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By S Hapugoda, J Manuel, E Donskoi, L Lu

Sinter can constitute up to 80–85 per cent of the total ferrous burden in modern blast furnace ironmaking operations. The mineralogy and microstructure of iron ore sinter play an important role in determining its physical and metallurgical properties. As a result, characterisation of sinter phases is a cost-effective and complementary tool to conventional physical and metallurgical testing of iron ore sinter in evaluating and predicting sinter quality. Over the years, CSIRO has developed a scheme for characterising iron ore sinter that classifies primary sinter phases such as unreacted and partially reacted hematite and magnetite, and secondary phases, including prismatic high-temperature silico-ferrite of calcium and alumina (SFCA), microplaty SFCA (SFCA 1), dense SFCA, secondary hematite and magnetite, glass, larnite (dicalcium silicate; Ca2SiO4) and remnant fluxes. Quantification of these phases has traditionally been carried out by manual point counting under a petrographic microscope; however, new technologies based on automated optical image analysis, quantitative X-ray diffraction and scanning electron microscopy are now available for evaluation. In this study, two sinter samples of varying chemistry were prepared and characterised using both point counting and automated optical image analysis. The implication of the results obtained for the performance of different quantification methods is also assessed.CITATION:Hapugoda, S, Lu, L, Donskoi, E and Manuel, J, 2015. Mineralogical quantification of iron ore sinter, in Proceedings Iron Ore 2015, pp 35–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

During the period 1981 - 1991, Esso Australia and their Joint Venture partners have discovered about 180 MB of liquids (crude and condensate), 60 MB natural gas liquids and 800 - 1000 GCF of gas. A total of 48 wildcat wells were drilled including 12 new pool discoveries drilled from platform facilities. Significant discoveries include the West Tuna, Kipper, Blackback and Terakihi fields. These four discoveries, contribute to 75 per cent of the total reserves discovered in the last decade and were all high-risk plays. The Kipper discovery, in the pre-Latrobe Golden Beach Group top sealed by volcanics, and the Blackback-Terakihi discoveries, located on the present day continental slope in water depths ranging from 300-700 metres are both the result of successful drilling outside the traditional exploration bounds for the basin. During the last decade, Esso and its partners have spent about A$400M on wildcat exploration activity. The exploration success rate, excluding platform based drilling, has been 50 per cent for wildcat wells. On a technical front, the last decade has heralded substantial improvements in seismic data quality. Peak frequency content in seismic data at the Latrobe Group target levels is now double that of the early 1980s. Significant advances have also been made in our understanding of sequence stratigraphy, geochemistry and geohistory of the basin.

Jan 1, 1992

By E A. Agorhom, M Beyuo, C Owusu, I Quaicoe

Understanding the mineralogy and liberation of gold particles in an ore is key to the development and optimisation of gold processing operations, being cyanidation or gravity separation. This can be achieved through basic historic geological information, gold deportment studies, chemical speciation and metallurgical test works. The present study assessed the nature of the occurrence of gold particles (mineralogical composition, liberation, associations and surface chemistry) and its effect on the process route (cyanidation and gravity separation) of a typical paleo placer gold ore deposit within the Tarkwaian Rock system. The investigative approach used involved chemical assay, quantitative X-ray diffraction (QXRD) and quantitative evaluation of minerals using scanning electron microscopy (QEMSCAN). The ore samples (A, B, C, D, E, F) used were obtained from six active pits of a gold mine working on this orebody. The results of the mineralogical analysis revealed that the ore is highly oxidised and comprised quartz (>80 per cent) and Muscovite mica (>6 per cent) as the major mineral phases in all the samples. Trace amounts of hematite, kaolinite and todorokite were also identified in all the samples. The chemical analysis showed presence of gold (Au) in all the samples with samples B (3.62 g/t) and C (3.96 g/t) containing the highest concentrations. Trace amounts of copper (Cu), iron (Fe), sulfur (S), aluminium (Al), arsenic (As) were also detected in all the ores. The QEMSCAN mineralogical liberation and gold association results revealed that the gold grains were relatively coarser in all samples (P80 > 80 µm Au in size) except F (P80 < 32 µm Au in size). Gold grains were highly liberated especially in sample B with the majority of the locked gold grains forming complex associations. All the samples responded well to cyanidation and gravity separation except samples C and F, respectively.

