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By Roger Best

In the mining industry, where some of the vehicles are larger than a one-story house, tire maintenance cannot be accomplished by the tire shop alone. It takes an army of people to maintain a fleet of 100 trucks that may be transporting gold, iron ore, oil sand, copper or coal from an openpit to a refinery and eventually delivering the product to a customer. Everyone working in and around these mammoth machines has a duty to help with the maintenance of the tires, whether they know it or not. These responsibilities comprise observation and reporting hazards up to and including changing out a tire and recording the information in a tire-tracking program such as TreadStat.

Jan 2, 2010

By Charles Dumaresq

The management of mine tailings poses a complex range of potential risks, including physical risks, such as the risk of catastrophic failure of a tailings facility and chemical risks such as the risk of long-term leaching of contaminants into the downstream environment. If these risks materialize, they can lead to a wide range of impacts on people and the environment, including human fatalities and severe impacts on downstream ecosystems, and the costs of recovery borne by industry, communities, governments, and society as a whole can be immense. Tailings facility failures in Canada (2014), Brazil (2015 and 2019), South Africa (2022), and in other locations around the world underscore how high the stakes are when mines produce and manage tailings (WISE Uranium Project 2019). Understandably, many people do not trust the mining industry to manage tailings responsibly. As an industry, it is our responsibility to manage tailings in a manner that is responsible and strives to minimize harm associated with tailings management, including effectively managing both the physical and chemical risks associated with tailings. Standards have an important role to play in responsible tailings management by setting expectations for standards of care and providing a means to measure and report on performance. In jurisdictions with strong legal requirements for tailings management, standards play a complementary role, pushing performance improvements in areas that may be difficult or impossible to address in legal requirements. In jurisdictions where legal requirements are lagging, standards may represent the de facto leading practice and may be the primary tool to help ensure responsible tailings management. Implementation of standards can help companies demonstrate that tailings are being responsibly managed and help build trust and credibility. Most importantly though, standards are important tools to help ensure that the risks associated with tailings are reduced, and that remaining risks are effectively managed. However, we must recognize that conformance with standards can have a down-side – the proverbial two-edged sword. Having standards is vital but there is a risk that implementing standards becomes a “box checking” exercise, with ongoing conformance leading to complacency. We must not allow ourselves to fall into the trap of believing that, just because we are complying with applicable standards and laws, we are therefore doing our best, and that “it can’t happen to us.” In addition, if conformance becomes the goal and the standard does not have mechanisms to drive continual improvement, then once the standard is met, there may be no incentive to improve. The point of complying with standards is not to pass the test. The point is to manage tailings responsibly, prevent catastrophic failures, and minimize harm. The point is to do better, because we must do better. To do that, we need to strive not for conformance, but for excellence in tailings management, driven by continual improvement and a quest to do better.

Feb 1, 2025

By Beverly Cramp

In 1995, mining engineer Alain Gachet thought about using Earth-observation satellite imagery to search for precious minerals. The latest radar Earth-observation satellite, Canada’s RADARSAT-1, had just been successfully launched at the time, creating new opportunities for commercial applications. Gachet was working in Congo Brazzaville as an oil executive and general secretary of Elf Congo for the French national oil company Elf Aquitaine. He understood that the RADARSAT-1 launch promised new and cost-effective sources of data for mineral and oil exploration. “It was early 1996 before I ordered my firstRADARSAT-1 satellite images,” said Gachet. “I was first struck by the quantity of information delivered by the radar images. Linear structures and faults were clearly defined and subtle topographic features were tremendously enhanced,” he said. “It was ‘tree top geology,’ but this kind of information appeared to be key for finding new gold seams.”

Jan 1, 2003

By John J. Murray, Michael T. McRae, Michael A. Krulc, Kathy L. Schuler

The San Vicente Pipeline Tunnel Project involves the construction of an 8.5-foot-diameter water pipeline in an 11 mile tunnel in San Diego, California. The tunnel is located in extremely variable geologic conditions of strong granitic and volcanic rocks, weak sedimentary rocks, abrasive conglomerates, and mixed face conditions. One reach of the tunnel is a 5,200-foot mixed face reach that includes Friars Formation Conglomerate overlying granitic rock. Due to the variable ground conditions in this reach, the use of a TBM was deemed too risky and the contract documents required drill-and-blast and hand mining methods. Although it was not required, the contractor elected to construct this reach using NATM methods. This paper describes the geology of the 5,200-foot mixed-face reach, the design evaluation, and the construction challenges faced on this project.

