Search Documents

By B. Birol, M. N. Saridede

"Slag density is a significant factor in determining the process efficiency of the electroslag remelting (ESR) process, where calcium fluoride (CaF2)-based slag is formed synthetically to refine metal ingots. Although there are some former studies investigating the density of CaF2-containing slags, the prediction models focusing on them are applicable only to some specific systems. The present study aims to build a model to predict density for a wide range of CaF2-containing ESR slags. To investigate density for various slag compositions, CaF2-Al2O3-based and CaF2-Al2O3-CaO-based slag compositions were prepared. Additionally, some minor constituents like FeO, MgO and MnO were added to a 5:3:2 CaF2-Al2O3-CaO slag in order to investigate the effects of these constituents on the slag. The volumes of the prepared slags were measured in a tube furnace at 1450-1550 °C using the sessile drop technique, and their densities were calculated. The results showed that for the slags, density is related to optical basicity, and therefore a prediction model based on an Arrhenius equation was built. The model was tested with data from literature, and its limitations and validity are discussed.IntroductionThe electroslag remelting (ESR) process is a refining method in which a metal ingot is remelted under a synthetic slag. These synthetic ESR slags are mainly composed of calcium fluoride (CaF2), calcium oxide (CaO) and aluminum oxide (Al2O3). Other constituents like iron oxide (FeO), magnesium oxide (MgO), manganese oxide (MnO) and chromium oxide (Cr2O3) are added to this system in relatively low amounts, according to the type of steel ingot to be refined. The prediction of slag properties, such as electrical conductivity, viscosity and density, is crucial for the selection of the synthetic slag in order to obtain the required process parameters, like temperature, the passing time of the molten metal droplet through the slag, and metal-slag separation (Akbari, Reitz and Friedrich, 2009; Hara and Ogino, 1981; Mattar, El-Faramawy and Fathy, 2002; Mehrabi, Rahimipour and Shokuhfar, 2005; Presoly, Korp and Schneider, 2008).As slag density affects metal-slag separation in the ESR process, predicting the density of an ESR slag is important for appropriate refining and improved product quality. Although there are many studies investigating the density of slags (Akbari, Reitz and Friedrich, 2009; Aune, Hayashi and Sridhar, 2005; Hara and Ogino, 1981; Matsushita, 2011; Mills and Keene, 1987, 1981; Seetharaman et al., 2013; Shu, 2007; Shu and Chou, 2013; Sikora and Zielinski, 1974; Xu et al., 2012; Zhang and Chou, 2010), the prediction models built are generally valid for oxide-containing slags (Aune, Hayashi and Sridhar, 2005; Bottinga and Weill, 1970; Mills and Keene, 1987; Seetharaman et al., 2013; Shu, 2007; Xu et al., 2012; Zhang and Chou, 2010). These models were built on either the molar volumes of the constituents (Bottinga and Weill, 1970; Mills and Keene, 1987) or the thermodynamically calculated enthalpy or free energy of mixing, which can be applied to a system containing constituents sharing an ion, such as an O- ion for oxide systems (Aune, Hayashi and Sridhar, 2005; Hillert, 1980; Persson et al., 2007). Some recent studies modeled the density of some oxide slags on their optical basicity (Shu, 2007; Shu and Chou, 2013; Xu et al., 2012; Zhang and Chou, 2010)."

Jan 1, 2016

By PETER ROBINSON, KEVIN BARBER, OLIVER WHATNALL

The investigation and uptake of filtered tailings continues to grow around the world, but cost and scalability are deterrents for mining companies. Filtration technology that is currently in use is unable to meet the needs of many operations and projects that would otherwise adopt filtered tailings. For tailings to reach the desired moisture content for dry stacking, the majority of processes require pressure filtration, with significant upfront and ongoing maintenance costs. Given the comparative lower costs associated with low-pressure Viper vacuum belt filtration, this technology has the potential to alleviate dependency on high-pressure applications and make efficient dewatering and handling of tailings a more economic and sustainable solution.

By Agus Sasmito, SRIVATSAN JAYARAMAN SRIDHARAN, Akash Adhikari, Purushotham Tukkaraja

The amount of toxic fumes produced during blasting operation depends on the types of explosives used, product formulation, degree of confinement, conditions of use, and reactivity of the explosives with the host rock. Ammonium nitrate and fuel oil (ANFO) is still the explosive of choice due to its lower price and ease of use/loading. If not properly monitored and controlled, toxic fumes produced from blasting operations can have serious health hazards [1]. This paper presents a novel technique developed to track trapped fumes during a development blasting.

