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Home > Analyzing Effects of Air Decks on Fragmentation and Economics of Bench Blasting

Analyzing Effects of Air Decks on Fragmentation and Economics of Bench Blasting

Thesis Info

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Author

Saqib, Shahab

Program

PhD

Institute

University of Engineering and Technology

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2016

Thesis Completion Status

Completed

Subject

Mining Engineering

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13644/1/Shahab_Saqib_Mining_Engineering_HSR_2017_UET_Lahore_24.12.2017.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725501223

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The airdeck blasting technique has been used in the past to reduce the explosive charge and to improve the rock fragmentation. However, the mining and construction industry of Pakistan has always been reluctant to use airdecks in their blasting operations. This is due to the fact that researchers and practitioners have a divided opinion about the efficiency of this technique. In fact, several attempts in the past have been made to find out the best position and optimum length of airdeck for better fragmentation. Since, in the previous studies most of experiments were carried out under varying geological conditions, it was very difficult to suggest the best possible location and optimum length for airdeck in an explosive column for better fragmentation. In order to find out the best position of airdeck in explosive column that yields better fragmentation, it was necessary to carry out all experiments on homogeneous material and in controlled geological conditions. So that research findings indicate a correlation between the concerned variables only and a benchmark research could be established. Therefore, special homogeneous concrete blocks were designed for this research. These concrete blocks eliminated the heterogeneity and anisotropy of rock material, such as the fractures, folds, faults and joints of rock. Such factors have been found to play a very crucial role in the size of debris produced from the blasted rock material. This research will address two fundamental questions; the technical and the economic efficiency of the airdeck blasting technique. All the blasting experiments in this study were carried out in two phases. In the first phase, a series of small scale experiments was conducted using homogeneous concrete blocks. In order to find out the proper position and optimized length of the airdeck, it was ensured that the concrete blocks had almost the same uniaxial compressive strength. More than 40 tests with concrete blocks were performed for this purpose. The evaluation of fragmentation by sieve analysis revealed that an improved rock fragmentation was achieved when the airdeck was placed in the center of the explosive column. Moreover, it was also observed that the mean blasted rock fragment size increased with the increase in airdeck size and the best results were achieved at 20% airdeck length. In the second phase of this research, the results of experimentation on concrete blocks were validated on relatively homogeneous limestone at two cement quarries: DG. Cement Chakwal and Askari Cement Nizampur. Several test blasts were carried out with full column charge without airdeck and with 20% airdeck length placed at middle of explosive column. The analysis of fragmentation for the benches after blast was done using Split Desktop software. Subsequently it was deciphered that at both the cement quarries, better fragmentation was achieved by placing airdeck at middle of explosive column as compared to when there was no airdeck in the full column charge. This research work also includes the use of multiple airdeck lengths placed at middle position of explosive column for the limestone quarry and the results indicate improved fragmentation. The results of this research work clearly indicate that airdeck, when placed at middle position of an explosive column produce more uniform blasted rock size distribution compared to that at other positions. Moreover, the optimum length of airdeck is 20% of the total length of explosive column and it improves environmental factors like fly rocks, air blast, ground vibrations etc. The underlying reason behind this is that the airdeck at middle position results in multiple impacts of shock wave that leads to an efficient transfer of explosive energy in the surrounding rocks. Economic analysis of explosive cost at both quarries was also conducted in this study. From economic analysis at DG Cement Chakwal, it was observed that up to 2.5 rupees per tonne of explosive cost could be saved by adopting 20% mid-airdeck length in the explosive column as compared to the cost incurred for conventional blasting techniques. By using above mentioned technique, saving per tonne can be increased by 16% and rupees 750,000 can be saved at the DG. Cement quarry monthly assuring an annual saving of rupees 9 million. Similarly, the economic analysis conducted from the results of blasting at Askari Cement Nizampur, it was observed that 2.6 rupees per tonne of explosive cost can be saved by adopting 20% mid-airdeck length in the explosive column to enhance the fragments as compared to the cost incurred for conventional blasting techniques. Therefore, using 20% mid-airdeck length in explosive column, saving per tonne can be increased by 10.4% and rupees 468,000 can be saved at the Askari Cement quarry monthly assuring an annual saving of 5.6 million rupees. By using 20% airdeck lengths in explosive column, Rs. 44.33 million can be saved annually for explosive used by Punjab, province of Pakistan. This amount can be calculated for other provinces of the Pakistan as well. There are many other minerals is Pakistan which require blasting for their production. If we could use the improved airdeck blasting technique for the production of those minerals, billions of rupees can be saved annually. Moreover, by incorporating the effect of even fragmentation from blasting on downstream processes like crushing, milling etc. millions of rupees can be saved. It is anticipated that this study will provide answers and guide lines to researchers and practitioners who were confused about best location and optimum length of airdeck to be used in explosive column for achieving the optimum fragmentation.
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بجلی کے بحران پہ کیسے قابو پایا جا سکتا ہے