Jan 1, 2007

Minerals are fundamental to the U.S. economy, contributing to the real gross domestic product (GDP) at several levels?mining, processing and manufacturing finished products. The estimated growth rate for the real GDP of the United States was 2.1 percent and the nominal GDP was about $13.8 trillion in 2007 (Table 1). The prime interest rate decreased to 7.25 percent in December from 8.25 percent at the beginning of 2007, reflecting actions taken by the Federal Reserve Board to counter financial difficulties surrounding subprime mort-gages. Delinquencies on subprime mortgages increased throughout the year, affecting not only the delinquent home owners but also financial instruments invested in mortgage-backed securities. The average contract mortgage rate for the purchase of previously occupied homes in the United States was 6.35 percent in November; a slight decrease from 6.37 percent in January but still greater than 5.34 percent reported in July 2003, the lowest rate in the past five years. With the tightening of credit, the seasonally adjusted annualized rate for new privately owned housing starts declined 27 percent from December 2006 to November 2007. The loss in the residential market was balanced by a 9-percent increase in nonresidential construction between January and August 2007, during which slight increases occurred in nearly all

Jan 1, 2008

By C. D. Litton

Laboratory experiments were conducted to determine the responses of a prototype smoke detector and a commercially available photoelectric smoke detector to smoke particles generated from various combustion sources. The prototype smoke detector combines optical scattering measurements with ionization chamber measurements in order to reduce/eliminate nuisance alarms due to the presence of airborne dusts or diesel exhaust particles. The commercially available smoke detector is designed for use in harsh environments where airborne dust represents a major problem due both to nuisance alarms and detector contamination. In the experiments, the responses of the two detectors were measured when exposed to smoke particles from the exhaust of a diesel engine and from a variety of fire sources, including wood, coal, styrene butadiene rubber, and No. 2 diesel fuel. For the solid fuels, data were obtained for both smoldering and flaming combustion. This report describes the experiments, their results, and the use of these results as they apply to early-warning fire sensors capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by either airborne dust or the products produced from diesel engines. Subsequent to these laboratory experiments, six smoke detectors were installed in an underground limestone mine for further testing and evaluation. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By John M. Dale

Now that the price of sulfur has reached unexpected high levels, it is little wonder that sulfur from surface ores is again receiving attention. In most instances, it is advantageous for an ore to be at or near the surface. However, it is a distinct disadvantage for sulfur ore to be close to the surface because it precludes the use of the Frasch process. The Frasch process depends on the presence of at least 180 m of uniform overburden to allow pressure injection of superheated water into the sulfur-bearing formation to melt the sulfur. In the Frasch process, sulfur separates cleanly from the gangue underground and comes to the surface in a very pure form. Surface sulfur deposits, particularly those in the Western Hemisphere, exist largely due to volcanic activity, and sulfur separation from the gangue is a formidable technical problem. None of the surface deposits are large compared to some of the Frasch deposits, but at the present sulfur price, they are certainly of economic importance. From the turn of the century until 1975, the price of sulfur was for the most part $18-$28/t. However, with the price of sulfur now over $154/t, there are a variety of technical alternatives to consider for sulfur surface ore separation that may not have been economically attractive a few years ago.

