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By Bruce F. Grant

This report discusses research being done by the Petroleum and Natural Gas Branch und the Applied Physics Branch of the Bureau of Mines to deter-mine the most effective uses of explosives in shooting oil and gas wells, as measured in terms of rates of production from the wells. An experimental investigation of the effects of detonating explosives in shallow holes drilled in rocks, chosen to be similar to those forming oil and gas reservoirs, forms the basis of this study. Records obtained from strain gages placed in the rock around the experimental shots permit determination of the generation and propagation characteristics of the strain wave. Water-injection tests made on the test holes before and after shooting allow the increase in fluid conductivity resulting from the shot to be determined. By rotating these data to the physical properties of the rock, and by conducting shooting experiments over the range of rock types common to oil and gas reservoirs, it is expected that relationships between the fluid conductivity and the properties of the explosive and rock can be developed and used for designing efficient shots for oil and gas wells. Four series of experiment.al tests were completed during the summer of 1949 and are described herein. The results of these tests confirmed the feasibility of the experimental approach and permitted outlining the plans for future research discussed in this report. This report is presented to acquaint industry with this research program and the progress to date, so that the Bureau may have the benefit of suggestions from interested readers.

Jan 1, 1950

By R. D. Pehlke, J. F. Elliott

The equilibrium pressure of nitrogen gas over pure silicon metal and silicon nitride has been measured in the temperature range 1400° to 1700°C. From the experimental data, the standard free energies and enthalpies of formation of Si3N4(a) have been calculated as functions of temperature over the above temperature range. Utilizing data in the literature and the results of this investigation, the specific heat, molar enthalpy, molar entropy, standard enthalpy of fornation, and standard free energy of fornation are estimated for the temperature range 298° to 1400°C. THE high-temperature thermodynamic properties of many metallic nitrides are not well established at present. This is a serious deficiency because nitrogen and nitride-forming metals are important alloying additions to steels, and knowledge of the interaction between nitrogen and these elements is essential to a better understanding of the behavior of steels. Metallic nitrides also are used as refractory materials. Consequently, the investigation reported here was undertaken to provide more complete information on the standard entropy and free energy of formation of silicon nitride. The experimental technique provided a direct measurement of the equilibrium pressure of nitrogen gas in the range of 1413 to 1700°C for the reaction: 3 Si(1) + 2N2 (g) = Si3N4 (a) [ 1 ] and below 1413oC for the reaction: 3Si(c) + 2N2(g) = Si3N4(a) [2] APPARATUS The experimental system consisted of a crucible assembly, a reaction chamber, and a gas supply and vacuum system. The Crucible Assembly which contained the equilibration specimen and molybdenum radiation shields with a susceptor for induction heating is shown in Fig. 1. Two covered, high-purity alumina crucibles, one nested within the other, contained the susceptor, shields and specimen. Central openings in the upper shield and crucible covers permitted on optical pyrometer to be sighted into the central cavity of the specimen. The specimen itself was a 5/8 OD by 1-in.

Jan 1, 1960

By Helmut Mischo

For more than 100 years, diamond mining has been Namibia?s most important mining sector. Today, it provides the highest foreign currency income for the country?s development. Since the late 1970s, offshore mining of diamonds has gained more importance and now more than 60 percent of Namibia?s generally high-quality stones come from those offshore deposits, with a steady increase expected for the coming years. Diamonds in Namibia The mining industry is one of the three pillars of the Namibian economic development, along with tourism and fishing. Diamond mining is one of the two main mining activities in Namibia and diamond mining operations are rapidly moving from onshore to offshore deposits. This article provides a comprehensive overview of the current and future situation of the Namibian mining industry, with a special focus on the tasks and new technical developments for the successful excavation of beach and marine diamond deposits. The different deposits and the adequate applied mining technologies and methods are shown in examples.

