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Gold mineralization belt of eastern China in the adjacent part of the northwestern Pacific rim is orientated NE to NNE and as-sociated with Mesozoic faults and igneous intrusives and Mesozoic to Cenozoic volcanism and subvolcanism extending more than 3000 km in length and 300 to 800 kni in width affected by the movement from the Pacific Plate subducted against the Asian Plate.The relative movement between the Pacific and the Asian plates give rise to two types of fracture zones, the tensional ones providing the space for the formation of fissure-filling type of auriferous quartz veins and the shear zones providing the space for the formation of hydrothermal replacement type of gold de-posits in Shandong Peninsula. The fissure filling type of quartz vein, is represented by Linglong gold deposit which is hosted in Mesozoic Linglong Granite and consists of hundreds of quartz veins filling fractures trending NE to NNE and the hydrothermal replacement type is represented by Sanshandao gold deposit which is hosted in crushed and hydrothermally altered Mesozoic Linglong Granite in contact with Archaean metamorphic complex of Jiaodong Group along a Mesozoic upthust fault zone trending NE.

Jan 1, 1990

The exploration and mining risks are investigated and compared to the risks of smelting, secondary processing and other normal industrial activities. This study concentrates on the risk before, or at the investment decision. Internal and external risks are distinguished. Internal risks are the risks inherent in every engineering design and common to all projects. The main external risks are the financial risk, changes in prices, location problems and geological factors. Financial risks concern every capital-intensive and export-oriented project and cannot be considered as typical mining risks. Changes in prices, i.e. the market risk, concern every industry using raw materials, but the market risk is especially accentuated in the mining industry. Problems of location and infrastructure are normally more significant in mining than in other projects, and geological risks are unique to mining. All these risks associated with mining projects combine to form a risk at least twice as high as that for other normal industrial activities. Within the range of profitability of mines, which on average is the same as in the manufacturing industry, only a few highly profitable mines exist. These few mines are the sole reward for the high risks taken.

Jan 1, 1986

By A J. Moore

Predictive assessment of surface blast vibration requires the identification and quantification of significant factors, and the summation of their combined effect. Methods available for the prediction of significant factors are described, and examples are given of the combined use of these methods to evaluate alternative proposals.

Jan 1, 1999

By S La Brooy, C Fountain

Throughout its history the mining industry has focused on the highest-grade deposits sited in the most convenient locations. The burgeoning global population and higher standards of living not only increase the demand for mineral products but also make it harder to mine and process them. The future will include the development of lower-grade, more complex orebodies, and orebodies in difficult locations. The industry will be expected to provide for humanityÆs needs while reducing its environmental footprint and maintaining profitability. This paper reviews some of the likely adaptations in mineral processing that will occur over the next 20 years. The challenges inherent in adapting to lower grade and more complex materials might be exacerbated by such factors as the availability of water and low-cost energy. In underground mining, higher energy costs are likely to foster further developments in underground preconcentration, especially for ores that can be upgraded at relatively coarse sizes. The adoption of underground crushing could also render material amenable to semi-dry preconcentration options such as might be achieved by the rotary classifier developed by CSIRO and being commercialised by RCR Tomlinson, or more modern versions of the hand-sorting of ore that use sensors based on colour or other suitable rock properties. The cement industry and some gold roasters have used the alternative of dry grinding and classification, which might also have a part to play in dry processing. There is also likely to be increased interest in options such as in situ leaching that further minimise the surface disturbance. Underground operations will have to balance the energy savings from reducing the amount of material brought to the surface and reduced surface disturbance against the practical limitations of installing and maintaining processing equipment underground. On the other hand, surface disturbance and energy issues in open cut operations will be balanced by potentially lower mining costs and higher overall recovery from the deposit.

