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By Ault A. R

The recent modernisation program at the Risdon electrolytic zinc smelter of Pasminco Metals - EZ (PMEZ) inyolved significant changes to the composition of cell electrolytes. The most significant were increased acidity and sulphate level, a reduction in Co level, and the replacement of 2-naphthol in the additive mixture with licorice. In determining acceptable operating ranges, a relatively large number of industrial deposition tests under controlled conditions was required. The cathode zinc deposits so produced were examined in terms of overall appearance, crystal structure according to X-ray diffraction, and a micro-roughness parameter. Beginning with typical deposits produced in the presence of an excess of one of the addition agents glue or antimony or a mist suppressant (licorice or 2-naphthol), a simple classification system was developed. In this system, the deposits are divided into the following types: Doughy, Pinholed, Compact and Stressed. There was a weak correlation between deposit type and crystal orientation. In terms of ease of stripping, observations in plant operations showed that only Compact and Pinholed were consistently acceptable. Current efficiency was normally maximised by producing a Compact deposit. Process variables such as zinc concentration, temperature and the use of strontium carbonate were found to cause changes in deposit type if the reagent mixture used was unchanged. From the knowledge gained, guidelines were developed to allow glue and antimony additions to be altered to fit new circumstances. The simple classification system was first used to expedite recovery from undesirable morphologies and then to optimise individual cell units operated under substantially different conditions. It is believed that finer control could be exercised by determining the micro-roughness of Compact deposits. However, difficulties can arise if sudden, large deviations occur and go undetected. Suggestions are given for an improved additive control system. The classification system developed has been compared with published information in the literature, and good correspondence was noted suggesting a predictable relationship between short-term, laboratory deposition tests and observable phenomena in industrial electrowinning cells run under steady conditions.

Jan 1, 1993

The following is a brief summary of the Bulli Colliery and its method of operation when Australian Iron and Steel Ltd. took control.Bulli Colliery is situated about a mile west of the village of Bulli and is some 10 mUes north of the Australian Iron and Steel Company's Steelworks at Port Kembla.The mine is owned by Australian Iron and Steel Limited, who purchased it in 1936 from the liquidators of Bulli Colliery and Coke Works.It is one of the oldest working coal mines in Australia, having been opened about 1858 and has worked more or less continuously since that date.The seam worked is the No. 1, or Bulli, Seam, which outcrops along the escarpment of the Illawarra Range and is generally operated by tunnels, the portal at Bulli being some 440ft. above sea level.The colliery holding is fairly extensive, but the coal seam over a large portion of the area within two miles of the outcrop has been more or less destroyed by an intrusion of basalt.At present there is no coal being worked within a distance of about 21 miles from the surface, the farthest workings being about four miles from the tunnel mouth.The existing main haulage road, for the first two miles from the portal, is not straight; it is very narrow over fairly long stretches and has many changes of grade varying from 3% in favour of the load to 13% against the load.The dumping station and screens are situated close to the portal of the haulage tunnel, and at this point the coal is loaded into railway hopper waggons, which are then hauled by rope to the top of a self-acting incline. The waggons are lowered down the incline, a distance of approximately! mile, the ruling grade being about 18 %.From the bottom of the incline, waggons are hauled by Company's steam locomotive to exchange sidings from whence they are taken by New South Wales Government Railway engine to the Company's Steelworks at Port Kembla.

Jan 1, 1947

By P Lamberg, M Lyyr, S Heimala, J Liipo

Since the introduction of froth flotation for industrial practice, the process has long been developed and improved by making cultivated guesses or by using trial and error methods to a varying degree. Fresh possibilities have emerged after development of new surface sensitive analysing methods and in situ electrochemical methods. Having had the possibility to combine different findings between science and everyday plant practice, Outokumpu has been able to develop a catch-all procedure to manage a flotation process taking into account the specific requirements set by different minerals in a slurry. A number of these procedures are available and offered globally to clients as part of a Plant Audit service. The Outokumpu Plant Process Audit (Process ef-X) concept comprises of mineralogical determinations from process samples and plant data analysis together with electrochemical process measurements using mineral electrodes. Automatic control loop analysis can also be included. The objective is to combine the results for a basis of flotation process improvement. Since this methodology has earlier been an in-house practice, it follows that the results are also reflected in the development and design of the OutokumpuÆs processing equipment. An increasing number of ores have a very intimate fine-grained texture and it may be physically impossible to combine high grade with acceptable recovery by a flotation process alone. For such cases, combinations of different hydrometallurgical û mineral separation û pyrometallurgical processes are available. Mineral specific information and chemical expertise of flotation technology can be utilised in development of other processes, as well.

