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By L P. Trout, D G. Reid

PanAust Limited (PanAust) has successfully constructed and commissioned two mining operations in Lao PDR over the past decade and undertaken major studies for three new mine developments. The management of potentially acid generating mine waste and tailings in close proximity of local communities sensitive to water discharge quality have been recurring themes that have confronted PanAust’s project study, development and operational teams. Further compounding challenges, such as the effects of intense annual tropical monsoonal conditions, staging of embankment raises and regular lifting of spillway structures, integrating mine waste and tailings management into production plans and ensuring the long term stability of structures, have been addressed by implementing leading practice management solutions.A recognition of the criticality of managing the substantial business risks associated with these crucial activities led to the early establishment of a governance structure to ensure that the highest standards are embraced for planning and execution. Importantly, these are guided and monitored by a panel of highly experienced and qualified international specialists reporting directly to PanAust’s Managing Director – the Tailings Independent Review Panel. The stewardship process has been effective in identifying potential shortcomings in management systems and has led to enhanced executive commitment to risk informed designs, assurance and overall process rigour.CITATION:Trout, L P and Reid, D G, 2018. PanAust Limited’s approach to mine waste and tailings stewardship, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 135–155 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The Effect of Mineral Liberation on the Floatabilities of Pyrite, Arsenopyrite and Arsenian Pyrite for Carlin Trend Ores

Sep 13, 2010

By J Guo, K Williams, S Caldwell, W Chen

Mining is increasingly occurring near or below the water table. This has led to a higher rate of handling problems associated with increased moisture and increased adhesion, which lead to a higher rate of blockage events within the materials handling chain. Typically, these ores and minerals are known as ‘wet and sticky materials’.Currently there is very limited knowledge and/or methodologies for effective design of efficient materials handling systems when it comes to handling wet and sticky materials. However, there is one major parameter that significantly affects handleability of a wet and sticky ore; namely, its moisture content. Flow property testing has shown that when moisture is reduced, the adhesive properties of the ore are also significantly reduced, thereby increasing ore flowability.The research embodied in this paper investigates the moisture reduction rate through a loose packed bed of iron ore using dry, ambient temperature airflow. A comparison of the predictive capabilities of a proposed drying model to data obtained from on-site experiments using iron ore fines is made. Building on an assumption made by Hukill (1954), a second term has been proposed to account for rewetting effects in the drying process. From this research, identification of improved moisture reduction approaches is envisaged.CITATION:Caldwell, S, Williams, K, Guo, J and Chen, W, 2017 Aeration induced moisture reduction of iron ore, in Proceedings Iron Ore 2017, pp 455–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By M Furche, U Noell, C Grissemann, J A. Meima, T Graupner, A Romero-Baena

The mining residues at the abandoned copper mine site Pe±a de Hierro, located at the headwaters of the Rio Tinto, contribute substantially to the pollution of the river with high loads of Fe, As, Pb, Zn and Cu. The pH of the outflow ranges from 0.5 to 2.4 in the dry and wet season, respectively. One heap composed of alternating layers, which were deposited parallel to the slope, was investigated in detail. Unsorted blocky to fine materials including gossan material, pyritic volcanics, ashes from pyrite combustion and slate were observed here. The top of the heap has a gentle slope and a hill contouring channel-rip morphology. The initially rugged surface was smoothed by heavy rainfalls filling up the pores of the blocky material with fines. These fines are capable of storing the water for a prolonged time, providing an extended reaction time close to surface in a dry climate at extremely low pH conditions (one to four). All minerals, pyrite, mica, barite and even quartz (probably due to F released from dissolved mica) have been digested and silica gel precipitates have formed a stable and quasi impermeable 100 ¦m layer with very low porosity (<5 area per cent, estimated using scanning electron microscopy (SEM) imaging). The silica layer itself is covered by Fe-oxy-hydroxide (ie FeOOH) coating (10 ¦m) and seals a 1 - 5 mm thick stable hardpan. This hardpan covers the channels and part of the rips almost entirely, guiding the rainwater subhorizontally towards slopes and sinkholes. By geoelectrical measurements, a 3D-resistivity model of the internal structures and the bedrock relief underlying the heap was generated. Internal structures relate to lithological changes in a number of layers. Zones of low resistivity may be attributed to washed-in fines within the mega pore system, whilst zones of high resistivity close to the surface probably reflect the advanced stage of drying beneath aging hardpans. The water movement at the surface was investigated by an artificial precipitation experiment with monitoring of the subsequent changes in resistivities.

