Search Documents

By D Thornton, R Hodson, D Sprott

Blast fragmentation size distribution and thus blast design have been found to have a direct impact on the load and haul cycle through excavator dig time and bucket payload. Previous studies have demonstrated that by reducing the excavator dig time and increasing bucket payload, significant improvements can be made in both productivity and unit cost. Simulation work reported in the literature indicates that a 20 per cent improvement in dig time may result in only a three per cent improvement in load and haul productivity and unit cost. At the same time, a ten per cent improvement in bucket payload will directly translate to a ten per cent improvement in load and haul productivity and unit cost. Based upon these findings, extensive laboratory and field work have been undertaken in the past to correlate blast fragmentation distribution to bucket payload. In contrast, the literature reports limited studies quantifying the impact of blast fragmentation on excavator dig time. Field work was conducted at Placer Dome Asia PacificÆs Granny Smith Mine (Wallaby Pit) in Western Australia, concentrating on quantifying the impact of blast fragmentation on the dig time of a Liebherr 994 hydraulic excavator (shovel attachment with 14 m3 bucket). Fragmentation was assessed for each truck load of material using the Split Desktop system, while the excavator cycle analysis was conducted manually. Measured fragmentation P80 (fragment size at which 80 per cent of material passes) values ranged from 200 mm to 1200 mm. The field study investigated the impact of various fragmentation parameters (P20, P50, P80, cumulative per cent passing 250 mm size fraction, and uniformity index) on the average and total dig times. The results indicate that the fragmentation P80 provides the best correlation to average dig time (total dig time divided by the number of bucket passes to load a truck). The total dig time was found to be dependant upon the fragmentation P80 and the number of bucket passes to fill a truck. Monte Carlo simulation results, based upon these relationships, indicate a 26 per cent improvement in average dig time and a 12 per cent to 46 per cent improvement in total dig time (bucket passes ranging from 4 to 8), with a change in fragmentation P80 from 600 mm to 200 mm.

Jan 1, 2003

By C Staak, H Mischo, A Fichtner, F Reuter

In mining and remote areas of resource industry, there has been a development towards lacking emergency medical first aid response, that creates a potential disadvantage for patients after work accidents and other medical emergencies compared to standard population. This raises the question how a professional emergency medical coverage can be provided underground, taking into account lacking medical professionals in small resource companies combined with long rescue times. Aiming on the closure of this gap, a team of the mine rescue brigade from the Research and Training Mine Reiche Zeche (Forschungs-und Lehrbergwerk (FLB) Reiche Zeche) of the TUBAF Technische Universität Bergakademie Freiberg in Freiberg/Germany and its cooperating emergency departments of the Freiberg District Hospital and the Zeisigwaldkliniken Bethanien Chemnitz developed a totally new rescue concept using elements from tactical medicine and advanced emergency medicine combined with a specifically designed compact equipment and a highly standardised teaching curriculum. A fully new standardised and condensed tactical medical approach was developed including specifically adjusted equipment, and was taught in a didactically optimised way within 16 lessons in two days. Objective Structured Practical Examinations (OSPE) using manikins and simulated patients were conducted and compared to the identical exam of the reference group, which consisted of advanced paramedics. The standardised tactical medical scheme includes vital functions and body checks, advanced life support, nasal and intraosseous drug application, supraglottic airway management, artificial ventilation, thoracocentesis, bleeding control including tourniquet, fracture repositioning and splinting, transport bedding and thermal preservation. The developed Tactical Medical Mining Rescue (TMR) concept was subsequently included in the German guidelines for mine rescue services in 2022 and is already implemented in many companies in Germany and several international projects.

Sep 1, 2024

By Waterhouse J. D, Harris B. M

This paper briefly describes the construction in 1979/80 of a 70m deep trial open pit coal mine near Bowmans S.A. and describes more fully the hydrogeological aspects of the exercise. The primary purpose of the Trial Pit was to provide a large sample (700 tonnes) of coal for combustion tests to be carried out in West Germany and the United States of America. Consideration was given to obtaining the sample of coal by drilling and by shaft sinking as alternatives to open pit methods. It was expected that economic mining of the deposit on an operational scale could only be achieved by open cut methods and it was recognised that major uncertainties existed in planning such a mine in the deep unconsolidated multi-aquifer deposit. It was therefore elected to obtain the bulk sample by constructing a trial open pit, which would be closely monitored to provide as much data as possible for future planning of a full scale mine. The dewatering of the Trial Pit was achieved using 26 deep pumping wells, assisted in the later stages by several hundred well points. This was probably the largest dewatering project currently in operation in Australia.