Jan 1, 2008

By A Buckingham, R M. Hancock

The underground Sunrise Dam gold mine commenced in October 2003 to extract ore from a series of orebodies with various dips, widths, and ore grades over a strike length of 1.5 km. To successfully operate flat stopes it was identified that a means to extract ore left behind after blasting in stopes with dips ranging from 15 to 40 degrees was needed. Various options were available, which included a bulk water cannon, hand held high-pressure water jet, remote controlled small dozer, several mini excavators and finally a specialised remote controlled excavator from the demolition industry. Trials were commenced for the bulk water cannon option in 2006 that proved that the concept worked, however, the system was too cumbersome to set up for use in cycle with production. Hand washing down using mine (low pressure) water with a two-inch bullhose proved of limited value. The small, one metre high remote controlled dozer as used in South Africa was reviewed, but the steepness of most of the stopes precluded this machine. The hand held high-pressure water jet option is still being investigated; with safety factors still being addressed. Several mini excavators were trialled to clean out the flat stopes with generally poor results, the machines being either too large to fit in the drives and pull ore down or too small with too short reach to effectively and efficiently pull ore out of the stope. In early 2007 a Brokk 330 remote controlled excavator was trialled on site with the low profile of the machine and unique arm configuration proving an effective tool for pulling ore from the footwall of short, flat stopes. A Brokk 330 remote controlled excavator was purchased in late 2007 and is currently in operation.

Jan 1, 2008

By Lewis IE

Copper-lead dross is a by-product of the refining of lead bullion produced by the Imper- ial Smelting Process. This dross contains some 27 percent copper, 50 percent lead, four percent zinc and one percent sulphur. An ammonium carb- onate leach at atmospheric temperature and pressure removed the copper from the dross while the lead zinc and precious metals remained in the leach residue for return to the smelter. The leach solution containing the copper was then purified by liquid-liquid ion exchange using LIX64N in a kerosene diluent. ("LIX" is the registered trade mark of a range of hydroxy oximes marketed by General Mills Inc.) The pilot plant had a capacity of 0.7 kg/h of CuSO4,5H20 and was operated for some fifty days on a two shift basis. Copper sulphate of excellent purity was produced, and the results obtained indicated that a copper recovery of ninety percent from the dross could be expected from a commercial installation.

Jan 1, 1975

A sample of tailings from a local, low grade (less than 2g/t) tailings dump was investigated for gold recovery. The tailings were very fine, with 90 per cent passing 30¦m and almost 60 per cent passing 10¦m. Tabling the coarse product from classification using a cyclone proved unsuccessful, with low recoveries being obtained due to high gold losses in the slime streams. Gold recovery by cyanide leaching was quite rapid, with recoveries of 85-90% being obtained in five hours. Lime and cyanide consumptions were 3 g/t and 0.1 kg/t respectively. Gold loading onto carbon was inhbited by the presence of the large amount of fines, so heap and vat leaching should be considered where the gold is recovered from a clear pregnant solution. Settling tests were conducted on tailings. It was observed that the addition of at least 3 kg/t lime or 0.4 kgh nonionic flocculant was necessary to promote settling of the tailings to generate a clear supernatant for gold and water recovery.

Jan 1, 1991

By D Curry, M F. Young

æConventional wisdomÆ believes that fine particles have low flotation recoveries. Plant size û recovery graphs often have the classic æhillÆ shape û high recovery in the mid sizes and low recovery at the fine and coarse ends. Yet if mineral liberation is poor, low fines recovery may be because you don't grind fine enough! This apparent paradox is explained by the old concept of æsand/slimesÆ circuits, which recognises the different flotation needs of fine and coarse particles. This concept is overlooked in the push for simpler circuits and larger equipment. Most plants now treat all particles together in a wide size-distribution. Reagent conditions are set for the dominant coarser particles, so fines are starved of collector. Worse still if there are significant midsized composites û often these have to be rejected in cleaning to achieve target concentrate grade. But the conditions which reject mid-size composites û collector starvation and high depressants û also reject fine liberated particles. In fact, fines flotation can be excellent when flotation chemistry is tailored to fines.