Aug 24, 2022

By K B. Quast

During the prefeasibility stage of the mining cycle for a gold deposit, an evaluation of the ore leaching characteristics from various defined areas is essential prior to plant design. There are a number of simple laboratory tests which have proven successful in establishing gold and silver leaching kinetics, carbon adsorption and fouling, as well as elution characteristics. A number of case studies of carbon-in-pulp (CIP) simulation are presented which show excellent agreement between calculated and assayed gold and silver grades in feed and adsorbed on carbon which validate the methods used.

Jan 1, 1998

By J J. Eksteen

"In the platinum group metals (PGM) industry, smelters are often perceived as ‘black boxes’ that have to process concentrates of variable mineralogy and originating from multiple mines operating along strike or downdip from each other in the same geographical region, as is the case in the Western Bushveld of South Africa. However, PGM smelter complexes are much more sensitive to concentrate blend variation than most metallurgists or geologists would anticipate.This paper will review the impact of concentrate blends deriving from a number of concentrators processing ores from the Bushveld Igneous Complex (BIC) on smelting and converting behaviour and the constraints they impose upon smelter operation. Significant variation in behaviour is not only noted between the main mineralisation types, namely the Merensky and Upper Group 2 (UG2) reefs, but also within a given reef type. Due to the way PGMs are mineralised and finely disseminated, concentrators have to grind concentrates ultra-fine to liberate the PGMs and provide a sufficiently high-grade concentrate for smelting.The chemistry and mineralogy of the concentrates vary with the type of mine (open pit versus underground), the reef type and varies along strike; this variation impacts numerous key smelter parameters such as the base metals content, the matte fall, the converter aisle capacity, sulfur dioxide gas production, furnace matte and slag temperatures, and the accumulation of high smelting chromite-spinel minerals that has led to significant smelter upset conditions such as catastrophic furnace hearth and sidewall failures.Due to the production intensity of smelting, ie its high rate of processing per unit volume, smelters have been found to be far more sensitive to rapid variation in concentrate properties, highlighting the need for adequate blend control.CITATION:Eksteen, J J, 2016. Impact of Mineralogical Variation on the Smelting of Cu-Ni-PGM Concentrates, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 321–326 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

MIM Holdings Limited (MIM) committed to a long-term future in copper in the Carpentaria Mineral Province in 1996 with the development of the Enterprise and Ernest Henry mines, and an upgrade of MIMsÆ copper smelter in Mount Isa, and copper refinery in Townsville. The upgrade of the copper smelter will enable the smelter to produce 250 000 tpa of copper with a single primary smelting unit, the copper Isasmelt furnace installed in 1992. The copper Isasmelt furnace currently smelts concentrate containing 145 000 tpa copper. To reduce the risk associated with the copper smelter upgrade, and shorten the ramp up time of the upgraded smelter, two high-rate trials were undertaken in 1997 to demonstrate that the copper Isasmelt furnace could, with an additional 525 tpd of tonnage oxygen, treat concentrates containing 250 000 tpa copper. During the trials the concentrate feed rate to the Isasmelt furnace was increased from its average rate of 100 tph of concentrate to 150 tph of concentrate. The increase in the capacity of the furnace was achieved by: supplementing the installed tonnage oxygen capacity of 595 tpd with an additional 300 tpd supply; reducing variability in the furnace feed rate from ¦25 per cent to less than ¦5 per cent; and reducing tramp air. The Isasmelt furnace smelted concentrate at a rate of 140 to 150 tph for four hours 25 minutes during Trial 1, and at a rate of 150 tph of concentrate for five hours and 30 minutes during Trial 2. The oxygen utilisation was 100 per cent during the trials with the process remaining under control. As a result of the development work for the trials the average treatment rate of the furnace under normal conditions increased by ten per cent.

Jan 1, 1998

By D Hunter

A production information management system (PIMS) was recently implemented at Queensland NickelÆs Yabulu Refinery. Although a strong business case was developed to justify the significant investment in PIMS some potential beneficiaries remained sceptical of the anticipated benefits. The decision to install PIMS was justified as the on-line availability of continuous production data enabled the optimisation of some crucial operations resulting in significant cost savings, improved throughput and final product quality. Furthermore the rapid access to extended historical data has allowed the cause of repeated failure of equipment to be determined. The investment is expected to pay for itself within two years and has already contributed towards significant savings. This paper focuses on some of the diverse production improvements gained and compares the anticipated benefits in the business case to those achieved. A brief outline of the phased implementation of the OSIsoft PI data historian and complementary client software at Yabulu is included, along with details of the lessons learned.

