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By Inoka E. Perera, Robert Hildebrandt, Gerrit V. R. Goodman, Krzysztof Cybulski, Zdzisław Dyduch, Michael J. Sapko, Marcia L. Harris

To prevent coal dust explosion propagations, rock dust needs to be lifted and suspended in the air with the coal dust during an explosion. The addition of anti-caking agents prevents caking of rock dust in the presence of water. Mining and rock dusting processes can frequently create alternating layers of rock dust and float coal dust on mine surfaces. For this test series, a thin layer of coal dust was distributed on top of a layer of either treated or non-treated rock dust in the Experimental Mine Barbara, Poland. The experimental results compare the effectiveness of treated and non-treated rock dusts to attenuate a propagating coal dust explosion initiated with either strong or weak methane explosions. Experimental results indicate that the treated rock dust performs better than non-treated rock dust in arresting a propagating explosion, especially in the presence of moisture.

Jan 20, 2020

By Kenneth A. Grace

Each and every mining operation from a simple sand-and-gravel pit to the largest integrated mine-mill-concentrator-smelter-refining complex has, as its foundation, a quantity of extractable natural resource the reserves. Without reserves, there is no mine, and any concentrating or extracting plant, no matter how sophisticated, is simply so much scrap metal. And, of course, without resources there are no reserves. It is remarkable, therefore, especially in this age of careful planning, high quality engineering, and state-of-the-art financial analysis, that such a fundamental and vital item is so little understood and the subject- of so much confusion. Time and time again it has been the experience of the author, when called in to a mining operation that has run into trouble in reaching projected production targets, to find that the designed-for tons were not reaching the concentrator/extraction plant, and/or the grade of such tonnage was substantially below the forecast and design grade of the plant. The mill blames the mine for delivering below standard tons and/or grade and the mining engineer blames the geologist for overly-optimistic assessment or incorrect interpretation of the deposit. The geologist blames the mining and metallurgy division for wrongly interpreting his data and conclusions, or simply fouling-up a fine orebody.

Jan 1, 1983

When a company like Lonmin, the third largest platinum producer in the world, is mining one of the most precious metals in the world, time is money. Every piece of equipment is expected to be in top shape because every minute of downtime can add up to lost profit. Two different types of platinum ore are mined and processed by Lonmin, namely Merensky and UG2. Merensky has a grade of 3.5 g/t (0.1 oz/st) and UG2 has a grade of 4.5 g/t (0.13 oz/st). The mine also produces platinum group metals (PGM), which consist of platinum, osmium, palladium, rhodium, iridium and ruthenium. Although South Africa has more than 80 percent of the world?s PGM reserves, these minerals are very scarce. Lonmin is considered a low-cost producer of these minerals, generating 21.5 t (694,000 oz) of platinum and 18.6 t (600,000 oz) of PGMs in 2012. So when the company?s Karee K3 concentrator plant in Rustenburg, North West Province, South Africa, was experiencing high operating costs on the transfer points, a solution was needed.

Jan 1, 2012

By Rongjie Kong, Shiwei Wang, Guomin Wei

Owing to the selective oxidation and uneven combustion that occur on the surface of carbon anode, some carbon particles detach and form carbon residue, which is defined as spent anode slag (SAS). The highly graphitized and toxic impurities such as fluorite ( CaF2), corundum (α-Al2O3), and cryolite ( NaAl11O17) are crucial components of SAS resource but are difficult to separate from graphite. This study developed a method of using water-soluble (emulsified) kerosene to separate the carbon particles from the toxic impurities in the SAS resource. The flotation purification approach of utilizing conventional kerosene was experimentally investigated and compared with that of using water-soluble kerosene. The results showed that with the use of emulsified kerosene, the maximum combustible matter recovery of the carbon particles was 89.86% while that of using traditional kerosene was 80.30%. The emulsified kerosene was comprehensively examined by various instruments to clarify its adsorption mechanism on the carbon particle surfaces. Because of the superior dispersibility of emulsified kerosene, it effectively envelops carbon particles with a smooth surface, oxygen-containing functional groups, and hydrophilic C–F bonds, thereby increasing the surface hydrophobicity and flotation responses of targeted carbon particles.

