Drilling and blasting is made up of groups of tasks, which are performed to produce broken rock with specific fragmentation and muck pile shape & displacement while ensuring that safety, statutory requirements and/or environmental compliance are met. Procedures need to be defined for carrying out drilling and blasting to obtain desired results. Data collection: pre-blast, during the blast and post-blast is critical to the blasting process -- for blast design, for prediction of impacts, for taking corrective steps at execution stage and for further analysis and plan-ning purposes.
Generally blasting related information is poorly managed with disjointed and unrelated information technology systems managing parts of blasting data. Data is often moved from one system to another, sometimes manually. A data management system not only ensures information storage, but also acts as an intelligent system for optimization of blasting and overall operation. The review and analysis of past data can improve blast design, blast execution and help in the achievement of desired blasting outcomes and downstream productivity, and process im-provement by adjustment of drilling and blasting pa-rameters. Based on the database and its search and
analysis capabilities, the system can provide oppor-tunities for taking corrective steps by changing ex-plosive charge distribution, initiation timing and se-quence for controlling fragmentation size, vibration and flyrock. Data obtained from blast face profiling tool, vibration, flyrock and fragmentation prediction tools, can be directly linked to a database incorporat-ing explosives and accessories used. Modular soft-ware may use information to create specific hole by hole explosives loading and create load sheets ac-cording to geotechnical zone characteristics and re-sults required.
An important component to the management of any process is the measurement of key parameters, which in turn are used to monitor, control and pro-vide the feedback necessary to improve the process. Any “optimization” (or improvement) of blasting should not only look at the blast itself, but also to all consequences of blasting results. These considera-tions lead to overall-integrated concept. It is obvious that such approach not only provides data for blast-ing improvement, but will also be helpful for im-provement of all other operations as well.
Several commercial database systems for mining and blasting are available for storing and analyzing data. However, blasting related data base systems have not found to be popular at the mine level by In-dian mining and blasting organizations. Organiza-tions are either recording data in registers and/or are using excel sheet. Difficulty is about customizing imported software and also updating the database. Further, blast execution is not similar in different countries while using similar explosives and initiat-ing systems. In general, mines are keeping blast data in paper based system and have generally not bene-fitted from recent technology advancement. Draw-backs of the system include that record retrieval is time consuming, record cannot be used for analysis, and insufficient data are recorded. Advantage of us-ing information technology data base are systematic storage of data, retrieval of data over a long time period, analysis of data for improving efficiencies, automated reports, view and analysis at distant loca-tion if desired. In general separate reports have to be prepared/ submitted to different regulatory authori-ties, to management and also needed for own re-quirement of mine operators. This paper discusses how computerized data collection and analysis can provide improved blast accuracy and performance achieved through a more intelligent blast design, made possible by combining with distinct data base. This is accomplished by focusing on key perfor-mance indicators derived from the historical perfor-mance of drill and blast events. The searchable data base of blasting information drives incremental im-provement in performance
2 DATA MANAGEMENT
A data management system not only ensures in-formation storage, but also acts as an intelligent sys-tem as an aid for blast design, prediction of impacts and analysis. Database can be integrated with mine planning, drill guidance, field survey, load design parameters and post-blast evaluation (Figure 1). Da-tabase is foundation for optimization of blasting and overall mining, tunneling or quarrying operation. Based on the database and its search and analysis capabilities, the system can provide opportunities for getting dynamic drilling and blasting parameters, vi-bration constants and predictions, flyrock predic-tions, fragmentation size predictions. This informa-tion helps in adjustment of drilling and blasting parameters based on optimized results.
Besides measured parameters related to blasting parameters, explosives accessories, geotechnical in-formation, environmental information are required for planning and design of blast block (Birch, et al., 2002; Hutchins, 2004; Bhandari and Bhandari, 2006, Bhandari, 2011). Blast data management sys-tem stores blast details, blast parameters, blast pat-tern, face profile, explosive consumption, charging details, costs, weather information, pre-blast survey, post-blast evaluation data, fragmentation informa-tion, photograph(s), videos, accidents, misfires,
flyrock, vibration record and information for vibra-tion analysis. Video and photographic records also provide opportunity to analyze displacement and fly-rock. These also indicate face movement and hole by hole behavior. Integration of the following also needs to be accomplished:
- Vibration monitoring results.