Jan 1, 2011

By Henry S. Washington

I. INTRODUCTION. DURING the last twenty years or so the chemical investigation of rocks has made great advances, and it is now generally recognized that a knowledge of the chemical composition is as essential as that of the texture or mineral composition-if not more so-for the proper classification of rocks and study of their origin and relationships. Rock-analyses have vastly increased in numbers and, what is of greater importance, in quality. New and improved methods permit of greater accuracy than was possible in the early days, and the list of chemical constituents frequently determined has risen from the seven or eight of the greater part of the nineteenth century to twenty or more. Indeed, rock-analyses with determinations of so many constituents are now commonly made by the chemists of the United States and Australia, while in Germany, Great Britain, France, and Italy the rarer constituents are determined more frequently than formerly. As a consequence of this modern, accurate work, it has been discovered that some elements which were formerly supposed to be rare are of wide-spread occurrence and are often present in considerable amount. The fact is further being developed that the elements tend to show certain relations of occurrence or abundance in connection with each other. This is a fact which is applicable to the rarer elements, and which also finds a broad geological and petrological expression in the recognition of petrographic provinces. We are beginning to obtain some definite, though as yet rudimentary, knowledge of the distribution of the elements among igneous rocks. Some of the results along these lines obtained by study of the vast accumulation of analytical data now available are well known to petrologists, while others do not seem to be so gener-

Sep 1, 1908

By Edna A. Dancy, Gerhard J. Derge

The specific conductance of FeOx,-CaO melts in contact with iron was found to decrease from 200 ohm-1 cm-1 for FeO, to 40 ohm-1 cm-1 for a melt containing 26.3 pct CaO at 1400°C. The temperature coefficient was positive at all compositions, but became smaller at high CaO contents. Current efficiencies for electrolysis increased from 2.5 pct in FeOx to 17.3 pct at the high CaO composition, indicating a change from predominantly electronic conduction to conduction with a substantial ionic contribution. It was shown that Ca++ ions as well as Fe++ ions carry the ionic current. A subsidiary investigation on the apparent effect of atmospheres of argon, helium, and nitrogen on the electrical conductivity showed that this could be correlated with surface temperature losses, which varied with the thermal conductivities of the gases and resulted in precipitation of metal by the reaction 3 Fe++ = 2 Fe+++ + Fe. The work described in this paper is offered as a contribution to the general fund of knowledge concerning metallurgical slags. Measurement of electrical conductivity and electrolysis are comparatively trouble -free methods for investigating molten materials, but, although these methods had been used for complex slags, it was not until the work of Bockris et al.1 that the approach of examining simple binary slag systems was employed, and CaO-SiO2, MnO-SiO2, and Al2O3-Si9 were studied. Two groups have performed work of particular relevance to the present investigation. Inouye, Tomlinson, and chipman2 studied the conductivity of wustite as a function of temperature and of the addition of 5 mol pct of a number of oxides, including CaO. They concluded that molten FeOx in equilibrium with iron is a semiconductor. Simnad, Derge, and ceorge3 demonstrated the ionic nature of liquid iron silicate slags and also concluded that, although the conductivity of FeOx in equilibrium with iron is predominantly electronic in nature, there is a small ionic contribution. The work reported here on FeOx,-CaO slags consists of three main parts, namely, the determination of the specific conductance over a wide composition range, an investigation into the nature of the conductivity through current-efficiency measurements over the same composition range, and an attempt to identify the current-carrying ions, as well as a subsidiary investigation on the apparent effect of the nature of the inert atmosphere on the conductivity. EXPERIMENTAL Materials. The slags, varying in composition from FeOx to 27 pct CaO, were prepared by heating reagent- grade Fe2O3 in an ingot iron crucible with a suitable amount of CaCO3 and, in some cases, powdered iron, in air. This prefused material was then used for the runs. At the end of each run the cell was removed from the furnace and quenched by immersing the bottom half in water. After crushing, the slags were analyzed for calcium and total iron by the usual wet methods. The oxygen content was obtained by difference. Specific Conductance: Apparatus and Method. Fig. shows the experimental setup, with the conductivity cell and leads of ingot iron. The standard four-probe method for measuring high conductivities was used. In this, the potential drop across the unknown resistance is compared with the potential drop across a known resistance connected in series, i .e., same current through both resistances. Thus there are both current and potential leads to the center electrode and to the crucible, which acts as th other electrode. Both ac and dc circuits were available for the measurements; they have been described in earlier work performed in this laboratory.4,5 The geometry of the cell was such that the center electrode was equidistant from the bottom and sides of the crucible. This ensured that the current path was the same irrespective of the magnitude of the conductivity of the material in the cell. Cell constant were measured with KC1 or NaCl solutions, which have considerably lower conductivities (0.0013 to 0.25 ohm-' cm) than the slags, and this precaution in design made sure that the determined cell constants applied to the cells with contents of any conductivity. The cell-constant determinations were made with the ac measuring circuit to prevent polarization. The four-probe method eliminates lead resistance but not the resistance of those parts of the center