Jan 1, 2004

Blasting effectiveness must be gauged by total production costs. ANFO charges made up in polythene "sausages" are not as profitable as is indicated by the price of ANFO. All-slurry charges are warranted only where blastholes cannot be dewatered effectively, or where drilling costs are very high. An increase in blasthole diameter leads to coarser fragmentation. This effect is most pronounced in tough and massive or blocky strata, or in ground which consists of unfissured boulders in a softer matrix. When ANFO and some slurry-type charges of small diameter are used in plastic-acting ground, charges may fail to detonate through precompression by charges fired on an earlier delay. The optimum blasthole length is rarely less than four times the burden distance. For best results, blastholes should be inclined to the vertical and parallel to the face. Nominal burdens and spacings are often altered radically by the initiation sequence. For best fragmentation, all blastholes must have good effective faces, and should be effectively stagg- ered with an actual spacing:burden ratio in the approximate range 2.0-5.0.

Jan 1, 1975

The word governing derives from gubernare meaningto pilot a ship. Being inclined to metaphors, one could be forgiven to think that politicians act this verb and captain the Nation's ship into some definite course. In the case of at least the mineral resources industry, it seems that there are not many James Cook followers in our parliaments: Australia's approach to mineral and energy policy is often chaotic - witness the 1935 to 1961 ban on iron ore export-ing which prevented the development of a significant steel industry at time when the World was hungry for this metal, just to mention one amongst many other examples.The follies of Australia's mineral policies are well il-lustrated in the case of uranium mining. Although Australia had the Western World's largest economic reserves of uranium, it is onlythefifth producing nation and its uranium potential is largely unrealised. At the root of this situation are the interventionist attitudes and policies of successive Federal Governments which for more than four decades distorted the Investment decision and, in more recent times. discouraaed investment.

Jan 1, 1990

By G J. Sparrow, M J. Fisher-White

A mineral and chemical characterisation study was conducted on ilmenite-rich heavy mineral concentrates sourced from the western sector of the Eucla Basin in southern Australia. Test work involved using X-ray diffraction (XRD), scanning electron microscope (SEM) and electron microprobe-based characterisation methods. Results showed considerable variability in the degree of ilmenite alteration between deposits with TiO2 contents varying from 53 - 63 wt per cent TiO2. Notwithstanding variability between individual deposits, the samples all had [Ti]/[Ti+Fe] ratios >0.5 consistent with a mineral assemblage of hydrated ilmenite or the hydrated, Ti-rich alteration phase pseudorutile (Fe3+2-x Ti3O9-3x (OH)3x). Accessory phases consisted of rutile (primary and secondary), zircon, aluminosilicates, quartz, Fe oxyhydroxides and spinels. Results for the most altered material are broadly comparable with data for ilmenite concentrates from the eastern margin of the basin. The mineralogy of the western Eucla Basin concentrates and the minor element composition of the ilmenite grains suggest they could be upgraded to synthetic rutile by a modified Becher process.

Jan 1, 2008

By Muir D

A review of the various methods of degrad- ing cyanide either from gold processing liquors or electroplating baths is presented with some discussion on their relative merits or problems. Whilst alkaline chlorination is common practice in many U.S. and Canadian plants it poses particular problems for certain plants. Alter- native methods include electrolysis, hydrolysis and air oxidation with activated carbon as catalyst which are also integral steps in the carbon-in-pulp process. A basic study of the degradation of cyanide ion has been carried out therefore to determine the effect of temperature, oxygen and carbon. It is shown that carbon is an excellent catalyst for degradation by air and likely to lead to higher losses of cyanide in a C.I.L. circuit. Degradation by hydrolysis is important at high temperatures and high pH such as employed in the Pressure Zadra or Anglo elution processes. Carbon catalysed degradation of cyanide by oxygen in effluent streams may be an environmentally acceptable alternative to conventional chlorine degradation.

