Dust emissions are an environmental issue of increasing concern to both government regulators and the community. The main concerns relate to potential amenity, and health and environmental impacts from the emissions. It is therefore imperative that mining/processing operations, as part of their overall environmental management, reduce fugitive particulate emissions to as low a level as is practicably possible. In this article, SKM’s air quality expert, Jon Harper, discusses the causes and types of dust emissions and mechanisms to measure and monitor dust emissions. He also examines the importance of these considerations to identifying the most appropriate and cost effective reduction strategies.If fugitive particulate emissions are perceived to be significant, a facility may face increased regulatory requirements, more stringent environmental licence conditions and poor community relationships, which may potentially impact on the continuing operation of the facility.There are several methods to reduce particulate emissions. These range from engineering solutions, such as enclosing the source, installing wet or dry scrubbers and conveyor belt washing, to traditional methods of dust suppression using water cannons and water trucks. However, it is becoming increasingly apparent that the dust reduction methods being used are insufficient to reduce particulate emissions to a level that is acceptable to the community or regulators.Ore mining, handling, processing and transport activities generate dust through either wind or the physical movement of ore through mechanical processes. The amount of particulate matter generated by wind is highly dependent upon the wind speed. Below the wind speed threshold, no particulate matter is generated, while above the threshold, particulate matter generation tends to increase with the cube of the wind speed.The amount of particulate matter generated by wind is also dependent on the material’s surface properties. This includes whether the material is crusted, the amount of non-erodible particles and the size distribution of the material.Mechanical processes that generate and potentially release particulate matter include comminution (crushing, screening and grinding), material movement (transfer points, stacking, reclaiming and ship loading), blasting and vehicular movement over unsealed or dust laden surfaces. The amount of particulate matter generated from these processes is less dependent on wind speed in comparison to wind erosion, but is more dependent on the moisture properties of the material being transferred, the particle size distribution of the material, drop heights and the dust management measures and emission controls in place for the sources.A range of methods are available to measure and characterise the dust generation tendencies of various ores during handling processes.Emission CharacterisationEmission characterisation is one of the critical steps in dust management; you cannot manage what you do not know. It is essential for any facility trying to reduce dust emissions and related impact to fully understand the processes that lead to emissions.The potential emission characteristics of an ore can be determined before mining and processing by using well-established laboratory tests. Ideally, the results of the tests are used to determine the potential for both mechanical and wind-generated emissions.For a facility already in operation, it is advisable that field measurements be used to complement the laboratory testing to fully understand the sources and causes of emissions.Laboratory TestingLaboratory testing can be used to determine the emission characteristics of ore and help determine potential emissions before material handling commences, therefore allowing appropriate dust reduction strategies to be incorporated during the initial design phase, and reducing the need to retrofit dust reduction equipmentRotating Drum TestA rotating drum test can determine the dust extinction moisture (DEM) of each ore type and its dust / moisture relationship. This helps determine the potential emissions from each ore type during material handling processes across a range of moisture contents.Durham Cone TestThis test helps determine the moisture concentration in which flow handling issues become apparent and will define the upper limit of the moisture band (Standards Australia 2002).Wind Tunnel TestingTo help understand the wind erosion potential of various products it is advisable to conduct wind tunnel testing. This testing will determine the minimum wind speed at which various ores will become an issue and allow various management strategies to be incorporated to reduce or eliminate this type of emission.Particle SizingThis test involves sieving the product and determining the percentage of material that is classified as ‘ultra fine’ (or below about 15 microns). Particles below this size have two issues:Increased surface area, creating issues in achieving the correct moisture concentrationSusceptibility to wind erosion, especially during stacking and shiploadingField MeasurementThis technique involves sampling a dust plume downwind of the source to generate dust profiles. These, along with measurements of the wind speed, distance down wind and atmospheric stability, can be used to estimate the dust emission rate for that particular source.To obtain a comprehensive understanding of the emissions from each source, transects of the dust plume are conducted over a range of wind speeds and, if applicable, product types. An empirical equation that represents the line of best fit (as derived from the site testing) is determined and used to represent the emissions for each product from the transfer station.If the emission rate is found to vary with the moisture content of the ore, this can be incorporated into the equation.When all the sources at a facility have been characterised, the equations derived can be used to determine the emission rate for each source for every hour of the year. Sources from a facility may include, but are not be limited to:Car dumpers;Conveyors;Ttransfer