Feb 6, 2024

By Michael H. Inglis

The Technology Application Center, in conjunction with the U.S. Bureau of Mines Liaison Program, is studying the use of Landsat data for the monitoring of coal surface mine reclamation activities. Landsat may provide sufficient information to reduce the number of on-site inspections now required. The focus of the project has been the Navajo Coal Mine located in north- western New Mexico and operated by Utah International, Inc. On October 15, 1977, a field team recorded spectral measurements at the mine during the time of Landsat's overpass and a corresponding aerial photographic flight. Training sets were selected from the ground and aircraft data representing vegetated, graded, ungraded and natural environments. A supervised classification of the data was performed by the Stanford University Remote Sensing Laboratory then correlated to aerial photos and mine maps. The results, to date, have been very encouraging.

Jan 1, 1979

By Nathaniel Wollman

About nine years ago the President's Materials Policy Co commission under the chairmanship of William Paley released its report entitled "Resources for Freedom." Not long ago the Senate Select Committee on National Water Resources under the chairmanship of Senator Kerr released a study entitled Water Supply and Demand. Both reports contained projections of future water user the report for 1975, and the Select Committee print for 1980 and 2000, It is my task to compare the two reports. In the initial letter from Mr. Kazmann arranging for thus session he suggested that I present "a critical evaluation of the Paley Report's section on water ?ten years later,? which might include a comparison of predicted and actual water-use rates and would spotlight the assumptions which lead to errors in the predictions , . ." It is possible to compare the results of both studies, and it possible to explain art of the differences that can be found between them. The remainder must remain shrouded in doubt, since the Paley Report did not give all details of the methods used in estimating the com¬ponents of water use.

Jan 1, 1961

By Muhammad I. Kabir

A new minitest of in situ uranium leaching processes at reservoir conditions is proposed. The test which consists of a single observation/ production well and two observation wells is designed to permit the evaluation of both restoration and leaching parameters. It is shown that by using a straight forward history matching procedure, sometimes called a type curve analysis, both the rate of leaching and the ultimate uranium recovery can be evaluated based on the results of the test. Type curves are presented for the case in which the reaction rate is kinetically controlled and there are no other minerals competing for oxidant. Other situations can be approached using the same techniques as those presented here.

Jan 1, 1981

By Ray Nivens, Umit Turunc, Caroline Sui, Nick Morrison, Douglas Steiner

"In most copper mines and concentrators, mill water is continuously recovered and reused, with fresh water added to make up for losses. When mixed, these water chemistries can lead to severe scaling, especially in pipes, tanks and pumps on the mill water supply side, reducing flows and causing significant production losses.At KGHM Robinson Nevada Mining Company, increases in the fresh water addition ratios resulted in severe scaling problems and premature pump failures thereby jeopardizing plant production. What initially appeared to be a few isolated scaling events eventually unfolded into a recurring pattern of water supply-related production losses with increasing severity. Through completion of detailed root cause analysis, chemistry modeling, laboratory work, in-plant testing and system engineering, the mechanisms of scaling were identified and addressed.Advancements in fresh water addition practices and antiscalant application methods resulted in a stepwise reduction of the mill water scaling. Cost savings and production benefits were significant to the plant’s financial metrics.IntroductionThe production of mineral and metal concentrates using the flotation process requires large quantities of water. Flotation is utilized as the primary means for beneficiation with sulfide ores. Mined ores are crushed and ground into a slurry of 20-55% solids. For each ton of ore, 400-900 gallons of water1 are needed to supply the grinding mill. Additional water is needed in the flotation circuit as well. With many modern mills operating at2 11,000-165,000 tons/day, water supply volumes can be upwards of 3,000 gpm to 100,000 gpm of flow.For plants operating at or above capacity, disruptions and restrictions in water supply flow can have a direct impact on the production and recovery of the metal. Water supply flow can be limited for a wide variety of reasons but of interest are those limitations that are due to mineral scaling. Mineral scaling is the selective point precipitation of inorganic species above saturation concentrations. Precipitated species form flow-restricting deposits in the mill water system (tanks, pumps, pipe and valves), that will eventually impact water supply to the concentrator."