Jan 1, 2008

Surface subsidence caused by coal mining operations was the subject of a very successful symposium organised by the Illawarra Branch of The Australasian Institute of Mining and Metallurgy in February, 1973. This symposium dealt with the principles of subsidence and overseas experiences arising out of underground mining. Since that time the New South Wales Department of Mineral Resources and Development (formerly the Department of Mines) has incorporated in the approval for pillar extraction certain conditions related to the monitoring of surface movement. Surveys and plans are required to be kept at mines where total or partial extraction of coal takes place. This paper traces the monitoring of surface movement in the Northern Coalfields of New South Wales over the past ten years. Reference is made to the National Coal Board's Subsidence Engineers' Handbook (1975) and how the guidelines expressed therein have been beneficial. Mining engineers in Australia are able to plan underground workings where minimum subsidence is allowable and are in a position to foreshadow the surface effects where total pillar extraction is carried out. In certain cases such surface effects can be minimised by structural design in buildings or pipelines.

Jan 1, 1980

By P Lindsay, J B. Hughes

Underground and opencast coal mining has been ongoing since 1896 on the Stockton Plateau, West Coast, New Zealand. Acid Rock Drainage (ARD) from historic and current mine workings has had an adverse environmental impact on the surrounding aquatic environment. The two main catchments affected by ARD are those of the Mangatini and St Patrick streams. These catchments flow into the Lower Ngakawau River, which holds high amenity value for the local community. Water quality targets set by Solid Energy for 2010 in the Ngakawau River include increased pH and clarity and a decrease in certain dissolved metals.   At-source ARD minimisation options are the first stage in mitigating the effects of mining acid forming rocks and reducing acid loads in the Mangatini and St Patrick stream catchments. ARD minimisation techniques reduce the quantity of acidity generated and thus reduces the treatment required. Treatment will be required for many years at Stockton due to current and historical acid formation. This paper looks at the treatment options that Solid Energy has been investigating including limestone leach beds, engineered wetlands, oxic limestone drains, and limestone dosing of catchment drainage. Particular focus is given to fine limestone dosing of the Mangatini stream and subsequent water quality improvements.

Jan 1, 2007

By J Samosir, L Snyman

Northparkes was the first mine in Australia to use block cave mining method which relies on gravity and natural rock stresses to fragment and recover the ore. It was also the first hard rock mine to use hydraulic fracturing, in conjunction with CSIRO, to promote caving of E26 Lift 1. The technique was later used on E26 Lift 2 wedge and E48 prior to undercutting.Northparkes production is currently sourced from the E48 Lift 1 block cave mine and E26SLC. The E48 block cave contains economic ore to the north and south of the current cave footprint. To recover this ore the footprint has been extended on the north and south with two extraction drives and one extraction drive, respectively. Modelling of cavability above the additional drives indicated that the cave would not readily propagate to a sufficient height of draw to mobilise the ore and tended to arch over into the existing cave. To address the modelling results and to reduce the risk of the project, rock mass preconditioning was adopted.This fracturing campaign was performed from surface drill holes adjacent the subsidence zone angled to intersect the higher grade and higher elevation ore zones.Optical televiewer surveys, run prior to fracturing, picked intervals and fault zones to be avoided. Holes were resurveyed post-fracturing to detect newly created fractures and as a measure of success of the program.During fracturing operations water and gel fractures were run at varying depths and pumping pressure was logged for each fracture. The mine seismic system monitored significant events and dye in the fluids utilised for tracking water inflow locations during underground inspections.Towards the end of the project, guar fibres from gel were detected within the mill circuit and required treatment to resume optimum processing.CITATION:Webster, S, Snyman, L and Samosir, J, 2016. Preconditioning E48 cave extension adjacent to an active cave, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 471–478 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The history of mining is rightly proud of its achievements in improving productivity and cost improvements over the years. No matter what measure is used, tonnes per manhour, cost per tonne, etc vast improvements have been made over the last hundred years. In fact over the last ten years in Australian coal mines raw coal output per employee has increased by 60 per cent. When one examines why these improvements have taken place the principal reasons have been technological advancement in mining equipment, excavator and dump truck capacity increases, longwall and continuous miners continually improving in reliability and size. Of course all these improvements are correlated to an increase in capital cost. Even with the above-mentioned advances the pressure for increased performance is as strong as ever. The international mining and mineral-processing sector is currently operating in a recessive market with some traditional commodities, eg gold trading at 20 year lows. During recessive times senior management will demand greater returns on capital employed: the obvious choices being reducing costs or increasing throughput. In addition, head office environments will often place a capital freeze on operational management so the opportunity to take advantage of technological change is not available. The challenge is, therefore, to increase throughput and cut costs without the need for capital. The answer is to optimise the existing labour and plant. If done systematically a result in productivity improvement, in our experience, as high as 45 per cent can be achieved with the average across South East Asia and Australasia being 21 - 23 per cent. The intention of this paper is to present a systematic approach to labour and machine utilisation thereby gaining the greatest possible return on the existing capital base.