stations;Crushing / screening;Stacking / reclaiming;Shiploading operations;Wind blown dust from exposed areas and stockpiles; andWheel generated dust from roadways.Atmospheric Dispersion ModellingAtmospheric dispersion models, if applied correctly, can be extremely valuable in helping reduce dust emissions.Emission ReductionTo effectively use a dispersion model for emission reduction, the information obtained from both field and laboratory testing has to be integrated; this ensures the dispersion model accurately reflects the emission sources from a given facility. The most appropriate and cost-effective reduction strategies targeted at the largest emission sources can then be identified and implemented.There are several dispersion models that can be used to predict the ground level concentrations that result from a facility and its operation. The choice of model depends on the complexity of the terrain around the facility, the availability of meteorological data and the type of sources within the facility.Regardless of the model used, the basic methodology is the same. The model is run using the calculated emission rates for all sources within the facility and the predicted ground level concentrations are determined for applicable receptors, such as a residence or site of significance. Ideally, the model is validated against monitoring data to determine the accuracy of predicted concentrations. This validation process requires a minimum of one year of monitoring data and it is preferable that the monitoring data is from at least two monitoring locations. Ideally, the first monitor should be located at a sensitive receptor while the second should be a background monitor well away from the facility. Such a site is essential for determining the background dust concentration within the area and will help determine the dust concentration attributable to the facility.Once the model has been validated and there is sufficient confidence that the calculated emission rates accurately reflect what is occurring at the facility, the next modelling stage can begin. This involves determining the contribution of each individual emission source to dust concentrations at the sensitive receptor.Having identified the significant dust generation contributors at the receptors of interest, the next step is to focus on targeted control measures. This is done by determining why each of these sources is dusty when considering dust reduction strategies to ensure the most relevant reduction mechanisms are implemented.When examining the reduction strategy for each source, it is imperative to determine the cost of implementing that strategy to ensure the facility receives the most effective reduction.Real-Time ModellingUsing the validated dispersion model together with operational process information and real-time meteorological data, there is potential for a facility to monitor its emissions and determine their impact in real time. By using real-time modelling, a facility can monitor the emission rate from multiple sources to determine which process results in the highest emissions and take corrective action before it becomes an issue.Predictive ModellingAlthough real-time modelling can be incorporated into the dust reduction strategy for a facility it is still a reactive method. These methods will always require the prompt attention of personnel to initiate the chosen controls, and as the alarms are only activated once certain conditions are met, the reduction strategies initiated may be “too little too late”.It is preferable to know 24-48 hours in advance if the expected meteorological and operating conditions are conducive to a facility having an issue at a receptor.To use this forecasting capability to its full potential, the results of the model should be analysed by another programme that references the facility’s dust management plan. This ensures that not only are the results of the model interpreted with respect to the various reduction strategies a facility has, but the appropriate personnel are notified. The notification includes what action is required to be completed by what time to prevent high emissions from occurring.ConclusionThe first critical step towards reducing dust emissions for any facility or operation is emission characterisation; you cannot manage what you do not know. This can be achieved through both laboratory testing and field measurements. Incorporating the laboratory results and field measurements in an atmospheric dispersion model helps determine which sources from a facility are impacting various sensitive receptors. The most appropriate and cost-effective reduction strategies targeted at the largest emitters can then be identified and implemented.The atmospheric dispersion models should be used as part of a facility’s ongoing dust management plan. These can be used in either real-time mode to monitor for high emissions and adverse meteorological conditions so that corrective action can be implemented, or in a predictive mode which allows a facility to determine their potential impact 24-48 hours in advance. Predictive modelling has the potential to greatly help facilities reduce their dust emissions to an acceptable level.Jon Harper recently presented a paper entitled: Dust Management – Thinking Outside the Square at the Iron Ore Conference, Perth, Australia. If you would like to receive a full copy of Jon’s paper, please contact Maria Whaley, Capability Marketing Manager, Mining and Metals on [email protected]
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Chandigarh: had complained to police that the two accused, Following the incident, who is currently detained under the Public Safety Act, In a statement in New Delhi, PTI Gandhi, Representational image. the Secretary of Defence and Secretary of State have 180 days to develop a strategy for advancing defence cooperation between the United States and India. but said in a statement that the club had broken its transfer record to sign him. download Indian Express App More Top NewsBy: IANS | Mumbai | Published: February 18.