Jan 1, 2017

By H. R. Butler, J. F. Church, A. T. MacGibbon

Introduction Inco is the major North American nickel producer. Initially based in Sudbury, Ontario, its past exploration activity was directed toward finding new nickel deposits. New nickel sulfide discoveries outside Sudbury have included Thompson, Manitoba; Shebandowan, Ontario; and Widgiemooltha in Western Australia as well as a host of nickel laterite deposits. The company is currently diversifying into other commodities, including gold. Inco's exploration department participated in uranium discoveries in Saskatchewan and chromite discoveries at Tiebaghi in New Caledonia. In addition, it found new gold deposits at Lupin, Northwest Territories; Crixas, Brazil; Hoyle Township, Ontario; and Casa Berardi in Quebec. Crixas and Casa Berardi are currently being evaluated by underground exploration. Figure 1 shows some Canadian Shield gold locations where Inco is or was an active participant. Base metal developments Base metal exploration in shield areas has been greatly eased by applying scientific studies. Archean nickel sulfide deposits have been found using komatiitic-flow models (Fardon, 1971). Volcanogenic massive sulfide model has been applied to copper-zinc deposits (Sangster and Scott, 1976). Such deposits were subsequently seen developing on the sea floor through black smokers (Spiess, MacDonald, and Atwater, 1980). Sedimentary processes were recognized early as important in ore formation, particularly in the southern hemisphere (King, 1976). And many ore deposits are now regarded as a simple part of the geological column (Stanton, 1960 and 1972). Petrographic work on alteration patterns in and around ore bodies was used to develop standard porphyry copper models (Lowell and Guilbert, 1970). Epithermal models for precious metals followed. Stratigraphic zonation patterns have been formulated for base metal deposits, including keel facies, ore facies, and cap or distal facies. Gold developments The work on base metal deposits naturally spilled over into precious metal exploration when the gold price was allowed to float on world money markets. Early work on elements associated with gold deposits, especially arsenic, tellurium, selenium, and mercury, pioneered more detailed geochemical work (Bagby and Berger, 1985; and Groves, Ho, and Houstoun, 1984). Geochemical patterns have been recognized around microfine gold deposits. And the study of gold precipitation patterns in modern geothermal systems has helped understand gold deposition. In the late 1960s and early 1970s, it was noticed that numerous Archean banded iron formations contained anomalous gold values. From this and other observations, the syngenetic exhalite gold model has developed. Gold deposits also occur along shears in some plutons such as the Belmoral mine in Quebec. This indicates the importance of epigenetic processes in ore formation. Shield ore settings Initial studies recognized that the major gold camps in the Canadian Shield were mostly in greenstone belts and found along "breaks," especially zones of faulting and sedimentation. Gill (1948) wrote, "Only recently, as a result of detailed mapping, has the importance of major schist zones such as the Larder Lake, Cadillac, Porcupine Creek, and Destor Breaks been recognized. These zones of persistent adjustment mark broad belts favorable for ore occurrence." The importance of shearing in ore location and regional greenstone stratigraphic position close to late sedimentary packages was clearly understood. And structural models have been further developed for some Canadian ore deposits (Hubert, Trudel, and Gelinas, 1984). In the Beardmore-Geraldton camp of northwest Ontario, the importance was soon recognized of fold noses in banded iron formation, as localizers for gold ore. This importance had also been recognized in Western Australia,

Jan 2, 1987

By O. Tranbarger

In aging tunnels, wall and roof deterioration can eventually result in defects that must be detected and repaired to maintain safe structural conditions. In investigating tunnel defect conditions, a specialized FM radar system was developed with a programmable VHF and UHF operating sweep range for optimizing the penetration and measurement capabilities. The new FM radar technology was tested in two aging brick-lined tunnels in New York City. Test results showed that FM radar signals could penetrate eight courses of water-saturated brick and that the original steel liner outside the tunnel walls was intact.