Jan 9, 1981

By Steve Skelhorn, Dan Ifrim

"A tunnel project poses many challenges; the operation of the Tunnel Boring Machine (TBM) being one of them. Mechanized tunneling is known as a safe and effective alternative to other methods in terms of schedule and cost; however, efficiency can be severely affected by a bad TBM selection and qualification and employment of inexperienced operators. The success of a mechanized tunneling project involves a comprehensive and interdisciplinary consideration of all contributing factors such as TBM technical specification and selection, TBM design and procurement including ancillary equipment and tunnel linings. The tunnel equipment selection along with the operation can make or break the project. The objective of this paper is to address the importance of the skills and qualifications of the TBM crew with particularity to the TBM Operator. The study includes the Owner and Consultant involvement in the selection and pre-qualification of the TBM crew and specifically the TBM operator as well as the role of Contractor and TBM manufacturer in TBM operator training. This paper also analyzes the possibility of issuing a TBM operator certification, and discusses the benefits and significance of periodic training and certification programs. INTRODUCTION Training in the tunneling industry is not a new topic. The industry continues to evolve and become more complex with technology advances and expansion of mechanical tunnelling to mechanized shaft construction, large diameter drilling and mining industry applications. The need for professionals trained to operate mechanized tunnelling equipment is ever increasing, while there is a significant number of veterans who will be ageing out in the next 5 years. Consequently attracting young professional is a very important aspect of sustaining a qualified pool of professionals. For any given tunnel project, the owner and the engineer spend up to several years, studying the ground conditions during preliminary and final design. Post contract award the contractor spend additional months studying the ground again to develop the optimum means and methods for construction. All this time and money spent at the beginning of the project has the purpose of developing the optimum tunnel design, assessing the risk associated and implementing mitigation measures to reduce risks to acceptable levels. Following the tunnel design process, sophisticated TBMs are being specified and sourced to ensure the best tool for the job. The question raises here: Are there available experienced/trained professionals capable of operating these sophisticated machines?"

Jan 1, 2016

By Steve Kral

For a state whose roots are in mining, most Colorado residents probably do not realize that the industry still contributes heavily to the state’s economy. In 2005, the industry contributed, directly and indirectly, about $8 billion to the state’s economy, according to the Colorado Mining Association (CMA). It employed nearly 10,000 people at mines and support businesses. And the mining industry in Colorado is one of the highest paying occupations in the state, averaging about $80,000 a year in wages and benefits. The state’s coal mining industry produced nearly 36 Mt (40 million st) of coal in 2005, valued at $800 million, the CMA said. That was seventh in the nation. And Colorado’s only major gold mine produced 10.2 t (329,000 oz) last year, valued at $124 million. That was third in the nation. And Phelps Dodge’s Henderson Mine produced about 12.7 kt (28 million lbs) of molybdenum, valued at $350 million. Colorado is the largest molybdenum producing state in the nation.

Jan 1, 2006

By Mark A. Jirsa

The Biwabik Iron Formation is a ~1.9 billion year-old sequence of iron-rich sedimentary rocks that was metamorphosed at its eastern- most extent by ~1.1 billion year-old intrusions of the Duluth Complex. The metamorphic recrystallization of iron-formation locally produced iron-rich amphiboles and other fibrous iron-silicate minerals. The presence of these minerals in iron-formation along the eastern part of what is known as the Mesabi Iron Range, and their potential liberation by iron mining has raised environmental health concerns. We describe here the geologic setting and mineralogic composition of the Biwabik Iron Formation in and adjacent to the contact metamorphic aureole of the Duluth Complex. The effects of metamorphism are most pronounced within a few kilometers of the contact, and decrease progressively away from it. The contact aureole has been divided into four metamorphic zones?each characterized by the composition and crystal structure of the metamorphic minerals it contains. The recrystallization of iron-formation to iron-rich amphibole minerals (grunerite and cummingtonite) and iron-pyroxene minerals (hedenbergite and ferrohypersthene) is best developed in zones that are most proximal to the Duluth Complex contact. ©2007 Elsevier Inc. All rights reserved. Keywords: Iron-formation; Mining; Fibrous; Mineralogy; Metamorphism.

Jan 1, 2007

By Geoffrey Fosbrook, Donald Phillips, Anil Parikh

The Second Avenue Subway is a $16.8 billion project planned by the Metropolitan Transportation Authority (MTA) in New York City. It will reduce overcrowding and delays on the Lexington Avenue Line, improving travel for both city and suburban commuters, and improving access to mass transit for residents of the East Side of Manhattan. The project is a new, two-track, 13.5 km (8.5 mile) subway extending from Lexington Avenue at 125th Street in Harlem on the north end of Manhattan, to Water Street at Hanover Square in Lower Manhattan. The first phase of construction includes rock tunnels from 92nd Street to 62nd Street and connection to the existing 63rd Street station, three new stations, and track and systems from 105th Street to 63rd Street, allowing service between 96th Street and Brooklyn via an existing Broadway Line. The following describes the Project in detail, discusses the construction challenges addressed in the design, and the initial design/build contract to be awarded in 2005. A discussion of the planned mined construction of two rock caverns and a cut-and-cover station construction are also included.