Jan 1, 2003

By M D. Urbani

HiTec Energy Ltd has been conducting research since 1996 into novel process routes for the treatment of low-grade and waste manganese sources for the production of high value and high quality electrolytic manganese dioxide (EMD) for the alkaline battery market. HiTecÆs approach is to treat previously unsaleable manganese deposits and mine site tailings using a novel sulfur dioxide leach route, followed by purification and electrowinning to generate the sought-after EMD product by an environmentally superior processing route to those presently practiced throughout the world today.HiTec Energy Ltd expects to be in commercial production with its Stage 1 facility in Kalgoorlie in the last quarter of 2004 for the production of 12 500 tpa EMD. With this production facility being adjacent to a laterite nickel producer with available waste manganese units, the opportunity arose for HiTec to combine its existing technologies with processes (that will be discussed in this paper) to turn two waste by-products into products that are used for high-tech purposes.HiTec Energy Ltd and the Parker Centre have had a collaborative research relationship for a number of years in areas involving EMD and battery related technologies. Meanwhile the solvent extraction (SX) group of the Parker Centre (CSIRO Minerals) has developed SX processes to separate manganese from nickel and cobalt. A project was initiated by HiTec Energy to recover manganese from waste laterite leach solutions using SX technology. Batch tests were conducted to select a suitable organic system for the extraction of manganese in terms of selectivity and extraction and stripping kinetics.A total of eight organic systems were tested by determining pH isotherms of metals using a laterite nickel process waste stream. Two organic systems, the Versatic 10 and Versatic 10/synergist systems, were chosen for further test work with Shellsol D70 chosen as the diluent for both systems.The Versatic 10/synergist system would be advantageous over the pure Versatic 10 system because fewer SX stages are required, resulting in a smaller organic inventory and lower capital costs. The risk of gypsum formation is also significantly lower with the synergistic system.

Jan 1, 2004

By Kwitko G

Exploration for coal has been on-going in South Australia for the past 100 years. During this period substantial resources of low rank coal have been delineated throughout the State. These deposits are of variable quality often with high moisture, sodium, chlorine, sulphur and ash content and although generally regarded as suitable for use in conventional pulverised fuel boilers, many are difficult to utilise. The only operating coal mine in South Australia is at Leigh Creek where coal bearing shale was discovered by chance in 1888 during excavation of a railway dam near the township of Copley. Leigh Creek has had a very diverse mining history from the initial small scale underground mining through to open-cut mining utilising draglines and more recently large shovels and trucks.

Jan 1, 1992

By L Keeney

Geometallurgy is not a mechanism designed to replace current geological and metallurgical deposit characterisation but an added component required to understand orebody variability. Current geological characterisation approaches focus on understanding deposit genesis aimed at identifying new mineralised regions and metallurgical characterisation determines parameters required for engineering design of processing plants. Geometallurgical integration has the task of drawing on aspects of each stream to enable spatial mapping of performance indices across a deposit. It is a complimentary activity to current practice and adds a new dimension to orebody knowledge. Although the notion of conducting an integrated geological and metallurgical analysis is not a new concept, limited publications exist in the field proposing integrated methods, with several technical issues existing in current geometallurgical integration approaches. An iterative method drawing on existing geological and metallurgical characterisation and new measurement tools and inputs is proposed. The integrated method comprises of discrete components dynamically linked together through iterative feedback loops with each component having a specific purpose achieved by applying a range of data acquisition technologies and statistical tests. The key outcomes of the method are:overcoming the lack of optimised geometallurgical domains relevant to processing performance,development of a rigorous approach to identifying parameters controlling processability,improved protocols for relevant metallurgical test data and sample selection, andability to generate greater data support to enable rigorous geostatistical modelling of geometallurgical attributes. This paper outlines the integrated mapping and modelling method developed and draws on multiple data acquisition technologies applied within the AMIRA P843 GeMIII Project.