Jan 1, 1985

By Daniel Saramak, Agnieszka Saramak

A big issue in crushing and grinding operations in raw materials handling is high energy consumption and low breakage effectiveness. According to the Legendre [7], only 10% of energy input is directly consumed on the feed material breakage, while the remaining portion is dissipated in the form of heat and noise [8]. In the industry of limestone powder production, the grinding operations constitute integral part of technological circuits, and the energy consumption in operations of industrial comminution consume as high as 2% of world energy [14]. High-pressure grinding is the technology with proved energy benefits both in ore processing circuits and in limestone grinding. The promising results concerned mostly the achieved energy savings and good results of material breakage were achieved and demonstrated in numerous investigations [1,3,12]. However, it appears that a proper selection of operational parameters of the press devise, determination the feed material characteristics and adjustment of process course san be of a key-significance in improving an effectiveness the HPGR operation. Operational parameters of devices and process course should be verified towards the characteristics of the feed material, which mainly applies to the particle size and shape of the feed material and its moisture, and also mineralization in case of ores [2,4,9]. There are various investigations concerning an impact of the operational pressing force on comminution results which mostly refer to the determination of energy consumption and crushing ratio [5,6,10,13]. Investigations on the moisture content are less common, however their results suggest that, in general, the HPGR feed with higher moisture shows the tendency to higher comminution intensity, while the energy consumption increases together with increasing of feed material moisture. Investigations on olivine sand feed [11] showed that crushing ratio decreases for higher moisture, especially when the material is crushed at higher pressing force. HPGR devices, however, shouldn’t be regarded as a unique and perfect solution for comminution of each type of material. But they indeed may bring technological and economic benefits, comparing to conventional crushing and grinding machines, resulting in more favourable breakage of material particles and lower consumption of energy per unit mass of processed feed material.

Feb 1, 2025

By Stuart Lister

"When MacLean Engineering chairman and founder Don MacLean got the first question from a minesite about the possibility of addressing ventilation limits through incremental fleet electrification, he was intrigued. It was back in 2015, and the MacLean scissor bolter was already diesel-electric (jumbo trailing cable), so it made sense to him that if they could engineer a battery drive system for the unit’s tramming cycle, they would have the inaugural electric vehicle (EV) MacLean unit.At that time, there were not any entirely diesel-free hard rock mines in existence on the planet, and that remains the case to this day — although the Borden project in northern Ontario is progressing toward that goal (see page 33). This meant there was essentially zero market demand for battery electric vehicles as well as a complete lack of battery technology to address the battery electrification of heavy haulage. Heavy haulage is the part of a typical mine’s mobile fleet with the largest footprint when it comes to diesel particulate emissions, greenhouse gases and wasted energy in the form of heat.Three years later — the wave of battery electrification that is currently picking up speed across the mining industry promises to hit full swing by the early 2020s when a slew of new build, diesel-free mines will start construction. But this movement toward emissions-free mobile fleets is not a completely new phenomenon. Instead, it is an updating of mining technology from a previous generation. What is going on now is the re-electrification of mining. Up until the 1960s, early generations of battery technology (lead acid) and electric locomotive systems were the norm for material and ore haulage in Canada and elsewhere.The thought of a coming paradigm change in mining was particularly pertinent to Don MacLean back in 2015, as he had been part of the era that ushered in the first generation of rubber-tire diesel equipment, when he was a divisional foreman with Inco in Sudbury in the 1970s. He was part of the operating team that was tasked to build a rail loop on one extraction level of the mine. At that time, events on the ground overtook the project, as diesel-powered mobile equipment became a viable option. Once the first diesel scoop was introduced at Creighton #3 shaft, it was clear what the power, haulage capacity and mobility could do for operations and that era of electric rail haulage underground was effectively over."

