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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

The information age has arrived. In every aspect of life, at the end of the second millennium, computers and information technology have made significant inroads. In mining there has been huge growth in the use of digitally controlled systems. From resource evaluation to mine planning to daily operations, information is being acquired, analysed, modeled and presented, using state-of-the-art information technology. Explosives, too, have moved into the information age. Computer controlled trucks and manufacturing plants have been developed and are now a regular feature on many mine benches. The next challenge for the explosives industry as a whole is to integrate blast initiation with information technology. The benefits are there, both to the supplier and to the end-user. Much has been written in the past about the potential for blast improvement but there are other significant advantages to a digital initiation system. These include security from unauthorised use, stock control and minimisation, reliability through testability and ease of use to name a few. So why is it taking so long? Surely the complexity of an electronic initiation system is far less than that of mobile phones that have been around for a long time. The answer, it seems, lies in the level of new technologies that need to be developed. There are enormous technological hurdles to be overcome in order to put into the market a cost-effective, reliable, user-friendly electronic initiation system. The most significant of these are:Safely and reliably initiating an explosive from an electronic device powered by a small capacitor. Prior to the development of electronic detonators primary initiation of explosives was by shock tube spit or by passing large currents and voltages down a pair of wires. Electronic detonators do not have that luxury. For example the energy stored in a æBeethovenÆ exploder is more than 500 times greater than that available to an electronic detonator. Communicating to a multitude of devices over very long cables installed by miners in harsh conditions. The deployment of an electronic detonator system has been likened to building a large telephone exchange in the rain and getting it to work perfectly first time! New communications protocols needed to be developed and tested. Wiring and connection systems have to be designed to survive the mining environment. In spite of these technological hurdles most of the major explosives manufacturers have persisted with electronic initiation systems and we are now, in 1999, starting to see the results of these multi-million dollar efforts. At SMI we are often asked many questions about this technology. The remainder of this paper seeks to answer those most often asked. As with any business linked to information technology todayÆs breaking news is tomorrowÆs archive and we expect the rate of development and understanding to accelerate as these technologies become accepted by the global mining industry.

Jan 1, 1999

By J Brisebois

The Wisemans Creek derelict mine site is located in native forest approximately 150 km west of Sydney. Mean annual rainfall at Bathurst, 20 km to the north, is 634 mm and reasonably distributed throughout the year, with slightly more rain falling in the summer months. Evaporation is 1350 mm per annum and considerably exceeds rainfall in all but the winter months (May to August). This results in a water deficit for much of the year. Groundwater is relatively deep, as it has not been intercepted in the shallow open cut workings. Investigation of the groundwater regime was beyond the scope of the current study. Mining has taken place on the site for almost 100 years, during which copper, talc and gold have been sequentially extracted from surface and shallow underground workings. The site is now characterised by the presence of small open pits, unprotected shafts and adits, mullock heaps and an unconfined tailing deposit from a small cyanidation plant. From a distance, the mine area is visible because of two distinct steep bare slopes below the relatively small mine workings and mullock heaps. The mining area was characterised in terms of its environmental, safety and heritage issues. Mullock from the early copper mining was found to be acid forming and leachate from this, combined with clearing of timber, has most likely resulted in death of vegetation below the heaps. The mullock also contains elevated concentrations of heavy metals. The gold tailing is apparently benign and not acid forming, although there are indications of oxidation and acid formation in the derelict gold open cut. Oxidation of the acid forming mullock still appears to be taking place even after being exposed to the atmosphere for at least 50 years, resulting in continued contamination of the slopes below the heaps with heavy metals. The concentrations of metals decreases with distance below the mullock heaps and also is confined to the ground surface the further away from the mullock, providing further evidence to support the theory that the mullock is the source of contamination. Despite this continuing contamination, its spread beyond the immediate mining area appears to have been limited because of the relatively dry climate, with only intermittent rainfall and stream flows. Irregular storm flows in the nearby creek could also have washed any contaminated soil some distance from the site and beyond the area investigated in this study. Remediation of the site and restoration of vegetation on the bare slopes will therefore depend on elimination of the source of acid and metals. Options for remediation, focussing on minimising cost by retaining the materials on or close to the site, are identified. The volume of the open cuts would appear to be close to that required for burial of the acid-forming mullock, thereby removing the source of surface contamination while keeping it above the groundwater table. However, implementation of this remediation plan will depend on the availability of funds to undertake the work through the New South Wales GovernmentÆs Derelict Mines Program.