Jan 1, 2005

By P J. Sack, L V Danyushevsky

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Regional-scale exploration for sediment-hosted gold deposits is hampered by the challenge of evaluating the fertility of ancient sedimentary sequences that host these deposits. Recent developments in laser ablation inductively coupled plasma mass spectrometry allow for the evaluation of the gold fertility of sedimentary sequences using chemistry of early-formed sedimentary pyrite. We present a case study from the Selwyn basin area of Yukon, Canada, where significant sediment-hosted gold exploration has been ongoing for the last five years. Data from sedimentary pyrite in some Neoproterozoic shales are anomalous in Au and As compared to a global data set of unmineralised sedimentary pyrite. If at least some of the gold and associated trace elements in sediment-hosted gold deposits are derived from recrystallisation of early sedimentary pyrite, it follows that strata containing anomalous sedimentary pyrite should be more prospective. Based on this premise, our data clearly show that Yusezyu Formation Neoproterozoic shales in the Selwyn basin area of Yukon are a fertile source rock for sediment-hosted gold deposits, while pyrite from Nadaleen formation shales are strongly anomalous in Hg and Tl, but not Au. We suggest that the area warrants continued exploration for sediment-hosted gold.CITATION:Sack, P J, Gregory, D D, Large, R R and Danyushevsky, L V, 2015. Using sedimentary pyrite chemistry to inform regional exploration for sediment-hosted gold deposits – a gold fertility case study from the Selwyn basin area, Yukon , in Proceedings PACRIM 2015 Congress, pp 69–76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Mines in the future deliver a paradigm shift in the way mining, material handling and processing are performed, unlocking significant value through production efficiency, flexibility and lower costs and enabling substantial safety and environmental benefits (V Schweikart). Mines in the future are highly productive, with low production costs and are significantly safer. They operate with a skeleton crew and use intelligent systems that fuse information from field instrumentation and other sources to generate the most efficient operating environment. Automated systems are seamlessly integrated across the mine and across the corporate enterprise. Geological models, long-term and short-term plans create optimised production schedules, suitably generated by the mine simulator. Production schedules are shared with the operations management system for deployment mainly by remotely operated and autonomous equipment. As the schedule is implemented, information is collected and shared with various plans, schedules, models and optimisation programs. This production environment is managed in real time from a æCentral Operations CentreÆ and it is visible across the business providing fast and accurate information about productivity, machine condition and environmental conditions. Central Operations Centres also house teams of subject matter experts that monitor and manage the mines and are able to communicate directly with the skeleton crew in the field. Constraints across the production line are displayed and managed appropriately from this location to maximise throughput. Maintenance is interactive and predictive. Reliability specialists in Central Operations Centres monitor the status of machinery and equipment and adjust maintenance plans and strategies to suit. Mining businesses rely heavily on knowledge workers û people with considerable knowledge and learning û and by manual workers. This new knowledge workforce is a team of associates rather than of bosses and subordinates. Field experts become leaders with tremendous autonomy regarding their work. The former line hierarchy becomes a support structure, intervening only in extreme emergencies; instead of giving orders, they are now removing barriers, expediting resources, conducting studies and acting as consultants.