Jan 10, 2018

By Lance Rasband, Richard Hanke, John Starcevich

"Mining on Seattle’s SR99 tunnel began in July of 2013. Initial mining progressed slowly through a 4.5 m (14.9-ft) thick fiber-reinforced concrete headwall before immediately entering the first of three planned safe havens. Once through the headwall and safe haven the machine would move through roughly 122 lineal m (400 ft) of jet grout improved soil at a rate of slightly more than 1.6 m/d (5.3 ftpd). It was anticipated that once mining has passed through the improved area, “Bertha” – now the world’s second largest tunnel boring machine (TBM), would be moving at a rate of almost 11 m/d (36 ftpd). By the end of October 2013, Bertha had mined roughly 131 m (430 ft), averaging 1.4 m/d (4.7 ftpd), and had begun mining within native soils. By the start of December 2013, tunneling had reached the 244 m (800 ft) mark and Bertha was averaging 3.6 m/d (11.9 ftpd), achieving as much as 12.8 m (42 ft) of progress on given days. Unfortunately, on Dec. 6th, 2013, Bertha began to stumble and all progress quickly came to a halt.Initial reports stated an obstruction had stopped Bertha in her tracks. The preliminary investigation involved installation of 10 deep dewatering wells to reduce the hydrostatic pressure within the ground around the TBM, to allow the contractor’s personnel to inspect the cutter head from within and also to investigate for the presence of obstructions at the face of the cutter head. During inspection, the contractor’s crews found fragments of steel pipe entangled in the cutter head. The steel was apparently from an abandoned 254 mm (0.9 in.) diameter monitoring well casing, previously installed by the Washington State Department of Transportation (WSDOT) to monitor groundwater conditions for the design and planning of this tunnel project. After the steel was removed from the cutter head and cleared from Bertha’s path, she attempted to move forward but was only able to generate a slow crawl."

Jun 1, 2016

By D. A. Knight

The property is located in the Porgera Valley 600 Km North West of Port Moresby. The remote location is 2500 m above sea level. The mine area has 3,600 mm of annual rainfall and a temperate climate with temperatures ranging from 10" C to 22° C throughout the year. Alluvial gold was reported in the Porgera area in 1938 and has been an important source of revenue for the area for many years. Intermittent exploration was carried out until the 1960's when Placer (PNG) Pty. Ltd. with Mt. Isa Mines commenced an extensive exploration program. The property was brought to production in 1990 by the Porgera Joint Venture group consisting of Mount Isa Mines Ltd, Rennison Goldfield Consolidated Ltd. and Placer Dome Inc, each with a 30% ownership and the Government of Papua New Guinea with a 10% share. Placer Dome Inc. is the manager of the property with construction under the direction of the Placer Dome Technical Services group.

Jan 1, 1992

By Yuting Xue, Taghi Sherizadeh, Mark Van Dyke, Dogukan Guner, Khaled Mohamed

The Coal Pillar Rib Rating (CPRR) technique has been developed to assist in rib support design in underground coal mines. One major challenge of the data collection process is the measurement of coal strengths in the field. Schmidt hammer has been verified as a useful tool to determine coal strength. An alternative approach is to obtain the representative strength of coal mass by determining the coal lithotypes in the field based on the coal brightness profile by experienced geologists or mining engineers. In this paper, image processing techniques have been used to quantify the texture of coal images of different lithotypes with the purpose of classifying coal lithotypes. The coal images were collected from the pillar ribs with exposed surfaces in underground coal mines, and the coal lithotypes were identified when taking the images. The method of Gray-Level Co-Occurrence Matrix (GLCM) was used to analyze the textures of coal images of different lithotypes, and the texture parameters, such as contrast, homogeneity, energy, and entropy, were compared. The results show that the images of coal with different lithotypes have different textures, which can be quantified through the image processing. The results from this study demonstrate the potential of classifying coal lithotypes using rib photos and easing the data collection process of CPRR.