Jan 1, 1981

In recent years there have been many changes in mine ownership due to the on-going rationalisation towards larger mining companies. Larger companies inevitably find it hard to manage small mining operations and in many cases smaller mines do not fit corporate resource, production and profit criteria. Smaller companies are more suited to managing these medium or small scale mines and are tendering for the purchase or lease of mines that larger companies wish to dispose of. In addition to these factors there has also been a trend (especially in Western Australia) for mines to continue operating at ever increasing depths. This in turn has led to more mines operating in high stress environments and experiencing damaging seismicity. Assessing the viability of seismically active mines from a takeover or purchase point of view should involve analysing the risk profile of every aspect on mining that could be affected by adverse seismicity. This includes assessing current and alternative mining methods, mine designs, support systems, extraction sequencing, monitoring and blasting. This paper includes discussion on items that need to be assessed when considering the purchase of seismically active mines, with experience gained from some recent studies in Western Australia. In these cases it was apparent that quantification of previous seismic history on itÆs own was a totally inadequate method of assessing minewide seismic risk potential. A more holistic approach is required, taking into account all aspects of relevant data, all the minewide effects of seismic activity and all possible means of mitigating those effects.

Jan 1, 2002

By J F. H Thompson

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Mineral exploration and mining are challenging businesses. Remote and at times harsh conditions have always made it difficult for exploration, but modern explorers also have to deal with cover, numerous technologies, an explosion of data and critical early community engagement. Mining deals with the reality of moving and breaking thousands of tonnes of rock each day to extract what can be a very minor component of economic value, and, furthermore, society expects that this will be done in a clean and sustainable manner. The exploration and mining challenges appear disparate, but they are intimately related.Although not widely appreciated, both exploration and mining have a long tradition of innovation. Over the last 50 years, major step changes in exploration have resulted from radical advances in our understanding of ore forming processes, new geophysical, geochemical and remote sensing technologies, and new ways to integrate and interrogate data. Over a more extended period, close to 100 years, mining has developed bulk surface and underground methods, selective extraction through flotation and leaching and global positioning system–geographic information system control systems that collectively facilitate mining at a massive scale. And yet, in spite of these successes and the boom that we have enjoyed in the last ten years, the industry is under pressure and the need for innovation and change is paramount.The major drivers for innovation are the need for increased quality in discoveries and mines and the need to interact effectively with communities and jurisdictions such that the benefits of quality mines are recognised and enjoyed widely.We are still making new discoveries around the Pacific Rim and elsewhere, but many argue that the quality – grade and accessibility – of these discoveries is decreasing. The net result is that explorers are delivering resources and reserves for development at lower grades and with higher capital and operating costs than current operations. For mining, the increasing age of many existing operations contributes to increasing costs, which, when combined with decreasing cut-offs and lower grades, also results in declining quality. The combined picture does not look good.Just as the pressure to improve performance and margins in the face of declining inputs increases, we are simultaneously faced with increasing societal demands for improved environmental performance and sustainable practices. This is most apparent at the local, community level, where opposition ultimately leads to delays or even cancellation of new projects. Quality is again the issue – quality of the initial and ongoing engagement and quality of the proposed mine in terms of environmental and economic performance.CITATION:Thompson, J F H, 2015. Exploration and mining – the need for innovation , in Proceedings PACRIM 2015 Congress, pp 45–48 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By N Boughen