Jan 1, 2009

By N Robson, E Stephens

Australian mining companies are actively exploring for and developing mineral deposits throughout the world with interests in emerging markets such as Africa, Asia and South America. It is important to understand emerging market risk as this will affect the willingness of mining companies and financial institutions to invest in a country, especially with reference to their key asset, the mining licence or operating/concession agreement. Mining companies looking to develop new projects in emerging markets have different risk profiles than projects in countries such as Australia and Canada. Examples of key risks faced in emerging markets include: political û expropriation, nationalisation, contract frustration, currency inconvertibility, war, terrorism, strikes, riots and civil commotion; and legal û mining legislation, arbitration and dispute resolution, trade agreements. There is a problem in the difference in risk perceptions between mining companies, financial institutions and insurers. This can cause different stakeholders to carry out different evaluations of the risks faced by a project, resulting in confusion about the risk margin attached to any project. In a time where resource nationalisation and energy security are prompting governments to become more involved in the mining sector we run through some recent examples of mining companies that have had problems due to the key risks highlighted earlier. Importance of carrying out the right due diligence to replace perceptions with reality: early identification of risks û detailed due diligence on emerging market risks that may arise will help with their identification and mitigation, make use of companies that can help identify risks and suggest solutions, control the cost of financing û risk margin applied to a project finance loan will be influenced by the risks faced, and risk management and using political risk insurance. There are plenty of opportunities in emerging markets but it is important to recognise the associated risks. Detailed due diligence at an early stage will provide long-term benefits.

Jan 1, 2007

The re-development of the Mount Charlotte gold mine in Kalgoorlie was carried out piece- meal as funds became available. Optimisation of productivity to offset the high risk which is a function of an indefinite gold price, has been the principal objective of the management.

Jan 1, 1980

By P Tobar

The development plan (long-term plan) of El Teniente Mine, Codelco-Chile, includes 100 per cent primary ore, located at increasing depths, which may involve several difficulties related to the application of the current panel caving method, such as a high seismicity level, a coarse fragmentation and ore pass damage. Therefore, it is a strategic priority for the El Teniente mine, to design and to test alternative mining methods, at similar or lower costs to ensure an efficient and safe ore extraction. In this context, the Macrotrench method is developed, as a competitive alternative to the current method. The document describes the panel caving method, the experience achieved in the primary ore exploitation from the geomechanical point of view. It also describes the æmacrotrenchÆ method as an alternative to the current exploitation method. Finally, the comparative advantages of macrotrench in relation to panel caving are presented. The results obtained during the engineering stage include the following aspects:the mining design, the material handling, a geomechanical evaluation of the method, and a comparative analysis.

Jan 1, 2000

By G R Ryan

Dissatisfied with conventional wet processing methods for alluvial deposits, Resource Trend Pty Ltd of Cairns set out to develop a better process. After comprehensive investigation of existing dry techniques the principals have now developed a rotary dry concentrator that can handle the fine-grained fraction of alluvial deposits as well as the coarse. Four of these units have been mounted on an integrated towable treatment plant which has been in successful commercial operation for four years in northern Queensland. A second plant is now under construction for use in the United States. Grades of less than 0.2 g/lcm have been profitably mined at throughputs of about 80 cubic metres per hour and 85 per cent availability. The operation runs round the clock with an establishment of four. Major benefits, apart from lower capital and operating costs, are environmental. Ore is picked up, treated, and replaced in its original mixed condition within 25 m of its initial location. Rehabilitation is completed almost immediately behind the plant as it advances, leaving no slimes dams, coarse stockpiles, or haul roads. In 1993 the company won a Premier's Award for Environmental Excellence in the Queensland Mining Industry. The principal disadvantage is moisture, and the company is now actively seeking deposits in the deserts of the world. In Queensland mining is normally possible only for six months of the year.

Jan 1, 1994

By Lewis PC, Carr GR, Dean JA, Glen RA

The Lachlan Fold Belt (LFB) is a complex orogenic belt which developed in Early to Mid Palaeozoic time. A number of orogenies and more localised deformational events affected the region. A simplified classification scheme for the diverse gold deposit types is proposed, subdividing primary mineralizing processes into four categories: volcanism (epithermal and volcanogenic deposits), igneous intrusion (subvolcanic/porphyry style, skarn and magmatic deposits), metahydrothermal processes (deposits generated during metamorphism and regional deformation) and hydrothermal-distal processes (deposits generated by poorly understood, generally remote large scale hydrothermal processes). Major gold deposit associations include epithermal and porphyry style deposits in Ordovician-Early Silurian shoshonitic andesite sequences; volcanogenic base metal-gold deposits in Silurian rift or basin felsic sequences; vein deposits in Late Silurian and Early Devonian S and I-type granitoids; deposits in Early Devonian sedimentary rocks of the Cobar Basin probably generated by metahydrothermal processes during basin closure and cleavage formation; deposits associated with serpentinite; and metahydrothermal quartz vein deposits in folded sedimentary rocks.Studies of host rock geochemistry suggest a relationship between magma types, gold enrichment and mineralization particularly in shoshonitic sequences and Early Devonian granitoids of the Boggy Plain Supersuite. Structural studies indicate the importance of thrust type structures and detachment faults in generation and location of gold mineralization. Lead isotope initial ratios help define metallogenic associations and a number of distinctive isotope "signatures" have been established.