Jan 1, 1999

The Performance of Benzyl Arsonic Acid as a Collector in the Flotation of Wolframite and Cassiterite Slime

Sep 13, 2010

By D Pastars, J L. Mauk

Located at the southern end of the Awhitu Peninsula, the Waikato North Head ironsand mine is approximately 50 km southwest of Auckland . The ironsand deposit consists of Quaternary sands, clays and peats, formed by aeolian and marine processes. We sampled on widely- and closely-spaced intervals to test variability within the mining area. X-Ray powder diffraction shows that samples contain feldspars, quartz, pyroxenes, amphiboles, clays and titanomagnetite. Densities range from 1.6 to 2.5 grams/cubic centimetre, with porosities from 30 to 43 percent. The percentage of magnetic minerals values range from 0 to 75 percent, slimes (clay minerals) values of 0 to 26 percent and non-magnetic minerals from 20 to 95 percent. Mineralogical differences in the Mitiwai Formation and Waiuku Blacksand Member cause bimodal populations in the density, magnetic minerals, nonmagnetic minerals and slimes plots. The Mitiwai Formation has higher non-magnetic mineral values and lower density, slimes and magnetic mineral values than the Waiuku Blacksand Member.

Jan 1, 2001

Perception has the unfortunate habit of becoming reality. Urban inhabitants unfortunately do not regard mining as a legitimate or desirable business, despite its contribution to Australia's export income (+A $8,000 million, being nearly a third of all exports); share of GDP (it is 4.5%); and the fact that its presence fills up all the empty spaces northwest of the Adelaide-Melbourne-Sydney-Brisbane crescent of inhabitation. The huge economic contribution of Australia's minerals industry, resulting from providing more than half of merchandise exports (Figure 1), is achieved by employing only some 2% of the national work force (Gaulton, 1997). Unfortunately, the minerals industry's critics generally oppose exploration on the basis that what you don't know will not hurt you. It is the 'do-not-confuse-me-with-facts' philosophy or 'ostrich syndrome', which somehow crudely assumes that mining practices have stayed in the style popular circa late 1800s. Somehow ignorance really is bliss for these idealistic believers, who are reminiscent of the members of the Flat Earth Society!