This paper synthesises the findings of five studies undertaken by the CSIRO Wealth from Oceans Flagship in 2009-10. This research explores the concerns, expectations, and information needs of a range of stakeholders, (ie government, seafloor exploration and mining industry, other marine industries, environmental non-government organisations (NGOs), community members) in relation to the possible exploration and mining of minerals and aggregates from the seafloor, as well as the conditions for meaningful engagement with communities regarding seafloor exploration and mining (SEM) activities. The SEM industry has been described as the ‘next minerals frontier’, as incentives to explore and mine seafloor resources increase because of diminishing reserves of easily accessible onshore mineral and aggregate deposits. However, the conditions (if any) under which SEM would be acceptable to stakeholders (notably the public and regulators) have not been established. This work seeks to address this gap and ascertain the levels at which potential environmental and social impacts become unacceptable to those stakeholders. The research follows an earlier phase of studies undertaken in 2006 - 2008 that: identified the opportunities and barriers to the development of SEM in Australia, took the first step towards understanding the public and political contexts surrounding the industry, and mapped the positions of key stakeholders and captured their major issues and concerns. Together, these two phases of research confirm that environmental concerns dominate stakeholders’ responses to the idea of an expanded industry. However, the most recent phase of research has also found that, similar to current onshore scenarios, reservations due to environmental concerns do not completely outweigh social and economic objectives. This is provided stakeholders feel confident that there are systems in place (regulatory frameworks, watchdogs, independent research, and stakeholder consultation) to ensure that all interests are protected. When making decisions about the social acceptability of potential seafloor mining, stakeholders favour a precautionary approach, supported by rigorous scientific analysis of the potential environmental impacts, transparent and socially responsive management processes, and meaningful stakeholder engagement. This paper outlines the details of these findings, which may also be relevant to understanding the social acceptability or ‘social licence to operate’ for other future mining scenarios featuring a new approach or technology.

Nov 22, 2011

By Stokes WPC

The capital requirements to develop a new mining venture are becoming very large; amounts of the order of US$1,000 million are not now unusual among estimates to bring new mining complexes into production. At the same time prevailing political and economic conditions are making it increasingly difficult to determine whether or not a project is likely to be viable. These factors emphasise the need to carry out thorough evaluation studies of all mineral prospects before making major investment. Additionally with the rapidly changing economic climate existing at the present time, it is becoming more and more necessary to carry out reappraisals of existing mines. An important function of both initial evaluations and reappraisals is to provide the operators of the mine with effective mining plans to ensure that the operation will meet its required economic targets. P, p M. tl p b, c v, s c 1 n 1 f r d c e c e u w Modern computers are well equipped to store and manipulate large amounts of data with speed and reliability. Their use in the mining field r is increasing and this trend serves to free f technical staff from much of the time consuming m and error prone hand calculations which were o formerly required in determining reserves and w carrying out all forms of mine planning. r Nevertheless, computers are not a universal

Jan 1, 1980

The Mt Sinivit gold project is located approximately 50km SSW of Rabaul in the Baining Mountains of the Gazelle Peninsula, East New Britain Province. The deposits were discovered in mid- 1983 and form part of a larger 26km long zone of variably aurif- erous quartz veining. There are no surface indications or previ- ous records of any prospecting activity or production from the region. The Mt Sinivit deposits consist of a series of oxide and sulphide reserves and resources contained in the Wild Dog (South- ern, Central and Northern oxide zones; Northern sulphide zone) and Kavursuki veins. The proposed exploitation of the oxide reserves by a series of small-medium sized open pits has been fostered by the PNG Department of Mining & Petroleum (DMP) as part of a government policy to encourage the development of a small-medium sized mining industry in the country. The aim of this paper is to document the steps and procedures involved in obtaining the grant of a Mining Lease emphasising the time and the expenditures required during each step of the approvals process for the Mt Sinivit project.

Jan 1, 1997

By X Li, M-F Zhou

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Yinachang deposit in south-west China contains large amounts of Fe, Cu and rare earth elements (REEs). Apatite in this deposit records complex REE mineralisation and remobilisation processes.Fe-Cu-(REE) mineralisation at Yinachang occurred at ~1700 Ma, and three stages of alteration and mineralisation are identified: Na-(Fe) alteration, Fe-(REE) mineralisation and Cu-(REE) mineralisation. In the Fe-(REE) mineralisation stage, REE-rich apatite formed together with magnetite. In the Cu-(REE) mineralisation stage, fluids undersaturated with REEs interacted with early-formed REE-rich apatite, during which large proportions of REEs, especially light REEs (LREEs), were leached from apatite.At ~840 Ma, apatite experienced a second interaction with fluid. In that process, REEs were removed from the apatite structure but immediately reprecipitated into new phases within the apatite. Thus, numerous REE mineral inclusions including bastnaesite, monazite and minor Y-phosphate occur in the apatite. There are also a very small portion of LREEs that were transported out of the apatite, resulting in the growth of bastnaesite and monazite grains outside the apatite.This study demonstrates that REEs can be mobilised in multistage hydrothermal activities and highlights the significance of fluid compositions for REE transportation and deposition behaviours in hydrothermal systems.CITATION:Li, X and Zhou, M-F, 2015. Hydrothermal rare earth element mobilisation processes in the Yinachang Fe-Cu-(REE) deposit, south-west China, in Proceedings PACRIM 2015 Congress, pp 265–270 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By P Moser, P Schimek, F Ouchterlony