Jan 1, 2003

The Macquarie Dictionary defines `information' as: knowledge communicated or received concerning some fact or circumstance; (in communicating theory): a quantitative measure of the contents of a message. For mining companies investing in data capture and information processing technology for operations management is a key issue. Beyond producing performance related information that employees can relate to it is being able to deliver that information into the workplace when it is required, to the employees that can utilise it. To be effective the data needs to be received and understood as `information'. The technology is now available and proven to enable `information' to be delivered into the mining workplace adding value to the activities performed by mine employees. The application of computers and information technology in the mining industry has typically been limited to the resource definition and planning stages, accounting and administration and the process plants that treat the ores and minerals. The mining extraction processes that consume expenditure and determine output in a mining operation occur in an environment dominated by unpredictable events and variable conditions. The mining operation has long been regarded as an inexact science conducted in unpredictable circumstances with many independent variables affecting the output and resultant cost of production. Financial accountants keep track of expenditure and management accountants analyse the cost of production usually on a weekly or monthly basis but all this effort can't affect the outcome, that was determined by the real time events and variations of circumstances over a week ago. Such reporting and analysis can result in conclusions being drawn about what improvements can be made and how you might do better next time, but generally the data is not detailed enough, is inaccurate or misrepresents the real issues. The capital investment required for any mining operation is substantial and comparable to other industries such as manufacturing. The performance and utilisation of manufacturing plants is usually closely monitored down to the lowest level of detail. Many modern plants are controlled and optimised using programmable intelligent devices and monitors display real time performance to the operators and prompt them to make informed decisions to maximise production and minimise wastage. Technology suitable for the mining industry is now widely available and has proven to be a reliable and powerful tool for the optimisation of mining operations. This paper focuses on the latest information technology developed by Modular Mining Systems that has been implemented in mining operations worldwide. The benefits reported by the mining companies utilising real time information technology over the past 15 years have generally related to optimisation of truck fleet allocation and material blending. Some mining operations have reported improvements in equipment utilisation of greater than 20 per cent. With the development of real time graphical display screens in the operators cabins the benefits of information delivery can be harnessed to make employees more effective in the workplace.

Jan 1, 1995

A study was undertaken to investigate the relationship between the quantity and value of economic demonstrated resources discovered for 12 mineral commodities over a ten year period and the expenditure required to yield such mineable resources. The results showed that for every dollar spent on exploration, there is an apparent in-ground average value of around $54 dollars contained in the economic resources found. While this appears to be a satisfactory return, it should be remembered that more than 99.9% of exploration programs are judged to be failures because a viable ore body or mineral deposit was not proved up. What is behind this seeming paradox?   The fundamental truth behind mineral exploration is the fact that the more you explore, the more you find, and that one success will often lead to further discoveries. It appears that one rich and viable deposit creates such surplus that its inherent high value ('the pot of gold') makes up for all the failures. In short, mineral exploration is a high risk business with uncertain returns. However, with skill, enthusiasm, experience and venture capital, it can yield larger than normal returns for the brave and the fortunate.   Analysis of exploration expenditure and economic resources discovered for the period 1987 to 1996 revealed that the apparent in-ground value of economic ore discovered per dollar of exploration expenditure varied from a high of $429 for iron ore and $261 for bauxite to a low of $22 for gold and for lead, and $5 per dollar of diamond exploration expenditure. Preliminary conclusions drawn on the reasons for the variations observed include the inherent ease or difficulty of discovery for different mineral commodities which may in some cases, relate to the natural prospectivity of Australia as a whole. Layered deposits like iron ore and bauxite appear to yield higher in-ground value returns on the exploration dollar. To some explorationists, this may be considered as seemingly obvious, but it may have more to do with very large-exploration tenement grants pursued by various Australian State Governments in the early 1950s and 1960s than the apparent ease of delineating a stratabound deposit.   Despite the apparent relatively low in-ground value produced by the gold exploration dollar of $22, the 5660 tonnes of gold discovered in this ten year period was worth $9.1 billion and representing over a quarter of the new mineral wealth created in the ten years to 1996. This contribution, along with that from the other minerals discovered over the period, led to a significant boost to Australia's export income and standard of living.   It is concluded that, given the nexus between the amount of mineral exploration expenditure and the quantity of new resources likely to be discovered, this knowledge may help policy makers seek to influence the rate of resource discovery in countries like Australia for the benefit of the nation.