- Blast simulation and airblast and ground vibration reinforcement
- Flyrock and safe zone for personnel and equipment.
- Fragmentation size distribution
- Blast dust plume movement
Data obtained from blast hole face profiling tool, vibration prediction tool, and direct data link to a da-tabase incorporating all the major manufacturers products and an interface allows the user to add new product ranges and create custom products. Directly import drill patterns and pit shells from the mine planning packages. By linking with geological data/ chemical data the blast block can provide quality as-sessment.
Performance and cost of blasts can be monitored and Key Performance Indicators can be determined. Appropriate blast designs for particular areas of mine and different zones can be identi-fied. Optimizing the blasting process involves drill-ing accuracy and efficiency, profiling of exposed faces for mining applications, tailored loading ex-plosives according to face profile and rock condi-tions at depth, and designing proper parameters, de-lay timing and initiation sequence. Reports can be generated as per various requirements of the organi-zation or statutory authorities. Blast records must be held for statuary purposes and would be useful in case of litigations.
3 CASE STUDY -- ADITYA LIMESTONE
MINE Aditya limestone openpit mine belongs to Ultra Tech Cement Ltd group which has several lime stone openpit mines spread across India. Aditya mine is designed to produce 6.6 million tonnes li-mestone per annum for its cement plant, situated around 2 km away (Parihar et al, 2009). The ore to overburden ratio is 1:0.33. Thus, total rock handling is around 9 million tonnes per annum. Presently, there are two working pits. The mine is surrounded by small villages.
Geology: Aditya Limestone deposit belongs to Nimbahera limestone formation: limestone, shale and clay are the major rock types. Limestone is fine grained, thinly laminated to massive in structure. Aditya limestone mine deposit is highly jointed. The joints are multi-directional. Some of them are filled with overburden soil and clay. The deposit was sub-jected to structural disturbances of moderate intensi-ty as evidenced from numerous minor and major folds and joints.
Broadly, the structure of the entire deposit can be classified as a synform. In spite of the above folds, study of dip and strike readings indicates N - S trend with maximum of 10o deviation on either side. The amount of dip varies between a narrow range of 0o to 20o. Dip direction changes from East to West due to folding. There is plunge of about 5o in strike di-rection.
Mining: Mining is carried out by fully mecha-nized open pit mining method. The working pit is below the general topography of the area. Working pits have been developed with working benches of 9.0 m. height. At present, the work is going on in three benches. Drilling is done with the help of ROC L6 and IBH-10 drill machines of 100mm-115mm diameter. A set of about 25 holes is blasted. Excava-tion and loading operations are carried out by hy-
draulic excavators. At a time two excavators are used for this operation. Transportation of limestone from working face to crusher hopper is carried out in 35/60 tonner dumpers. Before crushing, the limes-tone from crusher hopper is passed through grizzly screen or screening out intrusive clay.
The mines have kept blasting records since the beginning of mining operations in 1995, initially in hand written format and thereafter have been main-taining records in Excel sheet format ( Figure 3 & 4) for its blasting operations, explosive consump-tions, drilling performance, blasting costs. These da-ta show considerable improvement in blasting per-formance and at the same costs have also reduced. This has been possible in spite of much increase in costs of explosive, accessories and labour and other input. Continuously several new techniques have al-so been adopted with indigenous and local methods.. Data collection and adoption of many scientific techniques such as Indian indigenous air gap, indi-genous stem plug, indigenous rock plug techniques
and tools have helped in achieving the above stated results. An example of charging with indigenously developed wooden spacers for giving ai rgap (Figure 5).