This paper summarises the findings of 27 model-scale bench blasts in magnetic mortar, which were conducted from 2011 to 2014 at the blasting site of the Montanuniversitaet Leoben.The aim of the study was the investigation of the influence of blasthole delay times in small-scale bench blasts on the face characteristics and cracking damage created in the surrounding rock, which affects the fragmentation in subsequent rows.The test specimens or blocks, which were produced out of magnetite concrete, were roughly 1:100 in scale to normal bench blasts. The confinement of the testing blocks at the sides and back ensured the similarity to normal bench blasts with regard to the wave transmission into the surrounding rock. The specimen contained three or four rows with five blastholes each and were shot row by row, with virgin (undamaged) material in row 1 and increasingly damaged or preconditioned material in the following rows.The tested delay times varied between 0, 28, 73 and 140 µs, which corresponds to 0, 0.4, 1.0 and 2.0 ms/m of burden.The evaluation of the material properties showed that the use of magnetite concrete eliminated the inhomogeneous behaviour of rock, but some unexpected differences of the individual production cycles were still detected.The characteristics of the bench after each blast was evaluated along three horizontal lines out of a 3D model of the bench face. The tested delay time sequences of the virgin (first row) and single preconditioned blasts (second row) produced more overbreak for longer delays, while the third-row shots resulted in a smoothened surface independent of the chosen delay.The introduced damage after every blast was evaluated by an observation of irregularities on the newly blasted bench face. The visible cracks at the top of the testing blocks were documented and divided into several crack families according to their angle, length and origin. The remaining block was broken out of the blasting site after blasting, cut into several horizontal and vertical slices and dye penetrant spray was used to visualise the cracks created. Some of the detected crack families showed an influence of the delay time. The calculated mean crack density and mean crack intersection density showed that longer delays resulted in a higher degree of damage.The fragmentation results were well reproduced by the basic three-parameter Swebrec function. The observed improvement of fragmentation in the second- and third-row blasts was linked to the preconditioning of the burden for the following row while blasting the actual row. With the exception of the simultaneously initiated blastholes, the blasts showed coarser fragmentation for the shortest delays, while the longest delays generated the finest fragmentation.CITATION:Schimek, P, Ouchterlony, F and Moser, P, 2015. Influence of blasthole delay times on fragmentation as well as characteristics of and blast damage behind a remaining bench face through model-scale blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 257–266 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By D H MACKENZIE

In common with several great orebodies and mineral camps around the world Broken Hill has been the subject of state-of-the-art technical and scientific scrutiny during its long working life. During the early years geological interest in Broken Hill tended to be directed at the body for its intrinsic scientific worth, mainly on account of its large size, high grade and wealth of mineral species. For much of the last 60 years the interest has had a more applied motivation, namely, to assist the search for either repetitions in the Broken Hill field or analogues in other terrains. This paper looks at the major changes in geological concepts and exploration techniques applied at Broken Hill and attempts to assess their impact.

Jan 1, 1992

By Hart A. T, Lanigan P. G

BHP is currently undertaking research into plasma are metallurgical processing at the Central Research Laboratories (CRL), Shortland. The use of high intensity plasma arcs for melting and smelting has a number of advantages, including; the ability to control atmosphere and furnace operating conditions, total enclosure, high temperatures, versatility, and low in-process inventory in a compact system. The intensive conditions, achievable in a plasma furnace system, make it particularly useful for the smelting and melting of difficult-to-treat materials, such as ore and metallic fines and refractory ores. Two transferred arc plasma smelting furnaces have been set up at CRL; a 100kg furnace is used for small scale melting and smelting studies and a 1 tonne furnace for pilot scale plasma processing studies and equipment development. Power is supplied by a 1MW GEC thyristor DC power supply. A 220kW DC power supply is available for "off site" pilot process trials and demonstrations, and a 150kW non-transfered are plasma torch is also available for other studies. The facility has been designed to allow maximum flexibility in researching and developing applications in metallurgical processing and transferring developed technology to company operations. The objectives behind the development of the facility, details of the facility and an outline of current research areas will be Discussed.