Jan 1, 1997

By G Ma, L Qi, J G. Shellnutt

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Emeishan large igneous province (ELIP) of SW China is host to magmatic Ni–Cu–(PGE) sulfide and Fe–Ti–V oxide deposits which contain economic to subeconomic concentrations of precious and base metals. The formation of a given deposit-type (ie sulfide versus oxide) is thought to be related to the type of parental magma (ie high-Ti versus low-Ti) and the subsequent processes (ie fractional crystallisation and sulfide segregation), which allowed for metal enrichment.We examined the PGE of Baima and Taihe oxide-bearing layered mafic intrusions from the ELIP (Shellnutt, Ma and Qi, in press), and compared them with the nearby Xinjie and Hongge intrusions as well as with the Emeishan flood basalts. The PGE results for the two intrusions are contrasting. The Baima gabbroic rocks are almost PGE-barren (SPGE < 4 ppb) whereas the Taihe gabbroic rocks are variable, but generally much higher in PGE concentrations (SPGE < 2 to ~300 ppb), although the gabbros from both intrusions are enriched in platinum-subgroup PGE (PPGE = Rh, Pt and Pd) relative to iridium-subgroup PGE (IPGE = Os, Ir and Ru). Cu/Zr, Ni/Ir, Y/Pt, Cu/Pd and Ni/Ir systematics suggest that the Baima rocks were derived from a relatively evolved, mafic, S-undersaturated parental magma that was affected by earlier sulfide segregation. In contrast, the Taihe rocks record evidence of both S-saturated and S-undersaturated conditions and that the parental magma was likely emplaced very close to S-saturation. Through comparison of the PGE contents in the Emeishan flood basalts and the Emeishan oxide-bearing intrusions, we provide a self-consistent model for ELIP that the PGE budget in a magma is not strictly controlled by magma series (high-Ti versus low-Ti), but very much by crustal contamination.CITATION:Ma, G, Shellnutt, J G and Qi, L, 2015. Platinum group elements in the Baima and Taihe Fe-Ti oxide-bearing gabbroic intrusions of emeishan large igneous province and problems on propensity of magma series for sulfide- versus oxide-dominated deposit types, in Proceedings PACRIM 2015 Congress, pp 303–310 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A Goldstone, T Maton

The Golden Cross Mine is located on the North Island of New Zealand, at the base of the Coromandel Peninsula, approximately 8 km northwest of Waihi. The project is operated as a Joint Venture with Coeur Gold New Zealand holding 800/0 and Viking Mining Limited with a 20% interest. The past open-pit and underground gold and silver producer has been in the reclamation phase of the operation for approximately 2.5 years and is now nearing completion. Although rehabilitation of the site is a regulatory requirement, the Closure Plan has been enhanced by the ongoing commitment of the Joint Venture to establish a sustainable land use for the site by commissioning engineered facilities designed to last for perpetuity. The Joint Venture identified six significant design features that were key to successful rehabilitation. These were the controlled placement of acid generating waste rock into engineered disposal sites; the design and placement of sealing layers over the waste rock disposal sites; the design and construction of diversion drains; the establishment and management of vegetation to protect the oxygen diffusion layer; a partial capping of the tailings to accelerate consolidation adjacent to the tailings dam embankment, and the implementation of a cyanide recovery circuit to recycle cyanide from the tailings prior to disposal. Another key to success for the project involved genuine consultation with all parties participating in the planning, evaluation, and consenting of the closure process at Golden Cross. The local and regulatory community has been widely represented in the Joint Venture's operating and closure plans throughout the history of the mine. Participants include: Regional and District Councillors and staff members, professional peer reviewers, environmental groups, local residents of the valley, and Iwi. This overall commitment to the project has resulted in a world-class rehabilitation program for the first modern metal-mine closure in New Zealand and we believe that collectively, the work done at Golden Cross is helping to set a standard for the success of future programs within the extractive industry.

Jan 1, 2000

The Johnny Mercer lyrics 'You've got to accentuate the positive, Eliminate the negative, Latch on to the affirmative à' would best sum up the traditional approach to community relations in the mining industry. This '90s 'Public Relations spin' approach, usually backed up by scientific data, technical reports and graphs outlining risk probability and the impact potential on people and communities, is being challenged. Challenged by communities who have greater access to information, demand greater levels of transparency and corporate responsibility of large corporate operations and possess greater awareness of the communities they live in.   The growth of the environmental movement, of anti-globalisation, anti corporatism, apprehension of a large corporate's ability to deal with community issues, and a lack of faith in the abilities of regulators to regulate corporate activities, means our industry faces challenges on multiple fronts. It must now be able to address these from a personal/community perspective if it is to remain relevant within communities.   One of the keys to this is linking the internal activities and responsibilities to the externals concerns and demands for higher levels of operation and care.   This presentation draws on Corporate Public Affairs trends, functions and approaches and the application to External Affairs activities within Newmont Waihi Gold's operations in Waihi and regional exploration activities throughout the Hauraki Goldfields.   The approach presented works on the philosophy that communities don't necessarily have to like what we do, but should be able to identify and recognise the way in which we involve them in decision making, communicate our intentions and respond to issues.