Jan 1, 1967

By W. L. Dalke

The Minntac complex is a facility for production of iron ore pellets located on the Mesabi Range at mountain iron, Minnesota. It consists basically of a mine, crushing plant, concentrator, and a pelletizer producing twelve and one-half million tons of pellets annually. This paper deals with some of the aspects of the grinding circuits; but prior to that discussion, it might be well to briefly describe the flow of material in the operation. The crude ore, containing from 20% to 25% magnetic iron, is mined by 14-yard electric shovels. .the blasted ore is loaded directly into 50-yard side dump railroad cars and hauled to the crushing plant. Crushing is done in three stages, originally, two 60" primary crushers; four 7-foot standard secondary crushers; and six 7-foot short head tertiary crushers were installed, when the plant was expanded to double its capacity, five secondary and ten tertiary crushers were added. These were duplicates of the original 7-foot standard and short head crushers used in the original construction, there was no expansion of the primary crushers but a one-half-million-ton surge pile of tertiary crusher feed was added.

Jan 1, 1976

Early American history is filled with records of the search for and extraction of minerals-a Northwest passage to the treasures of the Indies-an overland route to the goldfields of California. Mining and its associated minerals industry have heralded advancing civilization throughout the ages. The two basic resources on which we all depend for our food, clothing, shelter, and other comforts are agriculture and minerals. Our endowment and how we use it; the spirit and industriousness of our people; our form of social organization all converge to make up our standard of living-our way of life.

Jan 1, 2012

By S. Grogan

Next year marks the tenth anniversary of the Surface Mining Control and Reclamation Act (SMCRA). As the U.S. coal industry scrambles to cope with serious economic difficulties, it is appropriate to examine some other difficulties that have their origin in certain provisions of that ten year old law, and that bear directly on the economic viability of surface coal mining in the west. This paper focuses briefly on three technical issues in the reclamation of surface coal mines in arid regions, and suggests that innovation can resolve these issues. The coal industry operates within a narrow legal context, defined in 1977. In enacting SMCRA, Congress listed among the purposes of the Act ?... to...strike a balance between protection of the environment, agricultural productivity and the Nation's need for coal as an essential source of energy." I maintain that such a balance has never been struck, particularly with regard to the reclamation of mines in the west. One reason is that when SMCRA was enacted its supporters were aware of uncertainties about the potential for successful reclamation of western surface mines. Over the intervening years, as a recent Congressional study report (OTA, 1986) points out, "...the risks these uncertainties may pose to the long term success of western reclamation have been reduced significantly." Unfortunately, SMCRA's enforcement agency, the Office of Surface Mining (OSM) has not yet recognized this fact, and the western coal industry is paying the price.

Jan 1, 1986

By J. S. Lee, R. K. Massarsch

"A 3.2 km long immersed road tunnel forms part of the Busan-Geoje Fixed Link in South Korea, which connects Korea's second largest city Busan, with the island of Geoje. To ensure the water tightness of the joints of the segmental tunnel structure and to limit the forces in the shear keys, the differential settlements have to be limited. This was achieved by extensive soil improvement of the marine clay below the tunnel with cement deep mixing (CDM) and sand compaction piles (SCP). This paper focuses on the characteristics of the marine clay, the basic design principles, layout and constructional issues of the CDM soil improvement, and numerical and numerical analyses to predict settlement and stability.INTRODUCTIONThe Busan-Geoje Fixed Link consists of two short cut & cover tunnel access ramps, a 3.2 km long immersed tunnel (Figure 1) and two long span cable stayed bridges. The tunnel consists of eighteen concrete elements each of 180 m length having a rectangular cross section of 26.5 m in width and 10 m in height. The tunnel elements are cast in a dry dock on shore and floated out to the sea, immersed in their final positions on a gravel bed in pre-excavated trench and connected to each other by a dual gasket system. The water depth was up to 50 m making the tunnel of the deepest yet constructed. After immersion, the tunnel is protected by backfill material at the sides and rock armour on top. Each tunnel element consists of eight 22.5 m long segments. The joints between the segments and between the tunnel elements are equipped with EDPM water stops, Omega seals and concrete shear keys. The longitudinal displacement behaviour of the segmental tunnel structure in the varying ground conditions represents a complex soil-structure interaction problem which has been modelled with a FEM structural model representing the tunnel, the joints and with springs to represent the soil that are derived from the PLAXIS soil/foundation models. In order to ensure the water tightness of the joints which have limited opening capacity and to limit the forces in the shear keys, differential longitudinal settlements have to be limited. This is achieved by limiting the variations in subgrade modulus along the alignment and it in practice means that differential settlements are limited to a few tens of millimetres. Without soil improvement of the marine clay below the tunnel, long-term tunnel settlements of up to 400 mm were predicted when taking into account the likely variations in the trench profile, backfilling and uncertainties in the soil properties. Such large total settlements led to large variations in the sub-grade reaction along the alignment, which in turn resulted in significant differential settlements, unacceptable joint opening and large shear key loading. It was therefore decided to carry out extensive soil improvement with cement deep mixing (CDM) (CDIT, 1999) and sand compaction piles (SCP) (Kitazume, 2005) after studying a number of foundation alternatives."