Jan 1, 1987

By N B. McCaffrey, V Glenn, C Johns, P D. Erskine, A T. Fletcher

"Underground coal mining is the dominant method of extracting thermal and coking coal in the southern and western coalfields of New South Wales. Monitoring mining-related subsidence forms an important component of environmental impact assessments and subsidence management plans, particularly when there are conflicts between the interests and requirements of mining and environment and community groups. However, there are few specific guidelines for monitoring the impacts of subsidence on terrestrial and aquatic ecosystems, leading to inconsistent policy approaches and highly variable abilities of monitoring programs to accurately detect biological change.This paper highlights the use of a conceptual framework to guide the development of a long-term ecological monitoring program at an underground coalmine in the Western Blue Mountains, New South Wales. Two pilot studies are described: determining the level of observer agreement to assess the condition of a vulnerable tree species (Capertee Stringybark) comparing field sampling methods for detecting a rare heath shrub, Epacris muelleri, using a power analysis to determine sampling intensity requirements.These examples demonstrate that investment in initial pilot studies to test different monitoring approaches can have long-term benefits for stakeholders by more confidently being able to detect potential impacts.CITATION:McCaffrey, N?B,?Glenn, V, Erskine, P?D, Johns,?C?and Fletcher, A?T, 2014. Detecting long-term ecological impacts of subsidence from underground coal mining – a tale of two pilot tests, in Proceedings Life-of-Mine 2014, pp 139–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By Loo R

The Paper discusses the size and extent of in-pit dust suppression problems created by iron ore mining in the Pilbara region of Western Australia. Dust problems associated with drilling, loading, hauling and tipping are discussed indicating the large quantities of water which can be applied for dust control and attempts that have been made to rationalise this water usage to obtain maximum benefits from the applied water. The magnitude of the problem and the quantities of water involved can be appreciated when one realises that 275 000 tonnes of rock are moved on Mt. Whaleback each day and that there are 40 km of haulroad within the open pit. Initially dust suppression was limited to the spraying of haulroads by large water tankers. Now dust suppression is practiced during drilling and after blasting, wind blown dust is reduced by application, using water cannons,of large quantities of water to floor stocks prior to loading operations as well as by the installation of 16 km of automatically controlled fixed sprinkler reticulation on the main semi-permanent haulroads. The methods used to assess the water requirements for in-pit dust suppression are discussed and the extensive development testing used to evolve the present installations are 1. Environmental Superintendent Mt. Newman Mining Co. Pty. Ltd. Newman, W.A. 2. Chartered Consulting Engineer, Perth, W.A.

Jan 1, 1979

By J Johansson

The aim of this paper is to discuss how to form work and organisations in the mines of the future. The Kiruna underground iron ore mine in the far north of Sweden is used as an example on how technical development affects organisational issues like skills, work identity and gender. Over a period of 50 years one can see a transformation of work from manual underground work to automation and remote control from surface level. What characterised the old underground workface was the close relation between man and the hard rock and with arduous physical work under dangerous conditions. Today, the face miners are located on the seventh level of an office building close to the mine. There is also an emerging, and in many aspects already evident, knowledge transformation û from the old and obsolete physical and tacit knowledge and skills (for example the ability to æread the rockÆ) to something new, which can be described as abstract æhigh-techÆ knowledge and skills. The modern technology has created a new type of work û new in terms of competencies and knowledge as well as workload and organisation. At the same time the mining company are recruiting more women and promoting the former pure male work as attractive workplaces for both women and men. All this has effects on how individuals and company create and recreate skills, identity and gender. To some extent the technological development predestines these changes, but there are some choices to be done when forming good work and organisations for the mines of the future. The traditional mining workplace culture and behaviours and the old type of masculinity, the æmachoÆ style, will be challenged by the new æhigh-techÆ work and new competency demands. The changes risk meeting restoring responses, which can have negative impact on the performance of the organisation, for example making it inflexible and perhaps ælaggingÆ behind the technological development. These questions need to be handled when planning future mining.