Jan 1, 2005

By Christy Z. Lueders

Introduction More and more women engineers are joining the traditionally male mining industry. Are they successful? Do they encounter special problems? How do men in mining respond? How can the mining industry effectively use its female resources? What contributes to the success of a woman in mining? What can male engineers do to ease the entry of female professionals into the workforce? An STM survey conducted last spring provided some answers to these questions. All BS graduates in mining, mineral engineering, and extractive metallurgy from 1960-1979 were surveyed. Nearly 60% of the female graduates, from 17 universities, completed questionnaires. The women were asked why they chose mining, how they relate to predominantly male co-workers, what job skills they have gained, and what areas of work they most enjoy. They were also asked how problems of a two-career family are solved. Data were gathered on salaries, titles, specialties, and products handled. Respondents, assured of confidentiality, are identified only by title. Many male mining executives were also questioned for their advice to women in mining. Profile of the Survey Participant The "typical" female mining engineer works with coal, is employed by an operating company, feels she works very hard to prove her abilities, does not want to be treated as an anomaly, and someday wants to be an independent consultant. Of the respondents, 44% listed coal as the most familiar product, 12% said copper, and the rest listed products from industrial chemicals to oil. Titles varied widely but women managers are rarely found. However, the majority of the survey population graduated after 1976 and thus lacks substantial experience. Of 102 female graduates, only 25 graduated before 1977. Since then, there has been a steady increase. The American Association of Engineering Societies reported that in 1980 more than 100 degrees were awarded to women in minerals engineering. Education Highly Valued Twenty-two percent of the women surveyed had graduate degrees, 38% planned further education, and 12% listed a PhD as their goal. The majority of graduate degrees are in technical fields. There were only two MBAs. Five women intended to pursue law degrees, and one woman, with a mining engineering degree and an MBA, is a part-time law student. Along with advanced education, the women agree that production experience is needed for career advancement. However, only 28% of the women have worked in production. Many women, especially younger grads, commented that these are the toughest jobs to get. This is a universal complaint, from males as well as females, though women seem to encounter more opposition. Several women mentioned they were small or slight of build and managers tended to shy away from hiring them for production jobs. Two-Career Marriages The most difficult problem for two-career couples is relocation. Whose career takes priority? Fifty percent of the women said transfers or offers would be examined on a case-by-case basis, weighing pros and cons for both parties. The husband's career took priority with 47% of the women; their own careers, with 3%. These statistics conflict with comments from two employee relations managers. Both said most female engineers they've encountered are married to men who follow their wives' careers. Seventy per cent of the married respondents said their husbands were also engineers. Four said their husbands were engineers at the same company. Some male and female engineers met on the job; others joined the company as a "package deal." Both partners being engineers can ease relocation problems, since an area or company offering one spouse a job can often provide a spot for the other. A company may benefit by getting two new hires for the relocation costs of one. Most companies contacted have policies that allow married couples to work at the same division, but discouraged them from working in the same department. With 40% of today's marriages ending in divorce, one risk is that one or both parties may quit. One personnel executive said there were several couples, each spouse in a different discipline, who were work¬ing out very well at his division. However, he recognized the potential for problems if, for instance, one gets promoted and the other doesn't, or salary increases are unequal. The personnel executive said he has actively recruited married couples, and would again, were each person competent.

Jan 10, 1981

By D. R. Shoemaker, H. W. Judges

A 16.5-kt/d underground molybdenum mine is being developed at Questa in northern New Mexico by Molycorp Inc., a wholly-owned subsidiary of Union Oil Company of California. The new $200-million underground project will revitalize mining and milling activity at Questa, where small scale underground mining first began in 1920. Large scale open-pit mining was initiated in 1965 but now, because of the high stripping ratio, surface mining is being phased out. Construction of the underground mine began in 1979, and first produc¬tion is scheduled for early 1983. The company expects full capacity-9 Gg of molybdenum per year-to be reached in 1984.

Jan 6, 1980

By R. N. Powell

The Pipeline ore body was discovered in March 1991. The construction of the new mine and mill did not start until early March of 1996. Upon completion of permitting and corporate project approval, the 289 million USD project was “fast tracked”. The commissioning began 11 months after start of construction and the project ended 40 million USD under the budget figure. The objective of this paper is to review and highlight the Pipeline Project history from discovery, design, lawsuits, permitting, and re-design through to current - 1998operating practices. Particular emphasis will review the process design, design mistakes, and design successes. The paper will review project history, feasibility, design concepts, operator training, construction, financial and the current operation. Additional discussion will review what design features worked and which did not work within the process plant.