Jan 1, 2015

By S. S. Raymond, C. R. Hayward

In reheating quenched steel to remove part of the hardness, the softening effect has generally been considered to be a function of temperature and time. The temperature effect is well known, and long before pyrometers were heard of the blacksmith was able to do a good job of tempering, by rule-of-thumb methods and experience in judging temperatures. Modern conditions, which demand steel that will withstand the severest tests, require that the heat treatment be carried out with every possible precaution to secure the best results obtainable. Pyrometers and heat-treatment furnaces of many types are on the market and improvements are continually being made so that it is now possible to regulate the temperature in heat treatment very accurately. There is still a question regarding the time that the steel should be subjected to treatment. It is customary with all operators to insure the desired temperature throughout the specimen and it is generally supposed that a longer treatment of a hardened steel produces a further softening but there are few published figures showing the exact effect of time of treatment at constant temperature. A search of the literature disclosed several brief statements that the tempering effect was a function of both time and temperature, but in no case were any figures given. The opinion is very generally held that the well-know tempering colors are accurate indicators of the degree of tempering. This is disputed by Brearley (The Heat Treatment of Tool Steel, page 102) who states: It has been said that the result would be the same in respect to both hardness and other properties whether the colors were obtained by a shorter heating at a higher temperature or a longer heating at a lower one. This, to say the least, is a very doubtful conclusion, and is certainly not borne out by mechanical tests on oil-hardened and tempered motor car steels which, after tempering for periods varying from 15 min. to 2 hr., show no very great bifferences. The present investigation had for its object the obtaining of some definite data regarding the effect of time, which might serve as a guide to those engaged in the heat treatment of steel. The Rhode Island Tool Co. cooperated by furnishing the steel and machining the test specimens.

Jan 1, 1917

By E. Onal

Mining operators are faced with complex information delivered by technology-centric rather than user-centric systems. The ability to achieve high situation awareness (SA) in the face of this data overload is a key challenge for effective decision making and information exploitation. Incidents that result in loss of revenue and even life, and compromise safety that are attributed to human error are often the result of system designs that overload human cognitive capabilities. This paper focuses on defining SA as it relates to mining operations and presents methods for improving SA through a scientific approach for electric shovel operator user interface development.