Blast records from 1995 till date ha s helped the mine in improving rock breakage of limestone powder factor from 6.5 tons/kg to 14 tons/kg (Figure 6) drill factor from 45 tons/m to 75 ton s/m (Figure 7), thus reducing costs by 50% (Figure 8) while im-proving crusher productivity from 764 t ons per hour to 932 tons per hour and controlling vibration, fly-rock and dust.
4 BLAST INFORMATION MANAGEMENT
Blast Information Manage ment System (BIMS) provides information to meet th e strategic and opera-tional needs for planning, controlling and decision-making for optimizing mining operations (Bhandari and Bhandari, 2006). BIMS provides methods to store, manage, document and retrieve drill and blast related information The syste m stores blast details, actual blast parameters, blast pattern, face profile, explosive consumption, charginng details (Figure 9),
The mine is now using blast related information data management system for record, analysis and re-porting. This indigenously developed system is reli-able, easy to use, stores large data and provides re-trieval and analysis of the stored data and also provides costs, weather information, p re-blast sur-vey, post-blast evaluation data, fragmentation infor-mation, photograph(s), videos, accidents, misfires, flyrock, vibration record and informatio n for vibra-tion analysis records (Figure 9). Softwa re also pro-vides opportunity to analyze displacement and fly-rock, back break/over break records to be maintained and analyzed.
Recorded videos and stored in the database can also be used for observing face m ovement and hole by hole behavior.
The stored blast information data can be retrieved quickly and easily. Performance and cost of blasts can be monitored and appropriate blast designs for particular areas or different zones can be identi-fied. The data management an d retrieval is easy and simple to use which can be ca rried out in a few mi-helps in optimizing various operations. Readily available past data in a logical format and blasting data analysis tools are the key features of the data-base.
Details of explosive charge distribution and initiation used for the holes
The database can be extended to integrate with other systems such as ERP, CMMS etc. If the soft-ware is operated in conjunction with a comprehen-sive monitoring program, it can contribute to the ef-ficient running of an operation and reduce environmental effects to a minimum. Importing data using .csv file, Excel and other popular mining soft-ware makes it is possible to reduce input work. En-tered data can be edited through Edit Parameters.
Figure 10. Result of blasting along with Photo-graph & Video This tool provides a way of trapping the expe-rience of drilling and blasting personnel to better control critical parameters such as dilution, vibra-tion, fragmentation, and flyrock and fines genera-tion. Integration with other software such as that used for vibration monitoring and analysis, fragmentation analysis etc. can be carried out so as to provide sim-plified management system.
Many central and state agencies, concerned with Explosives Security, Mines Safety and the Environ-mental Protection (DEP), are increasing their expec-tations for strict accounting of inventory and blast documentation. Blasting company executives and managers are now facing the possibility of incarcera-tion, fines and suspended operations if their docu-mentation is not in order. The database can be tai-lored according products and practices, to customer requirements and can be maintained.
This database has also searching options using which the user can look for the records of blasts as per his defined criteria. Currently, the software uses the following criteria for the search option: between dates, by performance of explosives or initiating sys-tem, by vibration limits, by fragmentation size, by location of blasting zone or accident etc.
Presentation of analysis of data, compliance re-ports suitable for regulatory bodies, archiving and viewing of data at distance location, costs can be de-veloped. Reports suitable for Occupational Health and Safety (i.e. incident reports) can be compiled. Key performance indicators are derived.
Figure 12. Reinforcement of vibration before blasts helps in changing delays
Database connects all information related to blasting operation to provide reporting, trends and analysis. Custom graphs and reports reduce work for providing reports to any desktop and can be fully customizable to meet key production indicators, and daily reports. Software based data base provides valuable time for engineering and mining profes-sionals by integrating disparate mining data capture software systems and removing dependencies on Excel spreadsheets. This information stored and ana-lysed helps in better control and optimization of mining operations. Data base helps to quickly re-spond to information and remain successful in to-day’s competitive market place. Web based versions and tablet PC would make data acquisition easy.
Use of database helps in improving blast efficiencies and demonstrate that an improvement has been achieved there needs to be a comprehensive mea-surement system, which is capable of setting base-line, and then tracking the changes made to the process.
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