Jan 1, 2004

Since the initial discovery of phosphate rock resources in North West Queensland in 1966, significant changes in ownership and development direction have occurred. Initially development of the resource involved beneficiation to produce a more saleable grade of phosphate rock. However more recently development has focused on the production of a high analysis fertilizer product on the minesite. These changes have been influenced by economics, industry/government cooperation and a changing phosphate industry.

Jan 1, 1998

By Sen S. K, Banerjee D. D, Nandy D. K

It has been stressed that the intrinsic spon- taneous heating characteristics of a coal is not enough in predicting spontaneous fire risk of a mine. The influence of extraneous conditions created from the system of mining operations are also to be reckoned with, A case study was made with a mine in Jharia field, India, being proposed to be developed under short wall method with complete extraction in 4-5 slices followed by stowing.

Jan 1, 1988

AustraliaÆs strong position as an aluminium producer and potential magnesium producer combined with rapid market growth in the automotive industry, proximity to Asia and other natural advantages points to considerable opportunity for downstream processing and manufacture with light metals in this country. Development of a vertically integrated light metals industry in Australia needs to be pursued with vigour, as does the continued development of global strategic alliances through the value adding chain.

Jan 1, 2000

The restructuring of the minerals industry has created new challenges for the design and delivery of professional development, and difficult decisions for potential participants. New technologies offer some new methods of delivery, but fall short in providing all of the benefits of face-to-face participation. This paper is intended to be a catalyst for discussion of the issues involved in delivery and participation in cost-effective, relevant and timely professional development.

Jan 1, 2000

Reliability is not only important in coal mine planning, production and control. Reliability is also most important, and indeed is fundamental, to successful coal exporting.Coal preparation, blending, distribution, marketing and utilisation are areas of the coal industry in which reliability can be critical to coal exporting. Major elements of reliability which impact on coal exporting include coal quality, supply performance, -coal ownership changes, governmental regulations and policies, market reputations and differences in export markets.

Jan 1, 1991

While international coal trading operations often involve relatively small contract quantities, delivered over short periods or even in single shipments, most coal is supplied under long term arrangements. In entering into these arrangements the customer needs to be assured that coal of suitable and consistent quality can be supplied for their duration in the volume required. A detailed knowledge of the mine and transport system is required and must be presented from the customer's perspective.

Jan 1, 1983

By Gillies A. D S

The paper presents a review of research in the area of explosible coal dust with respect to safety in the underground mining environment. Research over the last several decades has concentrated on generating dust clouds in small scale laboratory explosion chambers to study flammability limits and the physical and chemical variables which affect explosion propensity. The validity of this approach is discussed and the results obtained for a range of coal types compared.

