execution of a ventilation shaft 620m deep, and (2) current shaft sinking techniques which have been applicable and efficient for the subsurface conditions in Japan. MODIFIED SLIPFORM SYSTEM FOR PERMANENT LINING OF VERTICAL SHAFT General Information This paragraph deals with rapid construction by using modified slipform system for the permanent concrete lining and a partition wall of ventilation shaft, which has inside diameter of 620m and depth of 620m, of Enasan Highway Tunnel. The general feature of the shaft is illustrated in Fig. 1 and standard section of the shaft is illustrated in Fig. 2. The geological condition surrounding the shaft is mainly of ryolite and surface is of talus, but as a whole, they are rather weak and weathered rocks with faults, fissures and clay seams. 220mm borehole for the geological investigation was used as a drainage hole, predicting the amount of water inflow into the shaft to be 10t/min. The shaft was executed mainly by means of the conventional short step sinking method of 1.2m lift, employing temporary headframe and hoists. For each lift, 40 to 50cm thick temporary concrete lining was used. About 28,600m3 of rocks were excavated and

Jan 1, 1979

By James Wonneberg, William Edgerton

"Today’s underground construction megaprojects are tremendous feats of engineering on a massive scale, excavating through ground conditions once thought impossible, using new and innovative contracting practices. But one important truth remains unchanged; projects are built by people. What separates winning projects from the rest? Great people, working in great organizations. In straight-talk fashion this paper sets forth fundamental differences between good project leaders and bad ones, on topics ranging from client relations, design management, and scheduling, to use of the whiteboard, and everything in between. Broadly applicable to all corners of project delivery, this paper will resonate with project leaders from around the world and help identify skills necessary to succeed in the management of underground facilities. A NOTE FROM THE AUTHORS This is a training document, and not really a “paper” per se. We have attempted to tackle some big and potentially complex topics using bite-sized paragraphs, each of which are intended to promote thoughtful introspection and dialog. So please feel free to skip around, or even set this document down while you reflect on your own personal experiences, tactics, and philosophies. We have found that providing examples of “what not to do” is oftentimes more instructive than simply listing “what to do”, hence the Good/Bad format of this document. Please note that “PM” refers loosely to anyone on the project management team not just the “Project Manager”. We also wish to preface this with the following cautionary statements: • The authors do not pretend to be the “Good PM” in all cases. In fact, we’re almost certainly the “Bad PM” for some. We aim to improve on those areas. • It has been said that “The only real training for leadership is leadership.” (Antony Jay) We all started somewhere, and nobody has 20 years of experience on day one. • Converting this text into some sort of prescriptive checklist would be a disservice to the evolution of project management. Our world – and our awareness of it – is constantly changing. We must always be open minded to new ideas and different perspectives on project delivery."

Jan 1, 2016

By David D. Spencer

As in many other areas of the Mexican economy, the legal rules applicable to mining in Mexico have been changing fast. Mexico's mining sector is opening up to levels of international participation that were unforeseeable just a few years ago. Over the last several years, Mexico has made dramatic changes in its trade and investment policies. Many of these changes have their roots in the administrations of Miguel de la Madrid and perhaps even Jose Lopez Portillo. However, the current administration of President Carlos Salinas must be given credit for articulating, advancing, promulgating and implementing these changes. Just a few short years ago, few people believed Mexico would repeal so many of its restrictions on foreign investment and lower its average tariff level from something around 100% to less than 10%, where it is today. NAFTA and mining The North American Free Trade Agreement (NAFTA) is the most comprehensive international expression of Mexico's new policies. Except perhaps for the agreements establishing the European Union, NAFTA is the most detailed trade agreement ever written, consisting of about 2000 pages. The provisions of NAFTA with the greatest relevance to the mining industry include the chapters on investment and government procurement. Many mining companies may also find the temporary work provisions relevant. Finally, no discussion of NAFTA and the mining industry would be complete without some mention of the North American Agreement on Environmental Cooperation, the so-called Environmental Side Agreement.