Jan 1, 1990

By P N. Nkrumah, A van der Ent, G Echevarria, P D. Erskine

Nickel phytomining is a low cost alternative to traditional nickel mining and a complementary process to existing mining operations in areas with low-grade nickel soils or nickel waste material. The process of nickel phytomining consists of growing selected hyperaccumulator plant species (‘metal crops’) on Ni-rich (ultramafic) soils, followed by harvesting and incineration of the biomass to produce a ‘bio-ore’ from which Ni salts or Ni metal may be recovered (Chaney et al, 2007). The ‘metal crops’ are selected on the basis of high biomass yield combined with high Ni concentrations (>1 per cent) in the above-ground biomass (Chaney et al, 2007). Currently, Alyssum murale and A. corsicum have been used for Ni phytomining trials, mainly undertaken in Albania and USA (Bani et al, 2015; Li et al, 2003), while the agronomy of <10 species has been tested in temperate regions (Nkrumah et al, 2016). Nickel phytomining has high economic potential; however, large-scale demonstrations are needed to provide ‘real-life’ evidence for commercial operations (van der Ent et al, 2015). Unrealised opportunities exist in tropical regions for commercial scale Ni phytomining. To date, the agronomy of tropical ‘metal crops’ has not been tested. This extended abstract presents the progress of tropical phytomining, and reports on agronomic trials undertaken to determine whether the trends in temperate regions could be confirmed in a wet tropical environment.CITATION:Nkrumah, P N, Erskine, P D, Echevarria, G and van der Ent, A, 2016. Progress in tropical nickel phytomining, in Proceedings Life-of-Mine 2016 Conference, pp 135–137 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By N Barnett, M Dello-lacovo, J Oh, S Saydam, T Pelech

In-Situ Resource Utilisation and Off-Earth mining require the application of horizontal drilling. The stability of such openings is challenging when excavating in the lunar regolith. Excavations on the Moon will encounter unconventional operational conditions such as different material properties, low gravity, and a moonquake. Micro-tunnelling or drilling to support lunar exploration and development of infrastructure on the Moon requires stability analysis to ensure its desired performance. The discrete element method (DEM) modelling technique has been utilised to investigate the optimum opening sizes on the lunar soil. From the literature, the mechanical properties of the lunar regolith have been reviewed and used for numerical model development. The model has been calibrated by simulating numerical triaxial tests with the Mohr–Coulomb failure criterion. Then, detailed parametric studies have been performed to investigate the influence of confinement, opening dimensions and moonquakes on the stability of openings. The findings have led to the development of a simple stability chart of the relationship between unsupported opening sizes and lunar regolith properties at different depths.

Nov 29, 2022

A shift in the present day oil exploration scenario from West Coast can be foreseen keeping in mind peak of exploration in Cambay Basin and fast pace of development in Bombay High and its associated fields by the end of this century. Shifts in exploration from structural traps to stratigraphic traps, techno- logical development to drill in deep waters, improving economic situation for oil ventures and proven oil and gas potential of East Coast basins suggest that Indian oil explorat- ion scene will be at its peak along east coast during early 21st century. Hydrocarbon shows in Poonch and Jawalamukhi in Punjab Basin, improvements in drilling to greater depths, better seismic data aquisition, good source rock potential of Subathus and its equivalents and large geologi- cally mapped structures will reopen new avenues for explorationists. Not much exploration effort has been put up so far in Ganga Basin. Keeping in mind size of the basin, sedimentary thickness involved, presence of algal matter deposited in shallow marine environment & higher hydrocarbon indications warrant active exploration. Gondwanas in India having such a large sedimentary area can not be ignored keeping in view generation and production from the non marine sediments of Kenya, Chad, Sudan, Gadon and China. Gondwanas become all the more important in view of gas production from their equivalents-Karoos in Ethiopia and South Africa. In all, above mentioned changes can be predicted in Indian oil exploration scenario during 21st century.