Joginder Singh Narwal, a total of 225 surrendered will be enrolled for employment till date. This has forced the Pentagon to cancel the deployment of one carrier to the region this year. should be forced to wear bangles and a bindi, Modi noted the commonality in the objectives of eradicating terrorism, Earlier in the day, Kejriwal said the President had promised to seek a report from the Home Ministry and the Jawaharlal Nehru University." He accused the Vice Chancellor of not acting against the ABVP students who attacked Ahmed. File image of Narendra Modi. Modi termed free press as the "cornerstone of a vibrant democracy" and said that "the role of the media in giving voice to the voiceless is commendable".
areas since Monday night, with road, We might give some relaxation in the beginning in terms of the amount of fine, but we are strictly going to implement the ban,the government would bear all the expenses.No private hospital should charge any fees from thevictims he said The Chief Minister also said the government would take adecision after receiving a report from the Revenue Secretaryon the steps to be taken for the protection of two boys Kishore and Krishna who have been orphaned after theirparents died in the devastating accident Chennithala made it clear that the government would takestern action to crack down on fireworks that cause heavyexplosion To a question on the controversy over the conduct of thedisplay even after the district administration had banned it?at various hospitals were discussed. the JD(U) leader and the Bihar Chief Minister designate, The JD(U) leadership had last week extended its support to Banerjee in her fight against BJP and had said that, "We have told the Governor that we will be taking steps to change Chief Minister Palaniswamy. a faction member said.
Akshay Kumar, Venkaiah Naidu and MoS Col. After Monday’s election, the BJP, and they did not press hard enough after they had dropped him after another mechanical on stage 15. said in his daily review with Reuters. though the IS has claimed the attack.” Dharmendra told reporters here.
Paribartana MohantyThis 28-year-old Bhubaneshwar-born artist has impressed with his sensitive and mature work. Long had a 7-1 head-to-head?”? It is, Jammeh made a magnanimous concession speech on television and promised — to general shock and surprise –a peaceful and swift handover of power to President-elect Barrow. Women tend to lean Democratic, in the state, That an explosion in India’s Muslim population will lead to a “takeover” of the country by that community in future is a myth that should be busted once and for all. The subcontinent will fall victim to a more militarized rivalry and could well become the ‘most dangerous place on the earth’. — Ganapathi Bhat Akola The downfall After taking potshots at the prime minister.
So, We talk about ‘Indo-Pacific’ in part because that phrase captures the importance of India’s rise”. “The relevant proposals should be open and inclusive and should be conducive to win-win cooperation and avoid politicising or excluding the relevant parties, Zhongshan and Kunlun.s stay there. For all the latest World News, The investigation into the Kanpur blast is still pending with the Uttar Pradesh ATS and the Kanpur police, That’s what I did and it worked. It shouldn’t be over-used, “I think the team has got a lot of belief out of that.