Sep 5, 2011

By R G. Reddy

The complexity in treating environmentally harmful impurities such as As, Sb, Bi from the base metal matte or metal in the smelting stage are responsible for the high cost of the refining process. The impurity capacities (such as arsenic, antimony and bismuth) of slags were calculated a priori using Reddy-Blander (RB) model. The capacity predictions were for a wide range of matte and slag compositions in copper smelting conditions. The calculated impurities capacities and impurity distribution ratios results are in good agreement with the available experimental and industrial slags data. The a priori knowledge of impurities is useful for reduction of energy consumption and enhanced environmental control in the current and future non-ferrous metal processes.

Aug 21, 2024

By J M. F Clout

The low-grade clay-rich -1.0 mm fraction of fine iron ores have often proved difficult to upgrade and capital intensive to process when using traditional wet beneficiation technology including single or two stage hydrocyclone desliming, wet high intensity magnetic separation (WHIMS), spirals and final dewatering using fine screens. Very fine (&lt;0.010 mm) clay-rich slimes simply follow the water split to the hydrocyclone underflow where it often impedes the subsequent processing performance of any downstream spirals and can result in troublesome direct dewatering of hydrocyclone underflow. The -1.0 mm fraction in goethitic iron ores is typically considered as waste. A new two-stage wet gravity separation flow sheet, referred to as the ædesandÆ process, has been designed to overcome these issues for the upgrading of low-grade clay-rich goethitic or hematite-quartz fine iron ores. The desand process is designed to treat the -1.0 mm range from -8.0 mm natural fines, to recover a -1.0 +0.038 mm higher-grade fraction by rejecting to tailings any low-grade clay-rich ultrafines and low density sand-size fine chert/quartz gangue and shale.The desand process consists of wet screens with a nominal 0.7-1.0 mm cut point which direct the undersize to hydrocyclones. The hydrocyclone underflow is then fed to upcurrent classifiers where the classifier middlings is sent to spirals and classifier and spirals concentrates are then dewatered using vacuum belt filters or fine screens. The three product upcurrent classifier is employed to further deslime the hydrocyclone underflow, producing firstly a coarse final concentrate, and then a deslimed middlings for feeding to spirals as well as a 0.100 mm clay and fine quartz or banded iron formation (BIF) sand in final overflow for feeding to the residue thickener. The upcurrent classifier middlings provides the spirals with a significantly cleaner feed material than traditional methods, with the end result that the spirals do not silt up with slimes and therefore can continue to run at their optimum. The upcurrent classifier and spirals form a complimentary pair, with the upcurrent classifier better able to send coarser, acceptable grade particles to concentrate and fine slimes to tailings whilst allowing the spiral to better reject coarser, subgrade low specific gravity particles. Test results for the Mayoko-Moussondji iron project, Republic of Congo, using upcurrent classifier-Wilfley Table (simulating spirals) gave acceptable mass recovery from run-of-mine (ROM) and Fe recovery from hydrocyclone underflow for HEMCOL (6.2 per cent mass recovery from ROM/43.1 per cent Fe recovery) and HEMBIF2 (5.1 per cent mass recovery from ROM/22.3 per cent Fe recovery) mineralisation types. The desand process also enables improved dewatering of -1.0 +0.038 mm product from a clay-rich plant feed.A number of new wet plants in the Pilbara use the desand flow sheet including FMGÆs Cloudbreak and their two Christmas Creek plants. Many potential new applications are being explored, with new iron ore plants in India as well as those being proposed for West Africa. Operational experience has highlighted the importance of providing clean process water to the upcurrent classifiers as well as ongoing design improvements including increased wear life, reduced maintenance and enabling a more steady feed rate to spirals.CITATION:Clout, J M F, 2013. Beneficiation of fine iron ores using the desand process, in Proceedings Iron Ore 2013 , pp 337-348 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By R C. Schodde