Aug 1, 2022

By M. T. Webster

Views about the proper aim of public policy are, of course, matters of perspective and debate. Regardless of perspective, one would assume some consensus around the view that public policy ought to encourage mine operators to seek independent and critical assessments of worker safety and health at their operations through voluntary auditing. However, a review of the law on this topic shows that there is little to no manifestation of such a policy. Indeed, the balance of this paper, with a couple of exceptions, is devoted to the existing legal pitfalls that should be considered before a safety and health audit is conducted at a mine. While attorneys, particularly litigators like the author, might tend to focus on the potential problems that could arise from any given situation, the fact that most of this paper is devoted to potential legal concerns associated with auditing is a realistic reflection of the current state of the law. Specifically, this paper addresses the interplay between voluntary safety and health audits conducted at mines regulated by the Mine Safety and Health Administration (MSHA), and the administrative and civil legal issues related to such audits. The paper first provides an explanation of how and by whom an audit is conducted. The paper also addresses whether voluntary safety and health audits may be considered privileged and kept confidential in administrative and civil proceedings. Finally, selected legal issues related to such audits that could arise in administrative and civil litigation are discussed.1

Jan 1, 2012

By T. Yue, Z. Gao, X. Tong, R. Liu

"Lead ions (lead nitrate) were introduced to modify the surface properties of scheelite, effectively and selectively improving the flotability of scheelite, with benzohydroxamic acid (BHA) serving as the collector. A series of experiments about the mode of addition and the ratio of lead ion to BHA were conducted and indicated Pb-BHA complexes were the active species responsible for the flotation. And two adsorption models of BHA on the surface of scheelite were established. For both the two adding methods, some kind of complexes formed by lead ions and BHA played a key role in the flotation process. Zeta potential, FTIR, and XPS studies indicated that the adsorption amount and intensity of BHA on the surface of scheetlie were larger by adding the reagents as a mixture. The mixed addition is conducive to form Pb-BHA complexes and improve the adsorption efficiency of BHA on the surface of scheelite, as well as the recovery of scheelite. INTRODUCTION Scheelite, as an important tungsten-bearing mineral, is nowadays utilized mainly by flotation (YIN and WANG, 2014; Sun et al., 2011; Gao et al., 2015; Gao et al., 2015). Flotation separation of scheelite from calcium minerals creates difficulties because of the existence of the same cation in the minerals and similar physico-chemical characteristics such as solubility, hardness, specific gravity, point of zero charge (PZC), etc. (Arnold and Warren, 1974; Deng et al., 2016; Deng et al., 2015; Ozcan and Bulutcu, 1993a; Yongxin and Changgen, 1983). The conventional collectors used in the flotation of scheelite ores are generally fatty acids or fatty acid derivatives (Bo et al., 2015; Oliveira and Sampaio, 1988; Shi et al., 2014; Sivamohan, 1988; Yongxin and Changgen, 1983). It is difficult to separate scheelite, especially from calcite, with these reagents because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface (Atademir et al., 1979; Changgen and Yongxin, 1983; Hiçyìlmaz et al., 1993; Hu et al., 2011). Therefore, it is almost impossible to separate them by fatty acid flotation without using any selective depressant. Although oleoyl sarcosine was used as a selective collector in the flotation of fluorite and siliceous scheelite ores (Ozcan and Bulutcu, 1993b; Ozcan et al., 1994), this selectivity is inadequate for a low-grade calcitic scheelite ore. Unfortunately, reagents such as organic colloids (dextrine, starch), quebracho, sodium phosphates, sodium silicate solutions containing polyvalent cations (hydrosols), etc. (Bo et al., 2015; Schubert et al., 1990; Shi et al., 2014; Yongxin and Changgen, 1983), used for calcite depression also depress scheelite to a large extent. Cationic collectors, such as amine and quarternary ammonium (Yang et al., 2015) and collector mixture (Gao et al., 2015) have been used to improve the scheelite flotation. However they have not been applied in industry due to the poor separation from silicate minerals."