Jan 1, 1987

By S C. Goel

The Obuasi Mine in Ghana, West Africa is the largest producing gold mine in Africa, outside South Africa. The mine has changed from a mine producing from narrow vein, high grade quartz orebodies to a mine producing from wide, lower grade sulphide rebodies. Traditionally mining methods were cut and fill and sublevel caving. Now the preferred stoping methodologyis long hole open stoping. Transverse or longitudinal methods are both used, dependent on the orebody characteristics. The change has been technically, socially, economically and politicallychallenging and at times has tested the abilities of those responsible for the operation of the mine. However, the benefits have been many. Safety has improved significantly, ounces from underground have doubled. Productivityhas doubled and underground unit costs have reduced bya third. These achievements have allowed the Obuasi mine to staycompetiti ve in this time of falling gold price. During 1999 and 2000 a full review of the mining and processing operations was undertaken, and as a result, the mine is now in a phase of restructure. Efforts are being made across the mine to improve efficiencies and to reduce costs. The future for the Obuasi Mine is an exciting one.

Jan 1, 2000

By Daxian Z, Youdi Z, Shucai Y

The Huolinhe surface mine is a very large-scale surface coal mine, located in the north-east area of China with a production rate of 1.2 Mtpa. Its coal haulage system has a large capacity, long transportation line and high degree of automation. The system comprises two crushing plants, many belt conveyors, four surge bunkers, one loading bunker, one coal storage and five end product bunkers. In this paper, the network patterns of semi-continuous systems in surface mines are studied, the reliability calculation methods and a simulation model are established and the software for computing the reliability of a semi-continuous system is worked out. By considering the whole coal haulage system in the Huolinhe surface mine, the authors developed the system reliability-numerical simulation method. The steps and the computing results of this method are described in detail. Through the calculation, we can master the present situation of system reliability and the main factors impairing system reliability, expose the system weak links, put forward the ways of enhancing system reliability and furnish the basis for improving the system and equipment. The way of increasing capacity and methods of enhancing system reliability are further raised.

Jan 1, 1995

By P M. Downes

Porphyry-related skarns are common around thePacific Rim. Examples include Cadia and Goonumbla (Australia) Ok Tedi (PNG) and Ertsberg and Grasberg (Indonesia). Although usually treated as separate to the adjacent porphyry copper-gold (Cu-Au) deposit, skarns near porphyry deposits are commonly inextricably part of the larger Cu-Au system(s). Using Cadia as the primary example, we demonstrate that large, zoned, calc-silicate skarns necessitate very large porphyry systems. The Big Cadia and Little Cadia Fe-Cu-Au skarns are associated with the Late Ordovician to Early Silurian high-K calc-alkaline to shoshonitic Cadia Intrusive Complex (CIC). Together, these skarns total ~40 Mt of Cu-Au ore but are much smaller than the adjacent Cadia EastûFar East, Cadia Hill, and Ridgeway porphyry-related Cu-Au deposits. Historically these skarns were large, economically significant and highly controversial deposits. Porphyry-related skarns typically have well-developed calc-silicate and ore zonation. At Cadia, classic skarn zonation has been mapped between Cadia Quarry (proximal) and Big Cadia (distal). Over this 800 minterval, mineralogy trends from: proximal garnet > pyroxene, grading to; fe-oxide-rich skarn; and distal haematite-epidote-rich skarn. At Little Cadia, analogous but symmetrical alteration zonation is present. Big Cadia formed from fluids that migrated laterally within calcareous units and were sourced from strongly altered quartz monzonite phases of the CIC at Cadia Quarry. Isotope studies and mass-balance calculations suggest that prograde and retrograde skarn alteration was caused by magmatic dominated fluids. They also indicate that the mapped alteration system at Cadia Quarry is insufficient to account for the total volume of Fe present at Big Cadia. Despite the typically oxidised nature of many porphyry systems, not all skarns in the porphyry environment are oxidised. Assimilation of carbonaceous sediment by hydrous, alkaline intrusions could lead to reduced Au skarns rather than porphyry deposits. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By V S. Svinin, V V. Rybin, V A. Maltsev

