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By William L. Barnes, Maurice Leiser

INTRODUCTION The literature on project management considerations and techniques for large rail rapid transit projects in mid-1979 was fairly large and getting larger. UMTA was establishing special organizational elements to deal with the subject as it related to those properties requesting capital assistance, and comprehensive project management plans were being requested from those properties as an early step to build confidence in UMTA that the particular project could be planned, designed, and executed efficiently and effectively, thereby using critically short capital assistance funds to best advantage. In the late 60's and early 70's, the choices of models for heavy rail construction would have been quite limited.., and perhaps much simpler than was the case in 1979. One of the writers was with an agency in 1979 in the process of finalizing its organization for project implementation after several years of study and had the opportunity to review the experiences of others at length, presumably to build on the success and to try to avoid the pitfalls and failures. The properties that were surveyed all reported more or less success stories. One could only conclude that there are many ways to organize for a major transit (construction) project and that there is a great variety of viable management structures, but it seemed that chances for success were best where the executing property had prepared a comprehensive project management plan, then resolved to follow it. Perhaps more important, a commitment or prior approval had been sought from UMTA as to the validity of the project management plan, and the property was allowed to proceed without detailed prior UMTA review or approval of all specific intermediate steps. Most important, however, an early overall UMTA funding commitment had been obtained that permitted some reasonable expectation of the rate of funding, perhaps by commitment

Jan 1, 1981

By F. Freme

For the second time in four years, the coal industry was brought to the forefront of the nation’s consciousness in 2006, as two separate events unfolded which involved coal miners trapped underground. Unfortunately, the tragic results of the 2006 incidents were not the same as in 2002 when the trapped miners were all successfully rescued. In January, two different incidents, both in West Virginia, focused the public’s attention on the dangers that miners face on a daily basis. As a result of these unfortunate events new legislation requiring improvement in safety in underground mines passed both at the federal and state level. In 2006, a total of 47 miners died on the job, matching the total number that occurred in 1995, and more than double the 22 killed in 2005. Notwithstanding those tragic events, coal production in the United States reached another record level in 2006, ending the year at 1.05 Gt (1,161.4 million st) according to preliminary data from the U.S. Energy Information Administration (Table 1). Production in 2006 was 27.1 Mt (29.9 million st) higher than the prior record set in 2005 of 1.03 Gt (1,131.5 million st). Although coal production rose in 2006, U.S. total coal consumption actually declined for the year. Coal consumption decreased in the electric power sector by 1.1 percent, while coking coal consumption decreased slightly. Only the other industrial sector had higher coal consumption in 2006, increasing by 0.3 percent. (Note: All percentage change calculations are done at the short tons level.) U.S. coal exports declined slightly in 2006, while coal imports again reached a record level. The excess production over consumption allowed total coal stocks to increase significantly during the year, as electric generators rebuilt their stockpiles that had fallen substantially in 2005 because of missed shipments in the second half of that year.

Jan 1, 2007

By C. A. Johnson, K. F. Unrug

The identification of the major subsidence areas in the Eastern Kentucky Coal Field has been made to distinguish the subsidence phenomena on the basis of geographical location. Further, this identification process is based upon selected critical geological, topographical, and mining features in the coal fields. The proposed identification of the regions is derived from a comparison of the subsidence potential in a particular area. The most likely severe subsidence areas are compared to those with the probable low subsidence severity. The combination of certain geological and mining parameters involved allows for the derivation of a classification of the subsidence potential.

Jan 1, 1986

By D. P. Gold

Major sources and reserves of Cb/Nb, Ta, REE, Y, Sc, Zr, Hf, Cu, apatite and vermiculite may be concentrated in primary and secondary minerals associated with different stages and depths of emplacement in carbonatite complexes and kindred alkalic intrusive rocks. Exploration targets include: apatite and pyrochlore (Nb) in the plutonic and hypabyssal core and ring-dikes: bastnaesite (REE), strontianite, barite and fluorite in hydrothermal veins and cone-sheets (subvolcanic setting): thortveitite (Sc,Y) and vermiculite in metasomatized aureoles (fenites): high grade eluvial deposits of apatite and pyrochlore, and secondary REE, Nb, Ti. and V-minerals in supergene and weathered zones.