Jan 1, 2017

By Gary Brierley, Lok Home

"The majority of tunnels for civil engineering applications are now being constructed using some form of mechanical excavation. Beginning in the 1960s with rock tunnel boring machines (TBM), the tunneling industry has introduced both earth pressure balance (EPB) and slurry pressure balance (SPB) soil machines; mixed soil and rock machines and a variety of different mechanical devices for the construction of small diameter tunnels. Over time, these machines have become more powerful and more adaptable to a wider variety of ground conditions; so much so that tunnels are now being constructed in ground conditions and in the vicinity of third-party impacts that would have been considered beyond the state of the art just 10 years ago. Figure 1 is an example of a mixed ground crossover TBM used successfully at Mexico City’s Túnel Emisor Poniente II.All of the above is highly advantageous for the tunneling industry, but it has also placed a much higher level of risk on the performance characteristics of the tunneling machines, on the contractors operating those TBMs and on the manufacturers of those machines. Most of the risks for a tunneling project are associated with creating the space inside of which the finished facility will be constructed. In order to create that space, the tunnel contractor must make many decisions about the best way to excavate the ground, the best way to control the ground at the face of excavation and the preferred method for supporting the ground around the tunnel in a manner that is safe for the workers and stable with respect to all of the overlying and adjacent existing structures. If it is proposed to use some form of TBM in order to build the tunnel, then the TBM becomes central to all three of these activities and becomes an integral part of managing the risks associated with these activities."

Jan 9, 2018

By İbrahim Alp, Emine Yoğurtcuoğlu

This article includes the application of roasting pretreatment by assisting the cyanidation process in the recovery of Au–Ag from Bolkardağ Gossan refractory ore and the characterization studies of the ore, roasting sample, and postcyanidation waste sample. While ore contained many metals along with gold and silver, the environment in which these metals were found was carbonate, sulfated, silicated, and iron oxide-containing deposits that have undergone oxidation. In mineralogical studies, there were Fe oxy/oxyhydroxides, Pb/Zn carbonates, and jarosite-bearing structures such as beudantite, calcite, dolomite, clay, and quartz in the ore. The sample used in the experiments was d80 = 29.6 μm, and the test parameters were determined by examining the TG analysis made to the ore. Preroasting experiments were carried out at a roasting temperature range of 200–800 °C, during a roasting period of 10.0 min. Three different samples were characterized by TG for temperature changes, FT-IR for bond structures and permeability, SEM/EDX for visual inspection of structural changes, and XRD Rietveld’s analysis for mineral % content differences. As a result of the cyanidation experiments carried out after the pretreatment, gold was recovered with 80–90% yields and silver with 40–48% yields, respectively.

Aug 21, 2023

By L. Wilfley, G. A. Calboreanu

"Wear resistant 25% Cr hard cast iron is a heterogeneous material containing 1,600 HV hard chromium carbides embedded into martensitic matrix. It is the most used cast alloy in wear operations of mining industry, chemical industry, fracking, etc. During the last decade the hard iron manufacturers increased wear resistance in the following ways: • Reduce / eliminate harmful retained austenite and chromium + carbon depleted areas especially within eutectic carbide cells. In Max5A the improved 25% Cr alloy brittle carbide eutectic cells are removed which increases toughness. • Delay delamination between chromium carbides and matrix particularly during sliding abrasion wear. Delamination commences at the weakest chromium carbide – matrix contact lines exposing chromium carbide to localized bending stresses which gradually chip carbides away. Once the chromium carbide base is removed accelerated wear degradation occurs. • Evenly randomize and avoid discontinuities in the chromium carbide network. When chromium carbides are perpendicularly positioned to the wear surface wear rate is minimized. On the contrary the highest wear rate takes place when 3D oriented chromium carbides are parallel with the wear surface. In this case chromium carbides cover top network discontinuities being just matrix supported which leads to rapid carbide cracking. The new hard iron discussed in this paper fulfils and exceeds the above requirements increasing the casting service life around 250% in various wear operations. Physical and mechanical properties of Max5A are compared with well manufactured Industry Standard 25% Cr hard iron. The paper presents practical accomplishments obtained in the USA, South America and India. INTRODUCTION The chemical composition of Max5A and Industry Standard 25% Cr are identical like specified by ASTM A532 Class III Type A requesting C = 2.0-3.3% and Cr = 23.0-30.0%. Manganese, silicon, nickel, molybdenum and copper contents are limited by maximum accepted quantities.[1] According to published data the eutectic chromium carbides chemical composition of 25% Cr hard iron is Cr = 54% and C = 8% which indicates strong depletion of chromium and carbon along chromium carbide - matrix interfaces. [2] The optimized Max5A microstructure has minimized retained austenite, is devoid of harmful carbide eutectic cells and has the most advantageous chromium carbide and secondary chromium carbide morphology. This favorable microstructure increases wear resistance, mechanical properties and corrosion resistance. The paper compares the Max5A microscopic features and mechanical – physical properties with similar properties of high quality Industry Standard 25% Cr."