In large-scale mining, large-sized intermediate pillars, or block-pillars, are generated on the horizon or between closely located mines. These pillars are mined under high rock pressure that results from the stress concentration zones superposition from closely located working excavations. This problem becomes much more complicated if high tectonic stresses occur in the rock mass inducing a rock-burst risk situation. Mining experience gained in mining seven block-pillars at three Khibiny mines in Russia under the geomechanical situation like that described aboveÆ is discussed in detail. It has been shown how safe mine of block-pillars depends on their width, location relative to significant geological failures and uncaved rocks of the hanging wall, the order of pillar recovery, and application of special measures for rock mass stress relieving. Basing on the analysis of the mining experience and special scientific researches, the basic principles are worked-out for safe block-pillar mining under rock-burst prone conditions.

Jan 1, 2000

The Century zinc-lead orebody was discovered in 1990 and contains sufficient reserves to sustain open cut mining at 5 Mtpa of ore for approximately 20 years. It is proposed to pipe mineral concentrate in slurry form 300 km from the mine to the port of Karumba on the Gulf of Carpentaria. The concentrate will be dewatered at Karumba before being transported off-shore to deeper water in a self-unloading shuttle vessel for transfer to export bulk carriers. The four main environmental issues that attracted attention during the impact assessment phase of the project were: the selection of Karumba as the export port, the use of a pipeline to transport concentrate, the risk of concentrate spillage in the marine environment, and aquifer drawdown in the vicinity of the mine. This paper discusses these issues with emphasis on the context of the relationship between the Pasminco Century Project and Gulf communities. Environmental safeguards are discussed, including those that arose out of the negotiations regarding Aboriginal native title.

Jan 1, 1998

This brief overview of the history of Brown Coal mining in Victoria is a luncheon presentation -I do not intend to make it indigestible with extensive listings of resources or production. There is a vast pantry of collated historical records and of vari- ous predictive studies available for the enquired with a hearty digestion. A gourmet collation is provided in The Aus IMM Monograph No 11 published in 1984 entitled "Victoria's Brown Coal-A HUGE FORTUNE IN CHANCERY", currently still on offer by the Institute and available at a bargain price in the foyer at this conference. Monograph No 11 also provides a feast of excellent references on the theme of Victorian Brown Coal assembled by the several contributors. In contrast, my presentation paper is a fast-food service, extracts from the printed paper only-you have no choice-you "get what you get" and in small quantity. I hope it will tantalise your appetite -like Oliver Twist you will ask for more. -Buy the Monograph!

Jan 1, 1989

By Canterford J. H, Bologiannis F, Smith A. N

The Mutooroo copper mine is one of a number of deposits that have been evaluated by Adelaide and Wallaroo Fertilizers Ltd as a source of feed for the production of high- purity copper oxide at their Burra plant. For this deposit, the technique of solution mining or in-situ leaching appeared ideal. The Mutooroo production circuit and the results of the process optimization and environmental monitoring programmes are outlined. At the end of the experimental period described here, the production liquor typically contained I g/litre copper, yield- ing in excess of 5 t/month of cement product containing about 80 per cent copper. The environmental monitoring programme provided clear evidence that there had been no un- acceptable alteration to the properties of the groundwater in the country rock surround- ing the mineralized zone. It is anticipated that the experience gained at Mutooroo will be of considerable help in the development of other solution mining operations.

Jan 1, 1983

By Kim YC

An alternative development drilling strategy to the one currently in use at an open pit mine was investigated using geostatistics for a portion of the pit. The massive orebody, the 3-D nature of the problem, and the location of ultimate pit limit in the study area all created some unique problems in devising the development drilling strategy. Rather than using confidence interval of the global reserve estimate as the main criterion for development drilling, the confidence interval of short and medium range mine planning blocks was used as the objective. Based on somewhat arbitrarily selected level of confidence, the results from the study showed that a total of 50 diamond drillholes (DDHs) rather than the planned 62 DDHs is sufficient in the study area, if the selected confidence levels are acceptable to the management. The paper also emphasizes the importance of particular objectives being used in development drilling and how they influence the "optimal" placement of the development drillholes.

Jan 1, 1986