Jan 1, 1994

This paper provides an overview of current and future mine developments in the major island nations Indonesia, Papua New Guinea (PNG), New Zealand, and Fiji, and the French territory of New Caledonia. Many of the other 11 small island nations in the region, such as Vanuatu, Pulau and the Solomons have been the subject of considerable exploration orientated towards gold in the past few years but without any deposit found with confirmed economic viability.

Jan 1, 1990

Cobar Mines Pty. Limited (CMPL) uses sodium sulphite as the principal depressant to attain selectivity in copper flotation prior to sequential recovery of lead and zinc. The usage of sodium sulphite is examined both from a theorectical viewpoint ana from the manner in which the copper circuit at (MPL has developed. The results of relatively recent investigations, both in the laboratory ana the plant, are discussed aria shown to support the present operating Techniques.

Jan 1, 1983

By Seedsman RW, Duncan Fama ME

Mine design procedures will be revolu- tionised by technological developments in computers, software, database construction and management, and numerical modelling programs. Developments in geotechnical databases will be required which utilize geological and geomechanical tests to supply appropriate input for numerical models. Techniques utilizing sedimentological and structural modelling are described. The capacity of current numerical models in mine design is outlined and a program for developing a fully integrated mine design package proposed.

Jan 1, 1987

The Mount Morgan massive sulphide body occurs in a volcanic sequence of Lower or Middle. Devonian age, which is subdivided in the mine into "Upper mine porphyries", "Banded mine sequence", and "Lower mine porphyries". This sequence is intruded by latite, Mount Morgan Tonalite (360 million years), and late Permian dykes. Distribution of macroscopic ore textures and minerals in the orebody are discussed and evidence is presented indicating the pre-Tonalite, Devonian age of the orebody.

Jan 1, 1974

Sublevel open stoping was introduced at Rosebery in 1972; most of the stoping prior to this was horizontal cut and fill. Sublevel open stoping presently accounts for 65% of the Rosebery underground production of 560 000 tonnes per year. This primary stoping technique leaves 50% of the ore in the crown and transverse pillars. The methods used in pillar recovery to date are reviewed and comments made on the success of these operations.

Jan 1, 1982

By A M. Mueller

St Helena tunnel is the centrepiece of the Pacific Highway upgrade from Tintenbar to Ewingsdale, abbreviated and commonly known as T2E. At the deepest point the twin tunnels run 45 m below the ridge line of St Helena Hill, located about 5 km west of Byron Bay. The tunnel breakthrough was achieved early in 2014 and the works for permanent lining will be completed in early 2015.Once the project will be handed over to the public in 2015, T2E will deliver a safer highway and uninterrupted traffic flow between New South Wales and Queensland. The design speed in the project area has been set to 110 km/h by the client Roads and Maritime Services (RMS), which will reduce the travel times between Brisbane and Ballina to just over two hours.The two tubes of the tunnel have been designed to accommodate three lanes in each direction with shoulders and walkways on either side of the carriageway. These requirements result in a huge cross-section of about 20 m width and an excavated area of about 210 m2.With the tunnel alignment being situated in basaltic rock, St Helena tunnel is conventionally driven. The selected excavation method was predominantly drill-and-blast with temporary support being installed immediately after the excavation. Despite the wide span of the tunnel, the geology allowed the tunnel perimeter to be supported by only rock bolts and a layer of shotcrete over the majority of its length.Due to environmental reasons one of the approval criteria of the project was that the tunnel must not have a detrimental long-term impact on the groundwater system within St Helena Hill. Consequently the tunnel has been designed as a fully tanked structure with a waterproofing sheet membrane installed on the temporary shotcrete.The permanent structure of the tunnel has to meet a 100-year design life and it is designed as a cast in situ concrete lining. Considering the water pressure on the lining the concrete is reinforced with a significant amount of bar reinforcement.The presented paper provides a more detailed explanation of the geology and the consequential temporary and permanent support measures together with the waterproofing system.CITATION:Mueller, A M, 2014. Pacific Highway upgrade from Tintenbar to Ewingsdale (T2E), St Helena Tunnel, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 419–424 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Saghaeian, A H. Baladastian, A Dehghani Ahmadabadi, V Sheikhzadeh, R Hejazi