Jan 1, 1994

By S. L. Bessinger

The need for improved safety and productivity brought about the introduction of longwall mining to the Appalachian coal fields. These same forces continue to drive developments in modern longwall equipment and mining practices. Current initiatives to improve productivity and safety are focused on automation and the effects of scale in equipment design. Longwall roof-supports, shearers and face-conveyors have changed significantly. Panel layouts have evolved to include larger total tonnages and provide for more rapid development of gate-entries. These advancements have improved longwall productivity and new production records are continually being set. Roof supports Reliability is implicit in the quest for automation. It is impossible to automate equipment if it is not reliable. To a large degree, this has been the problem with longwall shield automation efforts. The "electronic control" of shields depends on the proper functioning of electronic equipment, electrohydraulic valves and full-flow service valves onboard every support.

Jan 1, 1995

By W. T. Plummer

• The SuperBowl is a fluidized bed, semi-continuous, enhanced gravity separator for gravity gold recovery. The market for this type of equipment has, until recently, been dominated by a single supplier. Many mineral processors have encouraged the SuperBowl designers to develop competitive equipment for obvious reasons. • The primary beneficiary of competition in this field will be the mineral processing community because legitimate competition fosters continuous improvement in product and price.

Jan 1, 1996

By L. C. Morales

Mexico has an area of about 2 million km2 (772,260 sq miles), with volcanic activity, large shores and mountainous areas reaching as high as 6000 m (19,680 ft) above sea level. These conditions are favorable for most mineral deposits, some of commercial value and others as a source of mineral samples. In addition to its vast mineral wealth, Mexico has another valuable asset in its people. Even before the discovery of America, natives were successfully mining metals. During the colonial days, the mineral deposits were mined to increase the wealth of Spain. All this experience was passed from generation to generation. It created a tradition of mining and minerals processing engineers that currently accounts for about 182,000 people supported by mining-related activities. Nonmetallic minerals in Mexico have been mined by natives since the early days. They knew the value of kaolin clays for pottery, as evidenced by archeological findings. This experience was also passed from generation to generation and has become recognized worldwide as ceramic wares of high quality. The Talavera ceramic from Puebla is an example of family traditions many generations old.

Jan 1, 1994

By Karl J. Ellefsen

A geophysical investigation can provide valuable geologic information needed to characterize sand-and- gravel deposits and can be an attractive complement to more common characterization methods such as drilling. Although such investigations have been conducted already, a comparison of the different geophysical methods used in these investigations apparently has never been done. For this reason, a study was initiated by the Mineral Resources Program of the U.S. Geological Survey to determine the advantages and the limitations of different geophysical methods when used to evaluate alluvial sand-and-gravel deposits. The study is focused on those geophysical methods that are commonly available, because these are most likely to be used by industry. Furthermore, the study is focused on surface geophysical methods. Heretofore, four different methods have been evaluated. Three of the four methods-time-domain electro-magnetic (TEM) soundings, frequency-domain electro-magnetic profiling, DC-resistivity soundings-are similar in that they all measure the electrical resistivity of the ground with depth. Ground-penetrating radar, however, maps changes in the dielectric permittivity and for the electrical resistivity with depth. For all, four methods, the objective is to relate the measured physical quantity to the stratigraphy of the alluvial sediments.

Jan 1, 1999

By Steven W. Hunt, Jane A. Kettler, Barry R. Doyle

A sewer tunnel being constructed through an urban commercial area was to pass the site of a former gasoline service station. The site was known to have contained leaking underground storage tanks. An environmental assessment of soils on the alignment was performed, and measures were implemented to handle expected contaminants. Despite these precautions, an explosion occurred in the heading when liquid gasoline was encountered. Four workers were injured. This paper presents the findings of an investigation into the cause of the explosion, and examines how concerted efforts by the parties involved failed to prevent it. The level of guidance provided by OSHA Code provisions for tunneling in gassy conditions is discussed.