بجلی کے بحران پر قابو کیسے پایا جاسکتا ہے
نہ چھوڑیں واپڈا والے اگر بجلی تو کیا غم ہے
’’یدِ بیضا لیے بیٹھے ہیں اپنی آستینوں میں‘‘
انسان گھر میں موجود ہے۔ گھر کا سارا نظام اس کی سر پرستی میں بحسن وخوبی رواں دواں ہے۔ دریں اثناء گھر کے آنگن میں خفتہ شیر خوار بچہ آواز کے ساتھ رورہا ہے اور اس کے رونے کی وجہ کوئی بیماری نہیں، کوئی اور خار جی عمل نہیں صرف اور صرف لوڈ شیڈنگ کے سبب شدت حرارت ہے جس نے معصوم کی نیند حرام کر دی ہے، اس کی اس بے چینی نے والدین کے قویٰ کومضمحل کر دیا ہے اور پورے گھر میں ایک بحران کی سی کیفیت ہوگئی ہے۔ اور اس قسم کے بحران صرف کسی خاص علاقے میں نہیں ہیں بلکہ ملک کی کثیر آبادی اس سے متاثر ہے۔
برقی رو کی کمی یا قلت سے ہر ایک متاثر ہوتا ہے۔ لائبریری میں کوئی پرسکون فضاء میں محو مطالعہ کتب ہو، یا ظرف ہائے طعام اُٹھائے موجود غلام گردش ہو، کوئی کوچہ بازار میں موجود ہو، یا کوئی گھر کی بالکونی میں قیام پذیر ہو، کوئی صنعتکاری کے میدان سے مربوط ہو، یا کوئی زراعت و کاشتکاری کے میدان سے وابستہ سب کے سب بجلی سے نبردآزما ہیں۔
اس بحران پر قابو پانے کے لیے اقلیم عقل و خرد کی فرمانروائی کے ساتھ نصرت الٰہی کا طلبگار ہونا ہو گا۔ اس مہیب سائے کواجالے میں بدلنے کے لیے ابتدائی طور پر کاشانۂ خویش کو سامنے رکھنا ہو گا۔ اصراف وتبذیر جیسی خصائل قبیحہ سے کنار کشی اختیار کرنی ہوگی ،کفایت شعاری جیسی خصلت صالحہ کو اوڑھنا بچھونا ہوگا۔ اگر ایک شخص فضول خرچی جیسی لعنت سے چھٹکارا حاصل نہ کرے اور دن رات اسی عادت سے وابستہ رہے تووہ بھی اپنے مقصد میں کامیاب نہیں ہو...

دور المعاهد والأقسام للترجمة في العصور العربية الزاهرة وحاجة انشائھا في أقسام اللغات بالجامعات الباكستانية

Translations have a prominent role in the advancement of science and literature for any people. By which sciences and arts move from the literature of one nation to the literature of another nation, in which sciences and arts flourish, and a nation becomes acquainted with the literature of another nations. Translation is an independent art, as it depends on creativity, linguistic sense and the ability to bring cultures closer, and it enables all mankind to communicate and benefit from each other's experiences. It is an art as old as written literature. Translation is a cultural necessity and an intellectual activity, and it extends bridges of communication between civilizations that converge and diverge among themselves, and their languages are similar and differ in ways of expression and methods of statement and expression of ideas, feelings and attitudes, and in the worldview and understanding of its concepts. There is no doubt that translation it is a complex linguistic process that requires lengthy anchors, as the queen of the two tongues is acquired only by a lot of practice, in addition to the systematic study of the mechanisms of transmission from one tongue to another. We also see in the modern era that the Arab Scientific Academy in Damascus, the Arabic Language Academy in Cairo and the Iraqi Scientific Academy have a clear and prominent role in the advancement of Arabic sciences and literature. The Scientific Academy in Damascus has established the Arabic language and its terminology, and the language of bureaucracies, in particular, with the help of authors and translators in particular, and the Academy of the Arabic Language in Cairo, which has made efforts in developing the great linguistic lexicon and terminology of modern sciences.