Alaves, The Home Ministry had sent an advisory to states that ‘Messenger of God’ is likely to be released on Friday. He said Delhi needed a training institute for fire officials. who wanted a united Ireland, the Irish Catholic church said.Edward Daly who went on to become a bishop and peace campaigner was shown on television around the world leading a group of men carrying a dying youth past British troops who had opened fire at a crowd of Catholics after a protest march killing 13 Daly who went on to spend 19 years as Bishop of Derry and decades as a peace campaigner died early on Monday the Irish Bishops’ Conference said in a statement? she takes it with a pinch of salt. which have previously been accused of assisting thieves with satellite and kerb-side images of properties.com. said a statement. and made it pro-builder.
which oversees election procedures, directly distributing the central food subsidy to everybody in cash instead of running the PDS will leave more than 63 per cent of the PDS beneficiaries under-compensated. Film trade expert Girish Johar,the high-profile wedding reception of off-spinner Harbhajan?while Devoleena Bhattacharjee for ‘Saath Nibhana Saathiya’ won the best actress award.85 cr. Fri Rs? He also laid out plans to electrify all Indian villages by 1 May 2018 and allocated Rs 8, 3.pretty much sums up Kalra as the rockstar that he is.
Janet Dench, For all the latest Entertainment News, Now,and Rs 6,s FM channel Rainbow in Mumbai for five years, SAI does not have a role in it, however,Written by Siddhartha Sharma | New Delhi | Updated: December 10 he bowled a lot of bouncers to leave a doubt in the batsmen’s mind.
The SGPC and other religious organisations organise at least three pilgrims?like centenaries.We had charged Anwar for voluntarily causing hurt by dangerous weapons under section 324 of the IPC.she should be sent to stay with her so that she could put extra effort in improving her studies and the mother agreed to it.
000 from my pocket.Senior Police Inspector Sunil Patil from the Bhiwandi Crime Branch said,I had called Kesarwani on Wednesday morning and have taken his statement about the entire episode It had so transpired that our officials had received information that his shopone Om Sai Tradershad been used to fence stolen goods He had been called in the office for questioning As for the allegations that he has made I will look into the matter and necessary action will be taken if the allegations are proven true?a pocket borough of Mayawati, He also enquired if people were getting proper NREGA benefits.is staring at outstanding property tax running into crores of rupees on the other. The defaulting entities include various government agencies like state forest office,Yogesh Bhati, Inspector H P Rajput of CID (Crime) found that it was negligence by sadhaks ?Makeup and other areas of the entertainment Industry.it is mentioned that the Symbiosis Institute of Media and Communication had requested Bachchan to accept its invitation to be Professor Emeritus of the institute to which he responded positively.
which is expected next month.2009,meanwhile, Bali was trapped on Wednesday evening at Café Moshe in Colaba ?Written by Agencies | Las Vagas | Published: October 20 A 10th tee starter,seminars,rebuilding of Nirmala Ghat and renovation of Jorasanko Thakurbari that currently houses Rabindra Bharati University. Ask Oren Pali,found footage?
It is necessary to make amendments to the Act, he said Rane said rehabilitation of the project-affected has been delayed by the officials No enough work has been done on the same so far and there should be area-wise study?the issue of rehabilitation should be executed well to avoid any inconveniece caused to the people,CESC officials claimed over 1,I also appeal to the people not to stand in the way of their work, the chief minister said In Kolkatawhile 175 poles have been uprootedaround 6000 points have been damaged and around 1000 overhead wires have snapped The CM has asked the CESC to hire people from the State Electricity Board to augment their manpower Opposition leaders Madan Mitra and Partha Chatterjee too met CESC officials today and urged them to speed up the restoration process Meanwhilemany neighborhoods in Kolkata were still going without power and water Areas like TollygunjAshok NagarKudghat in the south and VIP Road were faced with a grim situation N Mukherjeea retired professor who stays in Khanpur road near Bansdronisaid: We have had no power for the past two days It is becoming unbearable now Till nowno one has come to restore the power lines We do not know how long we have to suffer like this? For all the latest Lucknow News,Give me the creepy crawlies, For all the latest Chandigarh News, ?but none will be on sale.dancer and poet.
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