Jan 1, 1999

By J. M. Mutmansky, A. Wang

This paper defines the elements of a basic economic model for decision-making when considering a methane drainage system for an underground coal mine. A drainage system will require significant capital and operating expenses; hence the decision to utilize drainage must be made carefully. The model outlines the basic structure of decision-making and considers the costs and benefits when the methane is marketed and when the methane is vented to the atmosphere. The effects on mine safety and the dust levels in the mine are also considered, both in a general format and as economic variables. Sources of information for executing this decision-making are provided for an actual mine decision.

Feb 24, 1997

By M. R. Shahan, W. R. Reed, S. Klima, T. W. Beck

"Testing was conducted to determine the ability of foam to maintain roof coverage in a simulated longwall mining environment. Approximately 27% of the respirable coal mine dust can be attributed to longwall shield movement. Developing controls for this dust source has been difficult. The application of foam is a possible dust control method for this source. Laboratory testing of two foam agents was conducted to determine their ability of foam to adhere to a simulated longwall face roof surface. Two different foam generation methods were used; compressed air (CA) and blower air (BA). Using a new imaging technology, image processing and analysis utilizing ImageJ software produced quantifiable results of foam roof coverage. For CA foam in 3.3 m/s (3.3 m/s (650 fpm)) ventilation at 3 minutes after application, 98% of agent A was intact, while 95% of agent B was intact on the roof. At 30 minutes after application 94% of agent A was intact while only 20% of agent B remained. For BA in 3.3 m/s (3.3 m/s (650 fpm)) ventilation, the results were dependent upon nozzle type. Three different nozzles were tested. At 30 minutes after application 74-92% of foam agent A remained, while 3-50% of foam agent B remained. CA foam seems to remain intact for longer durations and is easier to apply than BA foam. However, more water drained from the foam when using CA foam which demonstrates that BA foam retains more water at the roof surface. Agent A seemed to be the better performer as far as roof application is concerned. This testing demonstrates that roof application of foam is feasible and is able withstand a typical face ventilation velocity, establishing this technique’s potential for longwall shield dust control. INTRODUCTION NIOSH personnel have visited many longwall operations at various geographical locations in the U.S., conducting benchmark surveys to characterize current operating practices and dust control measures in use. Sources of respirable dust generated from the longwall face have been identified as: intake (10%), stage loader (20%), shields (27%), and shearer (43%) [1]. Dust generated from the shearer, armored face conveyor, and the stage loader can mainly be controlled by water sprays and increases in ventilation air quantities, however, research has demonstrated limited effective controls for dusts generated by shield movements [2]. One possible approach to mitigating shield dust generation is to apply a layer of water or foam to the shield-roof interface. Once this interface is blanketed with foam or water, dust will be less likely to become airborne and contaminate the airways over the personnel walkways. Though water is an abundant and common dust control measure, roof applications have limited success because water is unable to remain in-place in adequate quantities for the necessary duration between application and shield advance. Past and current testing of foam for material properties has shown that it has longer applicability times, ranging from 10 to 60 minutes [3] and has shown better performance for dust control, ranging from 19-96% improved efficiency over water [4, 5, 6, 7, 8]. The majority of this foam dust control research has focused on dust control efficiency at the longwall shearer or continuous miner cutting drum."