With the declining of high-quality hematite and magnetite iron ore reserves and the increasing accumulation of material resulting from mining and beneficiation operations that appear as lowquality depots and discharged materials in tailing dams, the necessity of recycling these reserves is increasingly becoming a critical demand. The Chadormalu iron ore mine is among the largest deposits of magnetite-hematite iron ore in Iran. In this mine, the total wet processing tails accumulated in tailing dams are over 92 Mt containing 25–40 per cent Fe. Laboratory and pilot tests on tailing samples led to the design and implementation of the Chadormalu Tailing Recovery plant (CTR) with a unique process circuit in Iran. In the CTR plant, after three steps of re-pulping with spiral classifiers and sanding machines, the underflow is concentrated by two stages of WMIMS and produces 64 per cent Fe grade magnetite concentrate. The tailings of the drums are mixed together and introduced into the hematite recovery section, including two stages of VPHGMS separators, and 60 per cent Fe grade hematite concentrate is produced. This plant has been in operation for over ten years with a total yield of 18.93 per cent. Due to changes in the materials extracted through new tailing dams, the quality of the final concentrate dramatically dropped to 56.36 per cent Fe and 0.79 per cent P; therefore, applying reverse flotation and removing phosphorus from the final concentrate was inevitable. By using this approach, upgrading of the concentrate to 63.01 per cent Fe and 0.05 per cent P was obtained. Furthermore, regarding the high amount of phosphorus in the tailing streams, direct flotation has been designed to produce apatite concentrate as a by-product stream through a flotation system comprising series banks of Rougher, Cleaner, and Re-Cleaners flotation cells. Hence based on the results, at optimum conditions, a final apatite concentrate with a yield of 15.78 per cent and 14.06 per cent P could be achieved. Successful implementation of this project has led to the production of magnetite-hematite and apatite concentrates with annual capacities of 250 000 and 45 000 t, together with total yields of 11.59 per cent and 6.19 per cent (includes de-sliming of apatite flotation feed), respectively.

Aug 24, 2022

Water rights and availability are extremely contentious issues in many mining regions around the world, in some instances leading to violent confrontation. This situation has the potential to only get worse because competition for 'scarce' water resources will increase with population growth. In this environment the dilemma facing the mining industry is how to generate confidence in developing a responsible, sustainable and transparent water management strategy that is recognised as such by all stakeholders. Whilst the water needs of the mining industry are minor compared to those of agriculture, an operating mine requires a relatively large quantity of water on a daily basis to carry out operations. Another contentious aspects of new mine development is the debate between all stakeholders on the amount and quality of water that a mine is able to discharge into the environment should this be required. There are a multitude of water resources available to the mining industry for operational needs however much of this water is saline and over the last two decades there has been a continual decline in water quality (ie salinity has increased). In today's world there are enormous internal and external pressures to reduce water consumption at a mine and/or alternatively use water not considered a resource by the local community (ie sewage, saline or salt water, desalinated water). Strategies to meet these objectives can be achieved by implementing good water management practices, by recycling process water, reducing water losses by evaporation and seepage (ie by increasing and improving dewatering practices) and employing new technologies such as dry stacking and dry processing. Recycled water, acid mine drainage water and water collected in the mining area have the potential to impact mineral processing performance, unless they are treated, because of the build up of mineral salts and decomposed chemical products in these types of waters. Besides this the regulatory requirements of any water discharged from a mine site (quantity and quality) have also become more stringent. For these reasons there is now some form of water treatment practiced at most mining operations around the world. This paper provides an overview of water stewardship undertaken in the mining industry over the last two decades and provides examples of water treatment practices that have recently been installed at mining operations that may be of interest to the reader.

Sep 13, 2010