Jan 1, 1986

A mathematical model for spontaneous combustion of coal with moisture included is presented in this paper. The one-dimensional unsteady state model consists of conservation equations for oxygen, water vapour and inherent moisture of coal and energy for both gaseous and solid phases. A first order Arrhenius reaction rate for oxidation under both pore diffusion and chemically controlled reaction regime is considered. The rate of evaporation or condensation is also considered as a function of temperature of coal, water content of coal and gas streams. The equation of the model is solved numerically by the finite difference technique. Influences of different parameters on the process of spontaneous combustion can be examined by using this model. Also the model can be used to simulate full-scale storage conditions.

Jan 1, 2005

By H Aoki, A Nakayama, K Morita, S Yamada

The thermal conductivity of mold flux is crucial for optimising the productivity and quality of steels. This study investigates the thermal conductivity of molten oxides, including CaO-BO1.5-AlO1.5 (CBA), CaO-BO1.5-AlO1.5-SiO2 (CBAS), and CaO-MgO-BO1.5-AlO1.5 (CMBA) melts, using a hot wire method. Additionally, their structure is examined using Raman spectrometry and magic angle spinning nuclear magnetic resonance (MAS-NMR) to explore their relationship. Furthermore, first-principles calculations are employed to assess the covalency of each bond in the melts for a more quantitative analysis of their relationship. The study confirms that an increase in the CaO concentration of the CaO-BO1.5-AlO1.5 melts reduces the amount of bridging oxygen and consequently decreases thermal conductivity. The covalency of the B[4]-O bond is highest, especially when the second-nearestneighbour Al atoms transition from Al[6] to Al[4], forming the AlB3O7 structure with B[4]. The relationship between thermal conductivity and the structure of CaO-BO1.5-AlO1.5-SiO2 melts can be quantitatively assessed using the degree of polymerisation of the network structure and the variation of covalency as indicators. Furthermore, replacing CaO with MgO in the CaO-MgO-BO1.5-AlO1.5 melts reveals a mixed alkaline earth effect on thermal conductivity.

Aug 21, 2024

By A Taheri, G D. Nguyen, M Karakus, S Akdag

During underground mining operations, rock masses are highly subjected to dynamic disturbance caused by blasting, mechanical drilling and earthquakes resulting in strain burst, slabbing and spalling. The dynamic fracture is a significant manifestation of rock failure in deep underground engineering, and it is of great importance to assess the dynamic fracture behaviour of the rock mass under elevated temperature conditions. The correlation between temperature – and loading rate-dependent dynamic fracture mechanism of strain burst is yet to be established. A good understanding of the dynamic fracture behaviour of brittle rock subjected to high-temperature under dynamic loading is required for the prediction of the damage extent during strain burst, and proper design as well as control of the underground rock structures. In this study, dynamic mode I fracture toughness tests are carried out on cracked chevron notched semicircular (CCNSCB) granite specimens to reveal the dynamic fracture characteristics of the brittle rock. For this purpose, a Split Hopkinson Pressure Bar (SHPB) apparatus is utilised to conduct the dynamic tests with various striker velocities on thermally degraded granite. The dynamic mechanical behaviour of granite after high-temperature treatment is examined and discussed. The dynamic fracture toughness is determined and compared for the specimens exposed to different temperatures at various dynamic impacts. The fracturing processes are recorded by a high-speed camera (HSC), and the crack propagation speeds are estimated by HSC image analysis. In addition, the dynamic fracture process and the coupled effects of temperature and loading rate on the dynamic fracture modes are identified by HSC image analysis. Energy partition characteristics in dynamic fracture of granite are quantitatively investigated.