Feb 1, 2024

By T. Dombrowski

Acid-activated montmorillonite is used worldwide as a catalyst and as a sorbent for the enhancement and purification of petroleum products as well as vegetable and animal-based fats. The solid-acid character of the activated montmorillonite is imparted by the manufacturing process, giving it unique properties that are exploited in these industries. Several international companies and a multitude of local clay producers are focusing on improving the efficiency of their standard and specialized products. This paper will describe the use of acid-activated montmorillonite in traditional sorbent applications, as a solid acid catalyst, and other new uses.

Jan 1, 1997

By Hajime Kitamura, Nobuharu Isago, Yuta Yamanishi, Kosuke Kawata, Hiroshi Yagi, Akira Matsuoka

Mountain tunnels are generally considered to be stable during earthquakes, however, it is known that the portal areas are prone to seismic damages. Characteristics in portals such as the location of the slope, modulus of ground deformation, and the change of overburden are different for each tunnel, and damage degrees are unclear. In this study, we reproduced the seismic behavior to investigate the effect on the tunnel portal by considering some parameters above, using simple static model tests and numerical analysis. As a result, the conditions of the slope condition and minimum distance from slope was confirmed to influence on the mechanical behavior of the tunnel portal during earthquakes.

Dec 1, 2022

By B. P. Bellport

This paper summarizes the Bureau of Reclamation's experience in the use of boring machines to excavate six major tunnels on the Bureau's water resources development projects in the western United States. The summary of experience is presented as a compilation of brief case studies for each of the six tunnels. Each compilation presents data on the tunnel dimensions, geological characteristics of the excavated rock, the tunneling machine used, machine operation, muck handling, method of tunnel support, ventilation system, and related information. The listing of the six tunnels in Table 1 reflects a diversity of tunnel lengths and diameters. However, despite this diversity of dimensions as well as the variety of rock encountered during excavation, the six tunnels have one major characteristic in common: their excavation was significantly expedited by the use of boring machines. Beginning with the 10,079-foot-long Tunnel No. 1 on the Navajo Indian Irrigation Project in New Mexico - the Bureau's first tunnel to be excavated by a boring machine - the boring machines, or "moles," have demonstrated their effectiveness in rapid and economical tunnel excavation. Tunnel No. 1, virtually 2 miles long, was bored through in 9 months, an unprecedented achievement in Bureau engineering experience, as compared with tunnels previously excavated by conventional means. Boring of the 45,630-foot-long Blanco Tunnel and the 26,610-foot-long Oso Tunnel, both on the San Juan-Chama Project in Colorado, set world records in rates of excavation,l/* Two days of exceptional progress highlighted the

Jan 1, 1970

By Victor F. Hollister

This first section of case histories of mineral discoveries, Vol. 3, covers some of the milestones in porphyry copper and skam exploration successes. It was during the era of these discoveries that large, complex exploration departments emerged as permanent adjuncts of large mining companies. The discoveries helped shape how and where exploration activity was conducted. Probably the most important factor in exploration success is management. Few management people are mentioned in this section or in any exploration history, yet the distinction between success and failure ultimately rested with the decisions they made. One of the most successful groups was initiated by Roger Straus and Herbert Brownell when they sought to make Asarco into an important metal producer. Relying on Clem Pollock and L.H. (Bill) Hart to identify and push worthwhile projects, the Asarco management remade the company. Asarco will benefit from exploration successes com- pounded by that team for years to come. Duval is an example of a management that decided to add metal production to its industrial minerals output. When Page Morris was president, that company opened three major porphyry copper mines and became an important factor in metals. Under the Monis management team, Duval became a leader in exploration. At the other end of the scale are managements that snatched defeat from the jaws of victory and by so doing changed the character of their companies in other ways.