Jan 1, 1991

By Jeffrey B. Smith

Introduction The gas shortage is going to be with us for some time to come. If we can set aside political and industry rhetoric (along with subjective personal opinions), we still are confronted by two serious "facts of life": (1) for almost a decade the U.S. has been consuming natural gas at a greater rate than we have been finding new reserves; and (2) there is a finite amount of natural gas present within the earth&apos;s crust. Much of the known and easily exploitable sources of gas (the so-called "conventional" sources, such as the high permeability sand reservoirs of the Tertiary sequence along the Gulf Coast) already have been developed; their production is declining rapidly. The total producible reserves from conventional gas reservoirs amount to only 216 Tcf, less than an 11-year supply. However, several large potential resources of natural gas remain to be developed. These "unconventional sources" have low permeability and/or peculiar producing characteristics. The DOE program for development of these unconventional sources of gas is called the enhanced gas recovery (EGR) program. The primary goal of this program is to provide a data base of resource characterization and production technology that will lead to commercial development. DOE will encourage and support industry participation in developing and demonstrating technologies needed to reach this goal. Unconventional Resources Four major unconventional resources of gas have a high potential for commercial development. There are other unconventional sources (such as gas hydrates) that are too poorly defined to warrant a major development thrust at this time. The four unconventional sources of gas currently included in the EGR program are: 1. The carbonaceous shales of Devonian age in the Appalachian, Illinois, and Michigan sedimentary basins are the targets of the Eastern Gas Shales Project (EGSP). 2. The low permeability, low porosity so-called "tight" gas sandstones of the Upper Cretaceous/Lower Tertiary in the Rocky Mountain areas constitute the resource target for the Western Gas Sands Project (WGSP). 3. The free methane trapped in coal beds of both the eastern and western U. S. constitute the Methane from Coal Beds Project (MCBP). 4. The abnormally high pressured, high-temperature saltwater aquifers of the Texas-Louisiana gulf coast are targets of the Geopressured Aquifer Project (GPAP). Basic implementation strategy for these EGR projects involve (1) assessing and characterizing the resource potential of the resource; (2) conducting cost-shared field testing with industry to improve, develop, and demonstrate various stimulation and production technologies; (3) coordinating EGR activities within DOE and with other federal agencies (such as the Bureau of Mines) to minimize duplication; and (4) aiming all projects toward commercial development of the gas resources. EGSP What type of "geological animal" is the EGSP dealing with? While gas undeniably is related to the occurrence of natural fracture systems within the shale, the overall producing mechanism and precise location of fractured, gas-bearing locales within each basin is still poorly understood. By developing reliable resource characterization techniques and applying effective stimulation technologies we intend to elevate the Devonian shale from the status of a potential gas resource to that of a proven gas reserve. Once we have done this the private sector can take over the large-scale commercial development of the Devonian shale gas resource. WGSP The second largest project (both in terms of complexity and level of funding) is the WGSP. The primary targets for this project are the low permeability (< 1 md) gas sandstones of the Piceance, Uintah, and Greater Green River basins and the Northern Great Plains Province. Project success in these four primary geologic locales will permit investigating additional low permeability sandstones in 16 other sedimentary basins. It appears that the only practical means of increasing permeability and resultant flow rates from these sandstones lies in the use of massive hydraulic fracturing techniques. Unfortunately, it is still too early to design such jobs with predictable results. MCBP The MCBP is to be involved in producing and utilizing methane derived from coal beds. The coal, like portions of the Devonian shale, is impermeable, highly fractured (termed "cleat" by