Jan 1, 2017

By H. Kimura

A new technology for ironmaking based on direct gaseous reduction of iron ore concentrate is under development. The process is based on the flash reduction of the concentrate particles in a gaseous reducing agent, such as hydrogen, natural gas, a reducing gas generated by partial combustion of coal, or a combination thereof. This technology is expected to drastically lower CO2 emission and reduce energy consumption by about 38% of the blast furnace requirements. The energy savings are possible largely due to the elimination of pelletization and cokemaking. Process design and simulation using hydrogen as the reductant for iron ore concentrate have been performed. A process flow sheet composed of a flash reactor, heat recovery system, water removal system for purifying recycled hydrogen, and all connecting streams was evaluated using the METSIM software. Ironmaking using two reactors was also designed and simulated, which could reduce the total required amount of hydrogen although it would increase the complexity of the flow sheet and operation.

Jan 1, 2010

By M. Javier

In business mining, dilution is the result of the operating parameters that occur too often and cause serious consequences to mine performance, questioning TO WHOM BENEFITS DILUTION. Mining persists in changing perception of real meaning of dilution. The lack of interrelation between mineral processes and nature compromises the understanding of dilution; this absence of interrelation occurs due to the misinterpretation of nature, otherwise, Geomimic could be helpful to filling the gap of misinformation. NATURE provides LIMITED metals in low content deposits; it is a challenge to obtain them. Nature never considers dilution. Furthermore, though dilution is a human concept, dilution is accepted and promoted. Reality of dilution is in its errors accumulation that translates into technology level or status applied in nature. It is doubtful that dilution can continue surviving if it is ?meaningless?. It will discourse: Is dilution illegal? If the change occurs in the prediction of mining will prevail a different destiny, it is important to touch the cores of the business; otherwise, it would represent repetition of the same ?negative? effects, as usual. Mining defines many losses during the disturbance of nature, from NPV elaboration to the metal recovery to commerce, demanding BETTER DESIGN. This paper introduces and applies MANAGEMENT BY LOSS, as first steps, to limit risks and uncertainties in mining. As result, the management of dilution will be obtainable under mining practices which promotes its character of SUSTAINABILITY.

Feb 23, 2014

By P. A. Cornejo

Blastings always generates induced vibrations through seismic wave, these are lost energy from the blasting and therefore causing the disturbance of slopes and structures near the blast source. Most of the components of an open pit mine have to reach a physical stability, especially during its closure process. Aiming to develop a vibration prediction model using the historical records from an open pit mine located on Peru, this research has two main focuses depending on the distance from the blast source to the structure: to protect the final slopes and to protect the villagers houses. Both are based on the Devine model of the Square Root Scaled Distance (SRSD) to predict the Peak Particle Velocity (PPV). The Mid field model, where is found mainly final slopes from the pit, limited by the failure criteria of McKenzie based on the geo mechanical properties of the rock mass. The Far field model ranges distances where are located the most community households, limited by the German rule DIN 4150 for highly sensitive structures. Both scenarios resulted on a distribution abacus to limit the weight of used explosives to get the best operational advantage and structure safety.

Mar 2, 2022

By H. Askari-Nasab, B. Osei, K. Awuah-Offei

The U.S. coal mining industry consumes approximately 142 billion kWh/a of energy. The U.S. Department of Energy estimates that the industry’s annual energy consumption could be reduced by 49%. This constitutes nearly $3.7 billion of potential savings on coal production costs at 5.3¢/kWh of energy. Additionally, with climate change regulation on the horizon, any benefits from energy savings in the near future are compounded by associated reductions in CO2 emissions. Research indicates that operating conditions significantly affect energy efficiency. Modeling and simulation have been shown to be a cheap and reliable means of evaluating the effects of process interactions and operating conditions. The goal of this work was to apply stochastic process simulation to model the energy efficiency of a typical truck-and-shovel mining system and use the model to evaluate production strategies to improve energy efficiency. The research team conducted energy audits of truck-and-shovel overburden removal and used the results to develop regression models describing truck and shovel fuel consumption. The team then built a stochastic simulation model of the truck-and-shovel overburden removal operation and used it to assess a variety of improvement measures by simulation experimentation. Valid fuel consumption models for shovel loading and truck haulage have been formulated, based on the energy audit results. Valid stochastic process models of truck-and-shovel operations have been formulated to study energy efficiency. The following strategies, in decreasing order of impact, provide the most energy savings for truck-and-shovel overburden removal at the mine: (1) shorten haul roads, (2) increase shovel capacity and (3) increase shovel utilization through optimal truck matching. Additional data will be required to adequately describe operator effects on energy efficiency.