Jan 1, 2008

By T N. Little

This review paper presents an integrated and practical insight to blasting geology and its importance. This approach involves developing blasting objective up front and implementing geology specific blast designs. The author refers to this approach as ‘starting at both ends’. There are many human-imposed controls on blasting operations, such as: safety, security, legislative, company standards, heritage, and environmental constraints. Thus it is possible for some operators to lose sight of the controls imposed by nature. This paper demonstrates how site geology controls or influences many aspects of the rock breaking processes and how a focus on this aspect has potential to add considerable value to mining operations. It is obvious that mining companies concentrate their efforts on economic/ore geology (good rock geology). However it is the author’s experience that they also concentrate on engineering geology (bad rock geology) only when forced to do so by the ground conditions, but seem to run out of puff before they apply blasting geology (big rock geology). This paper contains five main sections. In the first section, the impact of geological controls on blasthole drilling is briefly discussed in terms of drill selection, penetration rates, bit wear, blasthole stability, blasthole deviation, and health precautions. In the second section the geological controls on aspects of geometric design are reviewed. These include: hazardous minerals, valuable minerals, selection of the blasting techniques, geological structures, blasting direction, and blasting geometry. Section three overlaps with the geometric design section and deals with aspects related to explosives. Topics addressed include selecting the explosive type based on geology, distribution of explosive charge in space and time, explosive performance, and the rock response to explosive loading. In the fourth section, examples are given of the operational complexity needed to implement a blast to cater for difficult bench geologies, environment constraints, past mining (voids) and need for a high degree of quality control. Section five demonstrates geological controls on blast results. Blasting results include the muck pile characteristics, downstream handling and processing, damage to the remaining rock, and blasting emissions.

Nov 8, 2011

By Osorio J. D C, McMahon M. D

Burwood Beach Sewage Ocean Outfall is being constructed by the Hunter District Water Board as part of an amplification scheme to eliminate pollution from adjacent bathing beaches. The outfall consists of a 93m vertical shaft, 1950m of 2.7m diameter tunnel with a series of diffuser outlets connecting the seaward end of the tunnel to the sea floor on a rock outcrop. The site of the work is in the Newcastle Coal Measures and the project is complicated by the proximity of colliery workings to tunnel alignment, although the colliery records provided valuable information on geological features. The location of the tunnel was determined to be in the Waratah Sandstone Formation immediately below the colliery workings after three different alternatives were considered. The shaft, which will be sized to suit contractor's construction methods and equipment, will be sunk through about 24.5m of alluvial material and 68.5m of rock. The tender documents were developed to allow the contractor considerable flexibility in construction method to suit available equipment. The specification also allowed great flexibility in tunnel construction method with minimum cross sectional area of 5.7m2 being the basis for a number of allowable alternative profiles ranging from circular to horseshoe.

Jan 1, 1987

By Martinick WG

In July 1986, Cable Sands (W.A.) Pty Ltd commenced mining for mineral sands at Minninup, approximately 16 km south of Bunbury, Western Australia.The area being mined is from the heel of the foredune to the rear of the hind-dune. The vegetation is mostly native vegetation with some old degraded pasture.The mining operation will be by suction cutter dredge, with continuous dredging, mineral separation and re-depositing of the sand.

Jan 1, 1986

By L Gladysiewicz

This paper deals with the current situation in the mining industry in Poland. An overview of typical transport systems working in the different branches of mining is provided. The transport systems currently used in lignite mining, particularly in the Belchat=w mine û the largest brown coal mine in Poland, and those operating in copper mines are described in detail. New designs of belt conveyors used in underground hard coal and copper mining are presented.

Jan 1, 2003

By S Juras

The terms measured resources and proven reserves denote the highest level of estimation confidence in all of the major classification schemes. But what do they really bring to today’s project or mine with respect to production planning and expectations? Initial reserve declaration does not need measured resources, just indicated resources. Economic viability of a project is assessed on total reserves with nary a bonus for the amount of proven reserves. Production plans are based on grade and tonnage goals that may only coincidently correspond to proven reserves. So are the measured and proven categories still relevant? Historically, and almost exclusively in underground mines, companies only allowed mining in areas of proven reserves. Some companies still follow that philosophy. But many others will mine a mixture of probable and proven reserves without hesitation. Also what of the undeveloped project in a new district – what is to be made of their declared measured resources and proven reserves? Measured resources are commonly set either by some type of proximity to data scheme or a matter of ‘feel’ based on the qualified person’s experience. The parameters for reserve conversion focus on the project as a whole and then a portion becomes classified as proven reserves almost solely based on whether the resource category is measured. So should the mining industry continue to use these categories of resource and reserve classification? This paper will present arguments about making these categories once again more relevant. A more disciplined usage of these categories may re-introduce their relevancy in public disclosures of resources and reserves. As well a more consistent usage in operations may lead to increased confidence in managing production targets and costs.

Aug 22, 2011