Jun 1, 2010

Au-Ag Recovery from Complex Ore by Flotation

Sep 13, 2010

By B Kilgariff

Flotation has been in use at Broken Hill for nearly 100 years, and the process has gone through many different optimisation studies over that time. This paper reviews the current flotation practice at the Perilya Broken Hill Mine, and details one of the recent optimisation studies conducted using mathematical modelling and simulation tools. The optimisation study consisted of surveys of the lead and zinc circuits, mapping of the floatability components of the ore and developing models of the lead and zinc circuits. The models were then used to conduct simulations to simplify the circuit. The study allowed plant personnel to identify optimum operating conditions for their current flotation cells, as well as possible improvements in circuit configuration and cell capacity.

Jan 1, 2005

Separation of Iron Particles from Banded Haematite Quartzite (BHQ) Ore by Selective Magnetic Coating The separation of fine iron particles from banded hematite quartzite (BHQ) has been studied using selective magnetic coating. The BHQ ore assays as 38.9 per cent Fe, 42.5 per cent SiO2 and 1.0 per cent Al2O3. Mineralogically, the ore contains hematite and quartz as the major mineral phases where as goethite and magnetite is present in minor entities. Natural magnetite of very fine size and oleate-magnetite in colloidal form, prepared synthetically in the laboratory are used as the coating material on the surface of hematite particles. The selective coatings of oleate-magnetite on BHQ surfaces followed by magnetic separation studies have indicated that, it is possible to achieve 62.3 per cent Fe with 8.5 per cent SiO2 at 85.4 per cent iron recovery. The recovery of iron values is found to be superior in comparison to the conventional magnetic separation techniques. The selectivity of coating for enhancing the magnetic response of iron particles is achieved by controlling the surface properties of the particle via electrokinetic potential adjustment by controling pH and addition of oleate-magnetite. In the separation process, the effects of pH, magnetic intensity and addition of oleate-magnetite are studied to achieve the maximum grade and recovery of iron values. The optimum separation is observed at pH of 7.5, oleate-magnetite concentration of 0.25 ml/g of BHQ ore and a magnetic intensity of around 0.8 Tesla. The X-ray diffraction (XRD), Infra-red spectroscopy (IR) and UV-visible spectroscopic studies strongly suggest preferential coating of magnetite on hematite surfaces. Scanning electron microscopy (SEM) studies have brought out the semi-quantitative features of BHQ ore. The recovery of iron values from a lean grade ore such as BHQ is carried out looking into the future needs of this ore in India for iron and steel making.

Sep 13, 2010

By D Craw, S Clearwater, S Hammit, C Smith

Prior to rehabilitation, plant cover on quartz gravel overburden at Wangaloa coal mine was highly patchy. Stabilisation techniques have since considerably altered the condition of the main overburden yet deposits in the east and west remain largely intact. On the eastern overburden, three distinct zones of revegetation have naturally developed: Zone 1 represents a dense plant cover, Zone 2 a patchy cover and Zone 3 a sparse cover of isolated plants. Aerial photographs show much of the eastern overburden was deposited between 1940 and 1960s. Yet we found that the temporal scale of deposition did not wholly account for the differences observed in vegetation development. To investigate other influential factors, we set up 12 study plots using four replicates in each vegetation zone. The diversity and density of plants in each plot were measured to quantify the degree of vegetation development. Samples from the substrate in each plot were collected using soil cores to a depth of 10 cm. Cores were analysed for indicators of nutrient availability, metal content and physical composition. We found that substrate chemistry varied between individual study plots, but showed little difference overall along the vegetation gradient. Substrate physical differences were much greater. The ratio of coarse quartz pebbles: fines was considerably higher in Zone 3 than other zones, and within zones where plants were not growing. Bulk density also increased successively from Zone 1 - 3. We found clear evidence for the reversed stratigraphy of excavation superimposed over the time scale of deposition, and the corresponding nature of fine particles. The rate of revegetation was therefore highly dependent upon the substrate composition of the last surface deposit from the dumping truck. Our data suggests an optimum ratio exists between inert coarse material and a fine matrix for progressive natural vegetation development on mine substrates.