Jan 9, 1980

By Jeffrey B. Smith

Introduction The gas shortage is going to be with us for some time to come. If we can set aside political and industry rhetoric (along with subjective personal opinions), we still are confronted by two serious "facts of life": (1) for almost a decade the U.S. has been con¬suming natural gas at a greater rate than we have been finding new reserves; and (2) there is a finite amount of natural gas present within the earth&apos;s crust. Much of the known and easily exploitable sources of gas (the so-called "conventional" sources, such as the high permeability sand reservoirs of the Tertiary sequence along the Gulf Coast) already have been developed; their production is declining rapidly. The total producible reserves from con¬ventional gas reservoirs amount to only 216 Tcf, less than an 11-year supply. However, several large potential resources of natural gas remain to be developed. These "uncon¬ventional sources" have low permeability and/or peculiar producing characteristics. The DOE program for development of these unconventional sources of gas is called the enhanced gas recovery (EGR) program. The primary goal of this program is to provide a data base of resource characterization and production technology that will lead to commercial development. DOE will encourage and support in¬dustry participation in developing and demonstrating technologies needed to reach this goal. Unconventional Resources Four major unconventional resources of gas have a high potential for commercial development. There are other unconventional sources (such as gas hydrates) that are too poorly defined to warrant a major development thrust at this time. The four unconventional sources of gas currently included in the EGR program are: 1. The carbonaceous shales of Devonian age in the Appalachian, Illinois, and Michigan sedimentary basins are the targets of the Eastern Gas Shales Project (EGSP). 2. The low permeability, low porosity so-called "tight" gas sandstones of the Upper Cretaceous/Lower Tertiary in the Rocky Mountain areas constitute the resource target for the Western Gas Sands Project (WGSP). 3. The free methane trapped in coal beds of both the eastern and western U. S. constitute the Methane from Coal Beds Project (MCBP). 4. The abnormally high pressured, high-temperature saltwater aquifers of the Texas¬Louisiana gulf coast are targets of the Geopressured Aquifer Project (GPAP). Basic implementation strategy for these EGR projects involve (1) assessing and characterizing the resource potential of the resource; (2) conducting cost-shared field testing with industry to improve, develop, and demonstrate various stimulation and production technologies; (3) coordinating EGR activities within DOE and with other federal agencies (such as the Bureau of Mines) to minimize duplication; and (4) aiming all projects toward commercial development of the gas resources. EGSP What type of "geological animal" is the EGSP dealing with? While gas undeniably is related to the occurrence of natural fracture systems within the shale, the overall producing mechanism and precise location of fractured, gas¬bearing locales within each basin is still poorly understood. By developing reliable resource characterization techniques and applying effective stimulation technologies we intend to elevate the Devonian shale from the status of a potential gas resource to that of a proven gas reserve. Once we have done this the private sector can take over the large-scale commercial development of the Devonian shale gas resource. WGSP The second largest project (both in terms of complexity and level of funding) is the WGSP. The primary targets for this project are the low permeability (< 1 md) gas sandstones of the Piceance, Uintah, and Greater Green River basins and the Northern Great Plains Province. Project success in these four primary geologic locales will permit investigating additional low permeability sandstones in 16 other sedimentary basins. It ap¬pears that the only practical means of increasing permeability and resultant flow rates from these sandstones lies in the use of massive hydraulic fracturing techniques. Unfortunately, it is still too early to design such jobs with predictable results. MCBP The MCBP is to be involved in producing and utilizing methane derived from coal beds. The coal, like portions of the Devonian shale, is impermeable, highly fractured (termed "cleat" by

Jan 1, 1980

By J. P. H. Steele, T. Vincent, C. Debrunner, M. Whitehorn

For a variety of reasons, the need for automation of underground mining equipment is growing dramatically, e.g., improved safety and health, availability of labor, deeper mines, and desire for more focused excavation. While there has been tremendous progress made in this direction, much needs to be done to reach the holy grail of an autonomous mining machine. This paper reviews a number of technological developments and presents research and development needs for future development. A report on our current project for the Western Mining Resource Center at CSM is included.

Jan 1, 2000

By A. John R. Hart

INTRODUCTION In each given set of operational criteria for tunnel design, ground conditions dictate the selection of the most appropriate construction method and tunnel lining. The designer has the responsibility to choose or restrict the choice of the tunnel lining to insure that the final solution provides a cost-effective permanent construction which will require the minimum of maintenance and endure to the benefit of future generations. This Paper deals with some of the aspects of precast concrete tunnel linings, their history and development through the years. It does not purport to be a comprehensive review of all that has ever been tried or developed but, hopefully, a starting point to encourage discussion and development for the future. BOLTED LINERS As a result of anticipating a shortage of cast iron tunnel lining in 1936 when work was proceeding on London Transport&apos;s Central Line Metro, a design for the precast reinforced concrete bolted lining was born. The design took the form of the traditional cast-iron lining but with substantial concrete stiffeners to take the shield ram forces. This new lining was used to construct some 14,000 feet of running tunnel using a ring width of 1&apos;8" which was the standard cast-iron width of the time. (Groves, G.L., 1943)