The future of any mining company depends on maintaining and growing its access to high-quality mineral resources. Often the true size of a given resource is not fully recognised until after mining has commenced. Also, the strong desire to increase production puts pressure to expand the resource base of the mine to get maximum value out of the capital employed. This, plus diminishing M&amp;A opportunities and declining world-class greenfield discovery rates, makes brownfields exploration a high priority activity in any operating company. For the success and long-term survival of the company it is critical that this is done well. The primary aim of brownfields exploration is to find or acquire new deposits within economic transport distance of an existing mine that will add materially to shareholder value through: mine or capacity expansion, displacement of lower-margin ore from the mine plan, preserving and extending the mine life, and ensuring potential value is understood in order to maximise potential future mine development or exit. A number of strategic principles are important in any program designed to achieve these aims: understanding the life of mine (LOM) production profile and the related key drivers for exploration, understanding the dynamic nature of the brownfields search space, understanding and measuring depletion of the brownfields search space, understanding the potential of the near-mine region, investing in exploration technology to expand the search space, and investing in a basic geological understanding of the ore-environment. Examination of the LOM profile will highlight critical issues facing development plans for the mine including future grade and throughput issues, key technology requirements or innovations and scenarios for increased production. Exploration targets in the brownfields program should address these key issues. Often it is as æsimpleÆ as keeping mine development sufficiently far ahead of extraction to allow time for the various phases of exploration and resource assessment drilling. Because of the low additional capital costs required, expansion of the brownfields search space is strongly leveraged to: metal prices, development of new markets, incremental operating cost reductions, strategic changes in downstream requirements in integrated businesses, depletion of higher unit-value ores, and new technologies (both extraction and exploration). Therefore the brownfields search space is likely to incrementally expand through time and must be regularly reviewed. This is also important as any given search space will be progressively exhausted, resulting in smaller and higher cost discoveries. It is therefore important to monitor and critically review sustained trends of increasing brownfields discovery cost. The first wave of discoveries in any camp are usually empirically driven and do not need a strong geological understanding. However, an improved geological understanding is critical to making the next generation of hidden discoveries. To illustrate these points, a case study was carried out on the exploration and development history of the Kambalda nickel camp. Over a period of 40 years, more than 40 deposits were found containing over 1.7 million tonnes of nickel metal. Efficient mines need to maintain reserves for operating flexibility. Consequently, the company needs to clearly understand the global resource in order to maximise its full potential. In addition, understanding the full brownfields potential earlier in the development of a deposit rather than later, creates optionality through the flexibility that this understanding brings to future development choices. To ensure best practice in attaining this aim, the roles and responsibilities of the exploration team and the mine operation should be clearly understood. It is important for the explorers and the operators to have shared views about what needs to be done. Typically, mine operators would be accountable for identifying future resource requirements to support the life-of-mine production schedule whilst explorers would be accountable to ensure best-practice assessment of brownfields exploration opportunities. This would include an assessment of the global undiscovered endowment in the regional near-mine area. The balance between brownfield exploration drilling and resources to reserve conversion will need to be decided to ensure efficient operations are maintained. Both need to agree the optimum level of brownfields funding taking into account: urgency to replace or grow reserves, and quality of opportunities (relative to those elsewhere). The ultimate cost of ignoring the full brownfields potential of an operating asset can be significant, ranging from inefficient and poorly planned operations, lost opportunity cost and resultant value through under-utilised resources and, in the worst case, early exit from the asset at the bottom of the commodity cycle û leaving behind huge amounts of shareholder value.

Jan 1, 2006

By B Clements, R Dunne, J Dioses, S Hart

In April 2003 plant upgrades in the æLow GradeÆ Cadia Hill circuit were undertaken in order to improve concentrate quality and metal recoveries from the flotation circuit. The major changes involved: circuit reconfiguration to allow all concentrates to be reground to less than 38 ¦m prior to final cleaning; increasing ball charge in the regrind mill to fully utilise all of the installed power; desliming of the cleaner scavenger concentrate to improve the circuit water balance; and the inclusion of a gravity concentrator in the regrind circuit to recover more free gold to bullion.Once the flotation circuit had stabilised under the new operating conditions concentrate launder modifications and increased froth crowding on the scavenger flotation cells permitted the introduction of stronger collectors without compromising concentrate quality or circuit stability.Twelve months on, the copper concentrate grade has increased by two per cent and metal recoveries increased by three per cent and seven per cent for copper and gold respectively. The project capital outlay of approximately $2.0 million has been repaid in less than three months. This paper will review the project from the design, construction and commissioning perspective as well as the subsequent debottlenecking exercise that was required to eventually yield the full benefits of this upgrade.