Jan 1, 2004

By J S-L Chan

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Cu-Ag-Au mineralisation at Kluwih prospect in Eastern Java, Indonesia is related to a high-sulfidation hydrothermal system within a volcanic dome (2.35 × 1.7 km diameter). The mineralisation occurs mainly in steeply dipping, structurally-controlled quartz-enargite-pyrite veins (several centimetres to 2 m wide) and is hosted mainly in porphyritic dacite, volcaniclastic rocks and volcanic breccia of the dome and in an underlying andesite that yielded a zircon U-Pb age of 11.5 Ma.Short wave infrared spectrometer analyses were carried out for alteration mapping at Kluwih. There are two main stages of alteration produced by the hydrothermal activity. The alteration mineral assemblages indicate an advanced argillic alteration. The Cu mineralisation occurred in the form of enargite and subordinate chalcopyrite with an intergrown texture in the early stage. These mineralised veins are characterised by narrow pyrophyllite ± diaspore and dickite selvages (metres wide) and a peripheral K-muscovite envelope (sericitic alteration) up to 100 m wide. The K-muscovite envelope is zoned outward to Na-muscovite or Na-illite. Late-stage kaolinite and smectite alteration overprints the porphyritic dacite and may obscure the nature of early mica-clay alteration. The spatial distribution of different alteration assemblages suggests that the temperature of hydrothermal fluid increases with depth.Both the high-sulfidation mineralisation and advanced argillic alteration are suggested to be related to magmatic-hydrothermal fluids, which are likely to originate from an undiscovered deeper porphyry Cu-Au system below the porphyritic dacite. Based on alteration mapping results and comparisons to similar deposits, the porphyry intrusion could be up to 500 m below the volcanic dome. Further geochemical and mineralogical studies may help to target the potential underlying porphyry system.CITATION:Chan, J S-L, 2015. High-sulfidation epithermal Cu-Ag-Au deposit, Kluwih, eastern Java, Indonesia – alteration and implications for potential porphyry cu mineralisation, in Proceedings PACRIM 2015 Congress, pp 213–218 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

CrusherMapperTM - A New Tool for Crusher Condition Monitoring The efficiency of mineral processing plants is entirely dependent on the availability of the plant equipment critical path. This typically concerns comminution circuits consisting of primary crushers and primary grinding mills. Crusher and mill availability are determined by the frequency and duration of maintenance shutdowns, which are primarily driven by the need for replacement of sacrificial liners. The change of crusher and mill liner shape over respective life cycles also strongly affects plant efficiency. It is therefore highly desirable to accurately monitor the condition of mills and crushers in order to optimise plant efficiency through maximised availability and targeted liner shape. Traditional comminution liner and other production parameter condition monitoring has been attempted through ineffective methods which prevent satisfactory management of crusher and mill maintenance and reduce operational control. This situation has recently dramatically improved for grinding mills through the development and commercial deployment of MillMapperÖ, a technology based on three-dimensional laser scanning data and dedicated software (Franke, Lichti and Stewart, 2006; Franke and Lichti, 2007; 2008; Franke, 2008; Franke, Redman, Johnson and Michalek, 2009). At the time of writing in late 2009, MillMapperÖ is in successful use at a rate of approximately 170 surveys and associated reports per annum at processing plants in Australasia, South America, North America and Africa. This paper presents the introduction of CrusherMapperÖ, the MillMapperÖ equivalent for crushers. CrusherMapperÖ also utilises high density, high accuracy laser scanning data, and features dedicated algorithms for three-dimensional monitoring of wear on crusher concaves and mantles. This facilitates the detection of wear hot spots or zones or localised liner failures, and accurate forecasting of reline tonnages and dates. It also for the first time provides the means to establish optimised concave and mantle shapes in order to achieve production targets. In contrast to any other currently utilised condition monitoring method, CrusherMapperÖ data collection can occur remotely and does not require any shutdown or crusher isolation. This method therefore does not interrupt crusher production while at the same time eliminating any confined space risk normally associated with taking measurements inside the crusher cavity.

Sep 13, 2010