Jan 1, 1991

By George B. Rice

In a recent speech in Pittsburgh, Dr. George Keyworth, the President's Science Advisor, made a statement which I believe deserves our very careful consideration. Dr. Keyworth said that there is no energy crisis. The crisis, he explained, is simply that people refuse to accept the solution. The solution which Dr. Keyworth has in mind is increased utilization of our abundant supplies of solid fuels and, in particular, uranium. I share his view concerning the solution to our energy needs. The use of uranium fuel is a safe, clean, and dependable means to generate our electric power. It is time that we addressed the real energy crisis: the refusal to accept the nuclear solution. The reason for the refusal is not difficult to find. It is nihilistic thinking about risk. Under this thinking, we assume the worst possible case and act accordingly, simply because we cannot prove to a total certainty that nuclear energy is perfectly safe. If this absolutist approach were generally applied throughout our society, there is no doubt all of us would soon be sitting around our campfires fearfully holding the wild animals at bay with our trusty spears. Today I am here to enlist your support in reversing the regulatory trend that threatens the very extistence of the nuclear power industry. As distinguished scientists, engineers and businessmen, you can use your influence to help bring rational regulation to the industry. Our industry supports strong safety and environmental protection programs. We understand the need for and do not object to reasonable regulation. Many anti-pollution measures can be practical to implement, cost effective and highly successful in minimizing environmental impacts. However, it is a fact of life that in the field of health and safety regulation, the law of diminishing returns operates with a vengeance. Absolute or near-absolute safety is impossible and any attempt to achieve it is intolerably costly. Fixation on absolute safety is particularly acute in the regulation of the nuclear power industry. Government Agencies, overly anxious to allay the irrational fears of those opposed to nuclear power, are literally regulating the industry to death - exactly the result sought by the anti-nuclear groups. Dr. Robert L. DuPont wrote in a recent issue of [Business Week]: "The nuclear power industry has been virtually stopped in the U.S. [because of fear]. This is true despite the fact that for more than 20 years the commercial nuclear industry has operated under unprecedented public health scrutiny and that to date there have been no radiation-related injuries, let alone deaths, suffered by any member of the public."1 I believe a useful way to convey the nature of the problem faced by the nuclear industry is to review an example of [unreasonable] regulation. While the example relates to our domestic industry, I am certain there are similar situations in other countries. For the example I will use the Nuclear Regulatory Commission's recently issued regulations governing the stabilization of uranium mill tailings.2 These regulations, known as the Uranium Mill Licensing Requirements, specify, among other things, that radon emanation from uranium mill tailings be limited to no more than 2 pCi/m2-sec. First, one must understand that this standard will have virtually no impact on the total amount of radon to which the public is exposed. Radon emitted from even completely unstabilized tailings piles is a tiny fraction--much less than 1%--of the amount of radon released from natural soils in the United States.3 In fact, it is far outweighed by natural variations in the background flux. For example, changes in the level of the Great Salt Lake in recent years have had [eight times] as much effect on the amount of radon released into the Salt Lake City regional air than the annual release from the Vitro Mill tailings pile located in that city.4 Nevertheless, NRC claims that the standard is required to protect the public. The Commission admits, however, that there are no studies which establish that exposure to radon at the low levels associated with uranium mill tailings will result in any adverse health effects.5 In the absence of actual evidence, the Commission assumes that some such effects will occur on the basis of the linear, non-threshold model.6 Employing this model, NRC calculates that the maximum hypothetical risk for the average member of the population is only about 1 in 70,000,000 from the radon that would be emitted from [three times] the number of mills now in existence, even if the tailings produced through the year 2000 are left unstabilized.7 NRC has elsewhere explained that this level of risk would be equivalent to the risk posed by "a few puffs on a cigarette, a few sips of wine, driving the family car about 6 blocks, flying about 2 miles, canoeing for 3 seconds, or being a man age 60 for 11 seconds." This level of risk is [de minimis] in comparison to other risks commonly and readily incurred in our society.9 Moreover, even this remote risk is overstated. A group of prominent health physicists, including experts from the Department of Energy, The Environmental Protection Agency, Britain, Canada and Germany recently published a study indicating that the risk to the public per unit exposure to radon can be no greater than one-third that suggested by the Commission, and [may in fact be zero].l0 Regulators routinely rationalize the need for their regulations. For example, NRC attempts to justify the radon flux standard because it is necessary to reduce the risk to someone who builds a house on top of a tailings pile. This possibility, however, is totally unrealistic because the Mill Tailings Act requires that stabilized tailings be transferred to

Jan 1, 1981