Jan 1, 1987

By P. C. Kapur

For mineral processing spirals, mathematical force equilibrium models are sought to extend the spiral performance envelop. In Part 1 of this report, a complete geometric description of the helical spiral and its trough or channel contour is provided. The secondary circulatory fluid motion in the transverse direction that develops when water flows down a tightly turning curvilinear path and its implications for gravity separation are discussed. Different forces that act on the particle during its passage through the spiral are enumerated and quantified for a better appreciation of their relative contributions and roles in the separation process. Three force equilibrium models from the hydrology literature on sed iment transport are employed to simulate a typical spiral. While the results are promising in that the models mimic the broad performance characteristics of the spiral, what is needed is a more general spiral model taking explicit cognizance of the missing components essential to the spiral description. These are such components as centrifugal force and the steep tangential slope of the channel deck. Results of this latter exercise are deferred to Part 2.

Jan 1, 1996

By Theodore Feldsher, Seung Han Kim, Mourad Attalla, John Roadifer, Chu-Chieh Jay Lin

Lifelines in seismic regions of the world seldom can escape crossing active faults. Cities in California have been mitigating this risk by constructing improved fault crossings. This paper discusses the analyses and design of the lining for a tunnel carrying a water conveyance pipeline through a fault that can potentially displace during a major earthquake event. The paper presents expected fault displacement, fault width and orientation respective to the tunnel, characterization of the ground surrounding the tunnel and its interaction with the lining, and performance required of the lining. Several other fault crossings will also be presented and discussed

Dec 1, 2022

By Wallace W. Roepke, Richard C. Olson

To adequately attack the longwall dust problem, the US Bureau of Mines funded a contract to define dust sources on a longwall mine face area. The study examined the shearer during sumping, cutting, and tramming, the conveyor, and the roof supports. Tests showed the shearer to be the major dust source. Introduction Long-term illnesses place a heavy burden on miners, the mining industry, and taxpayers. Black lung payments to more than 400,000 miners and their survivors exceeded $9 billion between 1970 and 1980. They are continuing at a rate of $1 billion per year. Recent MSHA data indicate more than 50% of the longwall faces are still out of compliance with the 2 mg/m3 (0.00007 oz per cu ft) respirable dust regulation. Allowable dust limits are often further reduced owing to the presence of silica dust. This substantially increases the problem&apos;s severity. Research in the 1970s showed that by modifying the mining method through changing drum-type mining machines from high rpm shallow cutting to slow rpm deep cutting, both specific dust and energy could be reduced (Black et al., 1978; Ludlow and Wilson, 1982; Roepke, Lindroth, and Myren, 1976). The coal mining industry is using more longwall equipment to economically obtain high productivity. This high production rate, however, makes it difficult for longwalls to meet the legal dust standard. Research is showing how both these concerns may be addressed at the mining face. Results reported here explain the relationship of various major elements of the longwall system to dust generation on the longwall face. This paper is based on work completed by Foster-Miller Associates Inc. Objectives were to differentiate dust sources on the longwall face and to quantify dust levels for various elements of the shearer drum. The work was accomplished in two phases. Jonathon Ludlow, project engineer for FMA, developed and performed the necessary testing (Ludlow and Marshall, 1983). Bradley, Hadden, and Weston (1983) have done evaluations on British coal mines that produced similar results to those reported here. They found causative rela¬tionships between haulage speed, production, depth cut, drum speed, and dust generation. They also found that roof support movement increased the dustiness, whereas this work indicated that support movement had only a minor effect on total dust exposure. Both of these results are valid when the variation of mining conditions is analyzed. British mines are deeper than US mines. Therefore, roof rocks and coal are more fragmented than in the shallower US mines. Other reasons for the dust differences include the weaker shales found in Britain and the variation of roof support equipment designs between the UK and the US. Four mines in this report had rock roofs and, thus, would be less dusty. The fifth longwall mine had a coal roof, but the large cross-sectional area and high air velocity minimized dust exposure. Mines and Equipment Five underground longwall mine sites were tested (Fig. 1). All were using double-ended ranging-drum shearers (derds) with some variations in equipment. The mines and equipment details are shown in Table 1. No modification of mining equipment or operating cycles was made during the first phase of testing. The mining process observed followed the normal mine operating procedures. Three GCA RAM-1 respirable dust monitors and two vortex anemometers with cycle notations on portable tape recorders were used in each face area. The start and end of each cycle segment were recorded. Dust monitors record the dust levels once every 10 seconds, thus providing a relatively continuous real time indication of change in