Jan 1, 2011

By Lex L. Udy

External detonation generated plasmas, highly ionized zones of reacting material ejected from the surface of detonating ex-plosive charges, are shown to be the cause of channel desensitization, i.e., the self-quenching of a detonating explosive column loaded in a borehole with an air annulus between the explosive and the borehole wall. The effects of this phenomenon on several explosive compositions and types are demonstrated and discussed. Explosives tested include aluminum sensitized and explosive sensitized slurries, ANFO, liquid explosives and dynamites. Various techniques are described that can be used to reduce or eliminate the plasma effect.

Jan 1, 1978

By Samir Kumar Pal, Rajasekar Rathanasamy, Gobinath Velu Kaliyannan, Moganapriya Chinnasamy, Sathish Kumar Palaniappan

The research examines the performance of uncoated and coated tungsten carbide-cobalt rock cutting bits. It aims to optimize process variables (cutting speed, depth, coating material) considering multiple output responses (cutting forces, specific energy, wear rate, material removed, angle of reaction forces). The study uses a hybrid optimization technique combining Taguchi design, grey relational analysis, and fuzzy logic. The optimal parameter combination was found to be cutting speed: 200 mm/s, cutting depth: 6 mm, and titanium aluminum silicon nitride coating.

Apr 24, 2022

By Juan Andres Jarufe, Carlos Cifuentes

Numerical modelling has been extensively used to estimate plastic displacement in faults and rock mass surrounding mine excavations. Particularly, for fault slip seismicity, modelled plastic displacement is usually utilized to estimate seismic potential, however these methods assume that all the displacement caused during an specific simulated excavation step, is released as a single event at each step. This representation corresponds to a conservative estimation since rock mass displacement does not occur as one single event but as an exponential distribution of many small displacements and a few large ones. When displacement is expressed as seismic magnitude, this exponential distribution is addressed as the Gutenberg Richter (GR) relationship. This paper present a method to decompose the results from numerical models into a distribution of seismic events The reconstruction of the GR relationship from modelling displacement permits not only a more realistic approximation of the expected maximum magnitudes but also provides a tool to develop a probabilistic estimation of the maximum possible magnitudes.

Apr 26, 2022

By Karoly (Charles) Kocsis, Jeff Johnson, Felipe Calizaya, Tulio Dias, Natanna Nunes

Two pressure balancing chambers were constructed at a Colorado coal mine to reduce the risk of spontaneous combustion. Each chamber was established by installing a Kennedy stopping at about 10 ft (3 m) in front of an isolation seal, and equipped with two safety doors, a nitrogen injection system, and a set of environmental monitors. Several pressure balancing tests for different ventilation conditions were conducted in these chambers. During each test, pressurized nitrogen was injected into the chamber and the pressure differentials across the stoppings and seals monitored. This study presents a summary of the results achieved, lessons learned, and the basic requirements to operate a pressure chamber effectively.

Feb 1, 2024

By W. M. Tuddenham

It would be most difficult to place a date on the beginning of the revolution in analytical techniques that we have witnessed in recent years; but there is no question that the period since the end of World War II has seen a major change in thinking with respect to control and accounting analyses. For reasons relating to competition, much of this change was brought about in the chemical industries and only more recently has begun to affect directly the mineral industries. In considering the subject outlined in the title of this paper, one might well be tempted to discuss solely the more exotic methods of control and automation which have come into being in the past short while. In this paper, however, an attempt will be made to take a broader view and consider not only the application of newer purely physical methods of control but also those phases of chemical plus physical analyses that have bearing on our industry.