Environmental Impacts of Phosphate Fertilizer Industries in Pakistan

Modern agricultural practices are depleting natural mineral content of soil required for efficient growth of plants. In order to overcome the reduction of minerals in soil, different approaches are used; e.g. use of manure, organic and inorganic fertilizers etc. Application of phosphate fertilizers is one of the options. Unfortunately addition of desired minerals through fertilizers also accompanies the undesired heavy metal content (stable and/or radioactive). Continuous application of fertilizers may result in buildup of heavy metals, thus, posing a threat to the environment and plants, and consequently to human life. The present study was conducted to investigate the extent of the threat caused not only by phosphate fertilizers (PFs) but also by phosphate rock (PR) and precipitated calcium carbonate (PCC). Representative samples of PR from Hazara deposits, Pakistan, various types of PF used in Pakistan and the fertilizer waste, PCC, from a local fertilizer industry, were taken and analyzed for their radioactive and heavy metal content. Radioactivity was measured by gamma spectrometry using high purity germanium (HPGe) detector while heavy metals were determined by instrumental neutron activation analysis (INAA) technique. Some of the elements were also determined by atomic absorption spectrometry (AAS). Major chemical composition for rock samples was quantified by X-ray fluorescence (XRF) spectrometry technique. Variable amounts of elements like Ba, Sn, Th, V and rare earth elements (REEs) were present in all the studied sites of phosphate rocks. The elements Al, Cr, Cs, Fe, Sb and Zn were present in relatively higher amounts in Kakul phosphate rock crushing plant (KPRCP). Analysis of toxic elements depicts that Pb is present at relatively higher level in local phosphate rock samples while Cd and Zn are present in comparable amount. Assessment of hazards posed by heavy metals in PR showed that consumers are exposed to heavy metals from various pathways. The results indicated that Pakistani PR is agronomically effective. However, it contains higher values for toxic element like Ni, Pb and Cu that may be transferred to fertilizers and then to soil and plants grown on them thus threatening human life. The specific activity analysis showed that outdoor and indoor external dose from PR is higher than the maximum value of world‟s soil background level. It was noted that all of the studied phosphate fertilizers are rich in their mineralogical (Fe, K, Mn and Na) content while NPK fertilizers contain relatively higher amount of K. The activity concentrations of 232 40 K and Th in the single superphosphate (SSP) fertilizer are lower than that of phosphorite of Pakistan. Monitoring of radon indicated greater risk for miners than the personnel working in fertilizer warehouses. Variations in heavy metal content for PCC may be due to the fact that the collected waste samples were produced from various batches of fertilizer production. The average value for outdoor and indoor external dose from PCC waste is about three times and twice the background median value of absorbed dose of gamma rays from worldwide soil respectively. This indicates the level of radiological hazard from PCC waste to surrounding environment. Corresponding effective dose was 1.2±0.1 mSv y-1, which is higher than the annual limit of 1 mSv recommended by ICRP. The analysis of soil and crop samples (edible parts of rice, wheat and mungbean) was also performed and transfer factor (TF) from soil to crop was calculated. Greater TFs for Al, Eu, Fe, K, Sc, Sr and Zn were observed for mungbean than the other studied crops. Furthermore PLI (pollution load index) values are greater than one for all the fertilizer applied soil samples except rice growing soil samples which is just below one, showing pollution load in the respective soil environment after the applications of PFs. Moreover, the calculated health risk index (HRI) depicted a greater risk to human health from Al, Pb and Sb as they have HRI greater than one. It is concluded that special attention by environmental authorities should be given to phosphate industry of Pakistan to minimize these hazards and safety measures should be taken to decrease the risk being posed from it.