Jan 8, 1984

By J. C. Stankus

How to quantitatively identify the loads on a square/arch set is a complicated issue in designing the square/arch set in an intersection/entry. From an engineering perspective, understanding the nature and support mechanism of standing support such as a square/arch set can not only help design the support structure to maintain the roof stability, but save the steel materials and costs of manufacturing, labor, and delivery. Based on the design practices in recent years and successful applications in slope bottom intersections, the authors are confident that the concept of interaction and confinement effect between the steel square/arch set and surrounding rocks is critical in designing a proper steel structure to support an intersection/entry. This paper will detail the design concept and its applications in several underground slope bottom intersection designs, reaching the goals of improving roof stability and reducing costs.

Feb 23, 2014

By Andrew S. Lain

Before you begin mining aggregates in Oklahoma, you must first look at the market and ask these questions: (1) Is there a need for additional aggregate production? (2) Can we produce the aggregate efficiently enough to compete? (3) Is the deposit close enough to the market? If you can answer "yes" to each of these three questions, then you are ready to start the process for mining aggregates in Oklahoma. The first consideration to be made is whether the aggregates produced will need to meet state specifications. If you do not want to meet state durability standards, there are numerous formations you can mine and produce aggregates. We will deal only with the formations that will meet state durability standards. These formations are located in the southern half of Oklahoma and in the Tulsa area. Some of the formations that contain limestone, dolomite, and sandstone that will meet state durability tests are West Springs Creek, Kindblade, McKenzie Hill, Butterly-Royer, and Rush Springs Formations. Granite and rhyolite also are found in Oklahoma and can be used as construction aggregates. Once an area has been identified as having durable material, and drilling has verified its properties, a permit must be secured from the Oklahoma Department of Mines, Oklahoma Department of Environmental Quality, and any other applicable agency before construction of a plant occurs. There are many different brands of crushers available, but all work on one of two crushing principles-either compression breakage or impact breakage. Each type has its application in different industrial-mineral types and the desired end product. A typical small crushing plant would start with a jaw crusher for primary reduction, and then employ one standard cone and one shorthead cone for secondary reduction. One grizzly would be in the circuit with one finished-product screen and three to four finished-product stackers. Natural sands and gravels are found in rivers and old river channels. These too need to be tested to see if spec product can be produced. All of our sand operations have very little gravel; thus, we do not process the gravel. The sand is processed through classifying tanks for gradation.

Jan 1, 1999

By John Mitchell, Mark K. Jorgensen

Newmont Mining’s Ahafo Mine is located in Ghana approximately 300 km (190 miles) northwest of the capital city of Accra in the Brong-Ahafo region. The nearest city is Sunyani, located 45 km (28 miles) to the north. The Ahafo Mine will process ore from seven major pits that extend along a 40-km (25-mile) strike. Four pits are in the south and three pits are in the north. The resource is currently stated at 373 t (12 million oz). But it still has the potential for growth both from new discoveries and the development of underground operations.

Jan 1, 2007

By B. Alegria

The depressing effects of different inorganic chemicals on the flotation of pyrite have been investigated in this study. The results of the flotation tests indicate that pyrite can be depressed by oxidizing as well as reducing agents under controlled conditions of pH and reagent dosage. Oxidizing reagents such as potassium chromate and potassium dichromate were found to cause complete depression of pyrite in the acidic pH range. These effects are similar to those obtained in the pyrite-cyanide system. A less stable oxidant, potassium permanganate, inhibited the flotation of pyrite at a concentration as low as 0.1 mol/L at all pH values, Addition of reducing chemicals such as ferrous chloride or manganous sulphate to the flotation of pyrite were found to produce depressing effects depending on the additive concentration and pH of the solution.

Jan 1, 1982

Several industrial-scale HydroFloat separators have recently been installed at Mosaic?s South Fort Meade beneficiation plant for the purpose of improving phosphate recovery and throughput capacity. This technology was implemented after numerous laboratory, bench-scale and on-site, pilot-scale test campaigns. The results from this detailed test work provided sufficient justification for the complete retrofit of the existing coarse and ultra-coarse flotation cells. Data indicate that the metallurgical results obtained with the full-scale separators are consistent with that obtained during both the bench- and pilot-scale evaluations. The benefits, theory of operation and commissioning of the equipment are also discussed.