Jan 1, 2017

By Gerald C. Smith

Introduction Newmont Mining Corp.'s Carlin Gold Mining Co. mines gold ore and waste material from four open-pit mines in Northeastern Nevada. Combined production rate is 24.5 Mt/a (27 million stpy). The company is producing gold bullion from the 2.4 kt/d (2600 stpd) Carlin Mill No. 1. and the 2.3 kt/d (2600 stpd) Maggie Creek heap leaching plant. In August 1985, the 6.3 kt/d (7000 stpd) Carlin Mill No. 2 at Gold Quarry came on-line. The total combined throughput of 11.2 kt/d (12,000 stpd) will make Carlin Gold Mining one of the largest US gold producers. Feasibility studies are underway to increase the total gold out-put from Gold Quarry. This will be done by adding a continuous dump-leaching process that will recover gold from lower grade ore. History In 1961, Newmont exploration geologists located claims in the Lynn Creek mining district near Carlin, NV. An exploration drilling program revealed significant gold mineralization. A stepped-up drilling program revealed an ore body with an estimated 10 Mt (11 million st) of ore containing 109 t (3.5 million oz) of gold. Test results in 1963 allowed metallurgists to develop the flowsheet and design for a 1.8-kt/d (2000-stpd) countercurrent decantation (CCD) cyanide plant. Carlin Gold Mining Co. was formed to operate the property. Carlin purchased its first mining equipment in 1965. This consisted of two Bucyrus-Erie 2.7 m3 (3.5 cu yd) shovels and nine 27.2 t (30 st) Wabco Haulpak trucks, two Inger¬soll-Rand track-mounted drills, one Chicago Pneumatic T-650 rotary drill, one rubber tired Michigan 280 dozer, one Caterpillar D-8 36A track dozer, one Caterpillar 16 motor grader, and the necessary ancillary equipment. The fleet was capable of mining 3.2 Mt/a (3.5 mil¬lion stpy) working two eight-hour shifts, five days a week. In 1967, one P&H 1500 3.8 m3(5 cu yd) diesel electrical shovel and three 59 t (65 st) Dart trucks were added to the fleet, along with a Chicago Pneumatic rubber tire mounted rotary drill. This equipment addition increased the mining capabilities to 5.7 Mt/a (6.3 million stpy). Three separate pits, the Main, East, and West, within a 1.6-km (1-mile) radius of the Carlin mill were being mined. The crew consisted of 46 hourly men and three supervisors. This equals 497 t/ total hourly manshift (548 st) or 407 t/total manshift (515 st). Rising gold prices in the early 1970s allowed lower grade deposits to be mined at greater distances from the mill. The Boot-strap pit, 19.3 km (12 miles) north of Carlin, was started in 1973. Two Hough 45.4 t (50 st) front-end loaders, four Wabco Haulpak 45.4 t (50 st) trucks, and a second track type D-8H dozer were added. The higher grade ore was trucked to the Carlin mill using three

Jan 11, 1985

By B. Salopek, D. Rajkovic, D. Rumenjak

In decision making support system, that are used in various fields of environmental protection (environmental impact assessment, environmental management systems, setting environmental standards and regulation, etc.), it is often important to apply various mathematical environmental engineering models. The question of linking environmetal engineering modeling to decision making support system used in environmental protection is not yet methodically solved. The reasons for that could be manifold. Decison making support systems, used in environmental protection, because they are simply taken from bussines decision making, are not often adequate for specific problems raised in environmental protection. On the other hand, there are great number of types of models in environmental engineering, what urges the problem of finding the way of their proper linking with decision making support systems. The application of fuzzy logic in that field is estimated as one of possible solution of the problem.

Jan 1, 2005

By R. Owen, T. Canty, C. Marks

The industrial vision system provides on-line 2D particle size analysis for aggregate slurries in both the overflow and underflow of hydrocyclones. This paper covers required vision system features allowing CCD cameras to function in the harsh environment of a mine milling area. The study conducted demonstrates the system’s capacity to obtain particle size distributions for controlling hydrocyclonic separators. The particle size distribution is obtained within seconds and immediately updated to allow for process adjustments. Results are then provided as a graphical computer generated display or output as a 4-20mA current loop for process control. The primary use of the vision system is in classifying particles in cyclone overflows which are often a few microns in size. Typical size information for actual mine slurry samples are presented and possible control schemes discussed.

Jan 1, 2002

By E. F. Schnitzer, S. R. Mamoyac, P. J. Wampler

During 1996 and 1997, Oregon experienced flooding on a scale not seen in many years. Some gravel pits located near rivers experienced erosion and, in several cases, breaches between the gravel pit and the river. Initial evaluation of several sites that experienced breaches indicates that impacts to the river system are complex and vary significantly from site to site. The impacts to the adjacent river system may be viewed as both positive and negative. Several floodplain-mining sites in Oregon located in areas of historic river flow have reverted to active riverbed. In many cases, state and federal fisheries biologists and university researchers see the resulting increase in channel complexity and habitat as favorable. The Oregon Department of Geology and Mineral Industries – Mined Land Reclamation Program (DOGAMI-MLR) is performing additional studies of the impacts to the off-channel areas that resulted from the 1996 floods. More data is needed to make sound floodplain decisions regarding mining.

Jan 1, 1999