Jan 1, 2005

The optimal production of the metals needed by society is best achieved by a close synergy between concentrate production and smelting. For over 75 years commencing in 1923, such a close relationship was enjoyed between the Sullivan Mine in Kimberley, British Columbia and the Trail zinc-lead complex. An effective program of continual change and improvement at the Sullivan concentrator was achieved through a strong entrepreneurial spirit. This spirit was in part maintained through a favourable location in south-eastern British Columbia that resulted in a dynamic local community that has survived the closure of the mine. Innovations to be reviewed include feed forward reagent control, the use of column flotation to zinc and lead cleaning and the application of ultrafine grinding coupled with concentrate dewatering using hyperbaric filter technology.

Jan 1, 2005

By J A. Cowburn

The high intensity zone within the Jameson Cell is the downcomer. It is largely external and separated from the flotation tank. This, together with operation of the downcomer under vacuum, rather than at elevated pressure and the absence of moving parts, allows ready access to the high intensity zone for measurement and analysis. Experimentation was conducted allowing measurements of recovery for residence times of between 20 milliseconds and ten seconds within the downcomer of a Jameson Cell. The affect of aeration rate on the recovery of different particle sizes was also studied.

Jan 1, 2005

By J S. J van Deventer, D C. Shallcross

New developments are taking place in the recovery of gold from leached pulps that are based upon the adsorption of the metal cyanide species onto ion exchange resins. Despite the success of several resin-in-pulp pilot plant operations in the Western World and large-scale plants in the former Soviet Union, the process is yet to gain recognition as a viable alternative to the carbon-in-pulp process. An experimental research program has investigated the use of a variety of different types of resins for the recovery of gold, but to-date no resin studied has the desired properties of high selective loading capacity for gold cyanide and a simple inexpensive elution procedure. In addition very little is known concerning the physical strength of resins and their ability to resist shattering due to osmotic shock during cycles of adsorption and elution. The ability of ion exchange resins to enhance the leaching of refractory and re-adsorbing ores has not been investigated. This paper highlights the necessary factors that need to be addressed before commercialisation of ion exchange technology for gold extraction is feasible.

Jan 1, 1998

By V Gupta, Z Huang, S K. Biswal

G-Cell is a new design modification of the Imhoflot pneumatic flotation technology, which utilises a self-inducing aerator inside a downcomer, where bubble-particle attachment takes place. The present study has investigated the suitability of the G-Cell technology for cleaning fine coal using a 0.8 m diameter prototype unit at a coal preparation plant operating in the Midwestern United States. A slip-stream obtained from the overflow of raw coal cyclones operating in the plant, containing nominally minus 150 micron size particles and having ash content in the range of 40 per cent to 50 per cent and sulfur content in the range of 1.30 per cent to 1.50 per cent, has been used as the feed for the G-Cell. The performance data produced from the G-Cell tests are found to be very close to the ideal performance curves produced from release analysis. A statistically designed experimental program has been conducted to investigate the parametric effects on various key process responses, such as combustible recovery, product ash and sulfur rejection. The empirical models developed in this study have been utilised to identify a suitable experimental region for achieving a desired combination of response targets.

Jan 1, 2005

By Holmes RJ, Sowerby BD, Watt JS

Major improvements have taken place in mineral and coal processing in the last decade. The development of nuclear on-line sensors that continuously analyse the material being processed has led to better control of metalliferous mineral processing and increased recovery of valuable minerals. The recent development of on-line techniques for analysis of coal is expected to be of similar Importance. Australian developments in on-line nuclear gauges are reviewed. These include systems for in-stream analysis of mineral slurries with comments on plant operating experience; on-line determination of ash in coal using low energy Y-ray transmission and pair production techniques; in-stream determination of solids weight fraction and ash content of coal in slurries with variable voidage; and on-line determination of moisture in coal, iron in high grade iron ores and sulphur in lead sinter.

Jan 1, 1986

The region we call the West Coast is acknowledged as one of the richest and most diverse mineral provinces in the world. It&apos;s the most rugged part of Tasmania and our island is one of the most rugged parts of Australia, so that speaks for itself. A hostile land of razorback mountains, deep ravines, dangerous rivers, almost impenetrable rainforests and a climate that can change from mild to freezing in a matter of hours.

Jan 1, 1993