Jan 1, 2007

In June, 1,334 underground construction and tunneling professionals gathered in Toronto, Ontario for the 2007 Rapid Excavation and Tunneling Conference (RETC). This biennial event, sponsored by SME, is one of the global underground construction industry?s major events. And this year?s RETC was the first one that included the new Underground Construction Association. [ ] (UCA) of SME. In addition, the conference?s exhibit attracted 125 equipment and service providers. The next Rapid Excavation and Tunneling Conference is set for June 14-17, 2009 at Caesar?s Palace, Las Vegas, NV.

Jan 1, 2007

By Patrick Oriez, Chris Norris, Alain Mercusot

"Temporary mechanical ventilation is one of the fundamental requirements in guaranteeing a healthy atmosphere in underground construction works in order to protect the health of persons working on the site. It is therefore essential to conceive a system which meets the requirements of the whole of the worksite and for all phases of work which takes into account all aspects pertaining to its design, dimensioning, justification, installation, maintenance and validation. In doing so, the ventilation design and the selected apparatus to be installed shall meet with the degree of health protection and the quality of air of the worksite as defined by the legislation in force in France, through limiting the concentration of the different pollutants associated with the site activities. Consequently, when presenting a mechanical ventilation project, all of the participating parties and especially the contractor make a commitment to guarantee sufficient volumes (or airflow rates) of fresh (non-polluted and oxygenated) air and extracted (polluted) air in order to meet these limitations and maintain them in all conceivable site configurations. This article sets out the most important aspects of the implementation of a ventilation project from the initial design stage through to its application, discussing French legislation, ventilation principles, calculations and techniques with regards to underground construction sites. BASICS OF VENTILATION Mechanical ventilation studies are concerned with all of the site workstations and work phases which are sources of pollution and apply to all zones of the underground worksite with the goal of maintaining the concentration or composition of this pollution below the permitted levels and comply with the following three basic principles which are complementary to one another without being in contradiction. •,The first principle consists in eliminating or limiting as much as possible the emission of any polluting, irritant, or dangerous substances, by specifying appropriate construction techniques and equipment (use of electric motors, combustion engine equipment: filters, tanks, catalyzers, use of less polluting explosives, damping down dust with water or wetting products, damping down and diluting certain gases using water mists). •,The second principle is designed to capture residual polluting substances emitted close to the source in order to prevent them from spreading into the worksite atmosphere (extraction ventilation with ducting up to the source – upstream of the extractor fan – and use of downstream filters before expelling the polluted air to the exterior). •,The third principle involves accompanying the capture of the pollutants with additional blowing ventilation specific treatment of substances dissipated by and distant from the source of pollution (acceleration of the drift air flow in order to confine dust and better capture it, supply ventilation with ducting in order to dilute the gases emitted and discharge them to the exterior)."

Jan 1, 2016

By J. Ke

Traditional geostatistical methods have been used in ore reserve estimation for decades. Neural Networks (NNs) have provided an alternative approach to data analysis and ore reserve estimation. Unlike the traditional geostatistical methods, neural network uses a highly non-linear complex algorithm to do the estimation. Although Neural Networks have been demonstrated to be attractive alternatives as with every new techniques, there are questions which remain unanswered. This paper presents a comparative analysis with different types of metamodeling approaches -- Triangular, Kriging, Spline, and Neural Network. The neural-network is organized in a multiple-layers and Back-propagation model is used to handle the non-linearity and hidden slabs for smoothing the predicted results. With multiple dimensional and very noisy drill hole sample data, the ore grade is predicted and the overall performance is validated by the analysis of R-squared (R2), Root-Mean-Squared (RMS), and contours of ore grade spatial variability. The ore grade and tonnage of estimated outputs are also compared with various cut-off grades.

Jan 1, 2003

By George M. Leonard

Mineral commodities on National Forest System lands contribute to the nation&apos;s well being. Access to these commodities is dependent on public perceptions of the effects of mineral operations on other resources. An outlook is described which the Forest Service believes is essential to the minerals industry if it plans to continue seeking minerals on National Forest and Grasslands.

Jan 1, 1991