Aug 1, 2013

By Bruce Cantrell, K. L. Rubow

"INTRODOCTIONMeasurement of the contribution of diesel exhaust to respirable aerosol in mine environments has become increasingly important because of current concerns over the occupational health effects resulting from exposure to diesel emissions. In response to this, the U.S. Bureau of Mines is developing and evaluating new sampling methods for measuring diesel aerosol in underground mines. Two such techniques are being studied by the Bureau, size selective sampling and Chemical Mass Balance (CMB) modeling. These techniques use measurable physical or chemical characteristics of a mine aerosol sample to infer the amount of diesel particulate material contained in the sample.Size selective sampling is being adapted for measurement of diesel aerosol by the Particle Technology Laboratory (PTL) of the University of Minnesota under sponsorship by the Bureau. 1 It is based on the premise that diesel and mineral dust aerosol can be physically separated by size and collected during sampling using inertial impaction. An independent effort by the National Institute for Occupational Safety and Health to develop a size selective sampling technique was also sponsored by the Bureau.The second technique, CMB modeling, is being developed by the Bureau as an alternative measurement technique to referee the results obtained using size selective sampling.3 It compares measured trace element ""finger prints"" of aerosol sources with similar profiles of mine aerosol samples. From these, the portions of the sample contributed by each source can be determined. Results of these investigations in underground coal mines have confirmed that diesel and coal dust aerosol are of different size and can be measured separately using size selective sampling techniques.A major difference in diesel usage among underground mines is the requirement for exhaust gas cooling systems in coal and gassy noncoal mines. Nongassy mines usually employ limited exhaust conditioning in the form of catalytic converters, which have limited effect on primary exhaust particulate. The cooling system in most general use in gassy mines is the water scrubber. This device has little effect on most of the gases but removes particulate material from the exhaust. 5 Because of this, exhaust aerosol characteristics in nongassy mines are expected to be different. To see if size selective sampling techniques can be used in such mines, the Bureau and the University of Minnesota conducted a second study in three metal and nonmetal mines, two nongassy and one rated as gassy."

Jan 1, 1990

By T N. Little

The author contends that geoscience is presently under-utilised in the rock fragmentation by blasting process. Before we can set standards in this area, the following is required: mine geologists need to gain a better understanding of the blasting process and the blasting team needs to obtain a better appreciation of geology. Both groups need to be informed of what can be done to improve blasting outcomes, why it is necessary and how it can be achieved. By working closely together, both the geoscience toolkits and blasting expertise can be applied and focused on priority blast sensitive issues, with potential to improve mine economics and safety. Finally, and ideally, mine geologists need to take a leadership role in raw rock mass data collection and data management, and invited to take an active role in rock mass related behaviour data collection, integration and presentation.This paper attempts to provide insight into all these prerequisites for setting a new standard for collaboration and mutual learning in this strategic opportunity area. The potential for blasting to leverage downstream processes is highlighted. Blasting objectives and blast design principles are introduced along with the required rock mass related inputs. Some hazardous geological materials and environmental conditions are described, along with how they can affect operational complexity.Four case examples are used to illustrate the need for closer liaison between geology and blasting professionals. The first related to grade control blasting, aims to demonstrate how a blasting geology approach can add significant value. Case example two demonstrates how geological models and bench face analysis can assist with fragment control. The third and fourth case examples involve an overview of two case studies where timely geological and geotechnical knowledge input and intervention into blasting activities may have reduced losses due to blast initiated open pit slope collapses.CITATION:Little, T N, 2017. Geoscience input into blasting operations – let’s set a new standard, in Proceedings Tenth International Mining Geology Conference 2017, pp 375–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By V. W. Lumadi, S. Nyasha

The mining industry has yet to fully accept and embrace the strategic role of technology and innovation in successful business planning and execution. In this study, we empirically determine the factors that influence acceptance of technology solutions in the mining industry in South Africa, assess critical success factors influencing adoption of advanced technology in the South African mining industry, and explore challenges faced by the mining industry in South Africa in adopting advanced technology in its operations. Thematic content analysis is employed in the data analysis. Results show that critical success factors to the adoption of mining technology include learning culture, knowledge sharing, high labour costs, and behaviour of other firms in the industry; commonly identified challenges include inadequate engagement with external stakeholders, uncertainties, the cyclical nature of the sector, and high risk related to the adoption of unproven technology and performance systems focused on volumetric production. The study encourages mining companies to implement usage of technology. This can be properly done through regular engagement with the Minerals Council South Africa.

Apr 14, 2024

By H. Kudelka

Copper electrowinning at Duisburger Kupferhuette was introduced in March 1975. The electrowinning plant has a capacity of 10,000 mT of copper cathodes a year. The cuprous oxide feed material is an intermediate product of the treatment of the leach solutions, originating from chloridizing roasting of pyrite cinders. This material is characterized not only by a wide spectrum of accompanying impurities, but also by an unusually high level of precious metals. As the priority set was the production of high-purity cathodes. there was a need for developing a process which would be suited to treat complex leach liquors . The process adopted consist s of an oxidizing leach in spent electrolyte, followed by two- stage purification, By this means. a low- acid pregnant copper electrolyte is obtained free of elements detrimental to copper quality. Electrowinning is carried out at a current density of 200 A / m2 in the presence of 10 g/l zinc. The electrowon copper has a conductivity of at least 101.4% lACS and a softening temperature not exceeding 200°C, which makes it a suitable product for continuous casting and dip ?forming.