Jan 1, 1997

By Milton E. Wadsworth

The evolution of engineering education and research has been profoundly influenced by computer technology and has concomitantly followed changes in this technology. Today, virtually all faculty have access to at least two hierarchies of computers: desk personal computers and at least one echelon higher (workstations or a variety of mid-sized computers). Most faculty have access to three or even four hierarchies: the two listed, plus super-mini and super computers. The ready availability of computers at a low cost has increased dedicated and site-specific computer technology. This has permitted universities to move into the field of macro-engineering, to address increasingly complex problems in resource recovery, manufacturing and many other areas, including important societal problems, like the environment. The creation of university research centers indicates the growing importance of macro-engineering involving large systems of interactive components. Funding agencies have increasingly favored such centers since they cross disciplines, generate inter-university consortia and foster university-industry programs.

Jan 1, 1992

By J. L. Osiensky, R. E. Williams, J. Linehan

The hydrostratigraphy of uranium in situ leach sites consists typically of interbedded layers of sand, silt, clay and gravel deposited by fluvial processes. 'These layers usually form leaky multiple aquifer systems where sand and gravel aquifers are separated by silt or clay confining layers (aquitards). It is very important to evaluate the hydraulic properties of the ore zone aquifer and the confining layers by aquifer pump testing to ascertain the effects that in situ leach mining will have on the multiple aquifer system. The degree to which current methods of aquifer pump testing will provide the information necessary to adequately characterize the hydraulic properties of the ore zone aquifer and its confining layers is dependent upon the hydrostratigraphic conditions at the site and the limitations of the testing methods. The primary objectives of the aquifer testing program should be to evaluate the vertical hydraulic conductivity of the confining layers and to quantify leakage into or out of the ore zone under mining conditions.

Jan 1, 1984

By Remo Grandori, Fabrizio Antonini, Giorgio Dolcini

The paper describes the anticipated and the encountered geology, the TBM selection concepts and the machine special features, the tunnel sections, the achieved advance rates and the geological problems, the machine behaviour and the main setbacks caused by ground conditions the Authors also discuss the scopes for possible improvements to double telescopic shield machines, with special reference to their application under extreme geological conditions such as those that were met in the course of Los Rosales Tunnel excavation.

Jan 1, 1991

By Robert C. Schenk

The rapidly expanding, globally based mining industry provides many opportunities and challenges for the engineering construction business. This paper reviews some of the innovations that the industry is implementing to provide increased value in the design, construction, and successful start-up of new mine plant facilities. Approaches being taken to reduce installed-plant costs as well as related value-enhancement opportunities are discussed. Included are comments on new technology developments, use of automation and global communications networks, application of economic models as a project design tool, and management approaches being adopted to make the engineering construction process significantly more effective.

Jan 1, 1998

By Romeo Jurani, Ralph Dresel, Fred Kissell, Charles Parker

This report describes actions taken to control silica dust at the Yucca Mountain Exploratory Studies Facility (ESF), a tunnel located in Southern Nevada that is part of a scientific program to determine site suitability for a potential nuclear waste repository. The rock is a volcanic tuff containing significant percentages of both quartz and cristobalite. Water use for dust control was limited because of scientific test requirements. A major dust reduction was achieved with an intermediate air cleaning station located on a rear deck of the TBM trailing gear.

Jan 1, 1999

By Barry J. Hansen, Ruston A. Ford

Production of mine backfill from the tailings produced in a proposed Crandon concentrator is described. A process has been developed capable of producing suitable fill for the mining method selected for the Crandon orebody. It maximizes the placement of pyrite underground as fill and segregates tailings into pyrite and nonsulfide fractions. To determine the suitability and engineering characteristics of the backfill product for use underground, laboratory and physical stope simulation model testing was conducted. The results of the testing and the application of those results to the design of the backfill system ultimately affecting mine geometry and subsequent mine production will be presented.

Jan 1, 1981

By J. H. Heintz

This paper discusses the law as it relates to appraising operational mining properties in the context of a takings claim. Topics include the need for valuation expertise, the differences between de jure and de facto takings, an overview of the law of condemnation, including jurisdictional issues, and defining your strategic options according to the controlling statute. State condemnation law varies by jurisdiction and just compensation can be calculated by comparable sales unit-times-price, before ¬after-valuation, capitalization of income and discounted cash flow methods. Takings under Federal laws are reviewed, as is the necessity of assembling a team including attorneys, valuation experts including a mineral appraiser, a real estate appraiser, economists and geologists.

Jan 1, 2002