Nov 29, 2022

By B Murphy, J van Zyl, G Domingo

In a narrow vein mining scenario, employing preconcentration technology underground not only results in reduced transport and handling costs but may allow alternative mining methods to be implemented, improving overall productivity. Using processing technology underground is not a new concept with underground crushing and screening operations being quite widely utilised. With advances in processing technology over recent years, there are now a number of robust processing methodologies in existence that are capable of performing separation of ore and waste at a relatively coarse size. Many of these technologies are readily adaptable to the underground environment and if employed could result in a number of cost and productivity benefits.Assessment of the oreÆs suitability for preconcentration technology is the first step in harnessing these potential savings. This paper discusses how coarse ore sorting and gravity separation could be employed underground in a narrow-vein scenario and details the test work that is required at the front-end of a project to see if this potential exists.CITATION:Murphy, B, van Zyl, J and Domingo, G, 2012. Underground preconcentration by ore sorting and coarse gravity separation, in Proceedings Narrow Vein Mining 2012 , pp 237-244 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

Elimination of zinc by the reduction of iron works dusts is examined. The process consists of blending, filtration, drying, balling, preheating and reduction in the rotary kiln. Dust slurries and dry dusts are mixed and stored in slurry basins and the blended slurry is filtered. In the balling process it is important to make green pellets which will withstand Thermal shock in the preheater and rotary kiln. Preheating to about 2000C is preferred to ensure effective use of coke fines in the blast furnace dust. The coke retained in the pellets accelerates the reduction rate. However, at the initial stage of the reduction the pellets become weakened and have to be heated slowly to prevent ring formation. In order to ensure zinc vaporization, pellets should be heated to a temperature of 1100-11500C in the kiln with injection of l ignite fines from the discharge end. Pellets having a degree of metallization of more than 90% and containing less than 0. 1% zinc have been obtained using a test kiln. The final pellet product is intended for use as blast furnace feed. A new plant with a capacity of 20, 000 tonne of dust per month is now under construct- ion and will be in operation next year.

Jan 1, 1974

By G Munro

he Melbourne City Link project will complete a missing link between two existing major freeways in the Melbourne road network, providing a much needed bypass of the Central Business District for through traffic. The project, which is being financed under a BOOT arrangement with the Victorian State Government, involves the upgrading of significant stretches of existing freeway and the construction of new sections involving viaducts and tunnels. The tunnel sections, which are the focus of this paper, are beneath residential and business areas, the Yarra River, the Royal Botanic Gardens and significant sporting facilities where surface construction would be either impossible or unacceptable (reference Figure 1). The shorter, 1.62 km west bound Domain tunnel comprises two cut and cover sections through Olympic Park then the Yarra River, the driven section of 0.68 km length and exits through a common cut and cover section with the east bound tunnel under St Kilda Road and Sturt Street. The longer 3.76 km east bound tunnel commences at the common portal, through cut and cover under St Kilda Road then 2.86 km of driven section before exiting at a cut and cover section at Burnley. The longer Burnley tunnel has an access and ventilation shaft at approximately its mid point.

Jan 1, 1999

By N Bianco, D Drinkwater

The professional skills shortage is intensifying, and commentators are predicting a shortfall in supply of qualified professionals for the mining industry, ranging from thousands to tens-of-thousands by 2020 (Tuckwell, 2011; Scoble, 2011; Laurence and Hebblewhite, 2011). Human resources are already stretched, and university graduates arriving in the workplace are often moved rapidly into management positions where there is limited scope to develop their engineering proficiency. This process may well be developing excellent young managers, but our industry is producing fewer excellent young engineers (Munro and Tilyard, 2009). Many believe that it is engineering excellence that is likely to be the key to our industryÆs success in the decade to come. An innovative in-house graduate development program has been created by specialists at the JK Centre in partnership with two mining companies. This program, known as MetSkill«, has been running throughout 2012. Groups of graduates have had to identify a process plant optimisation opportunity and embark on a structured program of data collection and analysis, facilitated by a æteaching teamÆ of researchers and consultants from the Julius Kruttschnitt Mineral Research Centre (JKMRC) and JKTech. This group project culminates in a report-back session to senior company officials. Along the way, a series of short workshops and other activities provide opportunities to work on specialist skills, and support is also offered by senior technical specialists from the companies involved.This paper outlines key features of the MetSkill« program, along with a report-card on progress in 2012 and plans for further program development in 2013.CITATION:Drinkwater, D and Bianco, N, 2012. Developing minerals industry leaders by encouraging metallurgical excellence, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 287-290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012