Jan 1, 1977

By M. Kowalczyk

The successful application of color sorting machines has established sensor-based sorting in the mineral industry in recent years and is considered today as a significant innovation in processing technology. However, we are only at the beginning of the (market) introduction. New sensor systems have been developed, which exploit material properties such as electrical conductivity, magnetization, molecular structure, thermal conductivity etc. This opens up new exciting pre-concentration and upgrading possibilities for many applications such as nickel, gold, copper and other ores as well as for industrial minerals, diamonds and other gemstones.

Jan 1, 2009

By T. Bhambhani, Mukund Vasudevan, Partha Patra, D. R. Nagaraj, P. Somasundaram

Selective Ni separation from ultramafic ores rich in serpentines has been a huge challenge in the mineral processing industry, and therefore highly inefficient. Analysis of the root causes of the challenges and consequent development of robust processing solutions were the main goals of the Cytec-Columbia. University-Vale Joint Development Program. In this context, the subject of this paper is limited to one of the key findings of this research program which is the influence of fibrous serpentines on grade-recovery characteristics. Specifically, the poor flotation behavior is characterized by an atypical reverse C-shaped grade-recovery curve.

Jan 1, 2011

By T. J. Otto, G. C. Lindeque

Productivity is improved by increasing the ratio of output to input. In an operating open-pit mine, improving the productivity of heavy mining equipment (HME) enables the unit cost of production to be reduced. To optimize HME productivity, the Kolomela open-pit iron ore mine transitioned to an enhanced short-term mine planning (STMP) process that supports the application of a manufacturing-type operating model. At the core of the enhanced STMP process is a focus on integration across the open-pit mining value chain. The interdependencies between mining activities are highlighted and emphasized, thus ensuring that mining activities are synchronized. The improvements related to HME productivity were monitored from 2019 to 2020. The utilization of mining area in the Leeuwfontein pit improved from 71% to 90%, and the blasting frequency reduced by 14% while the average blast size increased by 17%. The distance travelled during shovel relocations between mining phases reduced by 16%, and the lost time associated with drills relocating reduced by 53%. These productivity improvements resulted in an 11% increase in the loading rate of the main waste shovel at Kolomela from 0.9 Mt/month in 2019 to 1.0 Mt/month in 2020. The enhanced STMP process can be adapted to other open-pit mining operations.

Nov 1, 2021

By T. M. Yegulalp

A new explanation of the scale dependency of the strength properties of rock is presented based on the theory of extremes. A review of past work on specimen size strength relationship is followed by an introduction to the fundamentals of the underlying theory of extremes and its relationship to the scale effect on the statistical properties of the strength distribution. It is shown that the weakest link theory is directly related to extremal statistics and properties of strength distributions of rock can be derived as a function of the specimen size. Three sets of Brazilian test data are used to demonstrate the use of this approach.

Jan 1, 1992

By Emily Wortman-Wunder

While the mood at the 2013 annual joint meeting between the Pittsburgh Coal Mining Institute of America (127th Annual Meeting) and SME Pittsburgh Section (68th Annual Off-the-Record Meeting) in Canonsburg, PA was subdued following a rocky year in the coal industry, attendance was down only slightly, to 300, and overall, the meeting?s focus was optimistic about the future of coal. The conference began by addressing one of the central challenges of coal mining head-on with a keynote address on the status of safety in the mining industry. Noting that two more U.S. miners had died in 2013 than by the same date in 2012, the National Mining Association?s (NMA) Senior Vice President of Regulatory Affairs Bruce Watzman made a plea for a new approach to safety. He described the NMA CORESafety initiative, a program that promotes proactive safety measures versus a compliance-driven model. CORESafety, described in more detail on pp. 29 of this issue, focuses on developing successful ways to change company cultures of safety and behavior. Other industries that have adopted this approach have seen dramatic drops in fatalities, including the Australian mining industry, which has seen its annual fatality rate drop to nearly zero even while the number of people employed in the industry has soared. The rest of the morning?s sessions explored what is arguably the industry?s biggest challenge right now ? maintaining the social license to operate.

Jan 1, 2014