Jan 1, 1962

By H. Murray

Introduction Industrial minerals are key ingredients in a large majority of domestic and industrial products that are used in our daily lives. In the 7th edition of Industrial Minerals and Rocks, fifty three industrial mineral commodities are described. A precise definition of industrial minerals and rocks is difficult. Bates (1975) proposed a definition which is widely used and is as follows: "any rock, mineral, or other naturally occurring substance of economic value, exclusive of metal ores, mineral fuels, and gemstones: one of the non-metallics". They can be igneous, metamorphic, or sedimentary and range in price from a few dollars per ton to a very high price of hundreds of dollars per ton. The growth in their production and use is closely allied with population growth particularly in countries that maintain a high standard of living. The United States just passed 300 million in population and it is predicted that by 2040 the population will be 400 million. This will result in large increases in the need for Industrial minerals. Other factors that relate to increased use of industrial minerals are increased research and development by the producing companies and better quality control. Many industrial minerals such as kaolin, barite, nepheline syenite, fluorspar, lithium carbonate, phosphate rock, potash, talc, and several others are exported from the producing countries to many users around the world which has significantly increased their use. Also, government agencies, State Geological Surveys, and Universities have contributed to their growth by their research and development activities.

Jan 1, 2007

By J. Y. Lee, J. Kang

"A selective chlorination process using cuprous chloride (CuCl) was investigated for producing high-grade chalcocite (Cu2S) from chalcopyrite (CuFeS2) feed. The chalcopyrite feed was reacted with CuCl in the presence or absence of sulfur (S) at temperatures between 900 and 1,100 K for five hours under an argon gas atmosphere. The experimental results indicate that iron (Fe) was selectively removed from the chalcopyrite feed as ferrous chloride (FeCl2) at 1,100K and the mass percentage of Fe thus decreased from 31.5 percent in the feed to less than 0.05 percent in the residue, under certain conditions. As a result, high-grade Cu2S was obtained from chalcopyrite in a single step. This new selective chlorination of chalcopyrite using CuCl as a chlorinating agent is therefore feasible for producing high-grade Cu2S.IntroductionCurrently, blister copper (Cu) is commercially produced from sulfide ores by pyrometallurgical methods. These methods entail matte smelting and converting, with the removal of iron (Fe) and sulfur (S) as slag — mainly Fe2SiO4 — and sulfur dioxide (SO2) gas, respectively.In the pyrometallurgical method, as shown in Fig. 1 (Schlesinger et al., 2011), Fe is removed through two steps at high temperatures of around 1,500 K to reduce the loss of Cu during slag formation. However, the slag still contains 1 to 8 percent Cu. Therefore, Cu in the slag is recovered by slag treatment processes, after which the concentration of Cu in the slag decreases to around 0.4 to 1.3 percent. Although Cu is recovered, the slag that had undergone the treatment processes is difficult to use as a feedstock for ironmaking owing to the small amount of Cu remaining in the slag (Schlesinger et al., 2011).In addition, large amounts of SO2 gas are generated by the oxidation of S in the current Cu production process. The SO2 gas generated is captured and used to produce sulfuric acid (H2SO4). However, despite the development of SO2 gas-capture technologies, the emission of SO2 gas is still a problem in terms of environmental considerations.Several studies had been carried out in the past to overcome the drawbacks of the current process. The extraction of Cu from sulfide ores using a chlorination process is one alternative that had been investigated by several researchers. Most chlorination processes used chlorine gas (Cl2) as a chlorinating agent at temperatures between 573 and 1,023 K under an inert atmosphere (Donaldson and Kershner, 1962; Olsen et al., 1973; Kumar, Li and Warren, 1985, 1987; Kanari et al., 1999; Kanari, Gaballah and Allain, 2001)."

Jan 1, 2017

By George A. Roche

Since our firm was established by Mr. Price in 1937, we have followed an investment philosophy which is based on the belief that investment in growth stocks is the most assured way of achieving superior, long term investment accomplishment. There are many criteria that we use to select growth companies but the most important is a combination of superior management operating in an industry with above average growth potential. This growth stock approach is the cornerstone of our investment strategy for two of the three mutual funds sponsored by the Price organization and for our private clients. However, during the past 5 years we have seen inflation accelerate due to a variety of factors including the inability of our government to meet seemingly unlimited needs with limited revenue sources. While there might be temporary periods of price stability, we believe that inflation will still continue to be the investor's greatest problem in future years. Our conviction that inflation would increase combined with the acceleration of inflation in the late 1960s stimulated an intensive investment research effort, on our part, to identify those companies with strong natural resource bases -- who own or control large, secure, and low cost tangible assets. Over the longer term and in an environment of a depreciating dollar some of these firms should be able to develop and sell these assets at higher prices. While we still believe that investing in growth companies is a sound investment strategy to offset inflation, we also believe that certain natural resource companies will show well above average investment performance. In the newest Price mutual fund, The Rowe Price New Era Fund, we have, as a matter of policy, placed a large portion of the portfolio in natural resource companies.

Jan 1, 1972