An integrated technology solution for optimised and environmentally controlled blasts

Posted Date:2016-08-23 12:05:56 Posted By: Sushil Bhandari


ABSTRACT 

Blasting can impact the efficiency of entire downstream mining operation. Individual technology solutions for blasting have been available in the industry for many years but all of them only cater for certain aspects of blasting. Many of them are based on individual research and/or experiences. Some of the available software solutions are not suitable to be used in the field as that they need advanced skills or tools. Also, most do not take technology advancements like mobility, advanced data analytics, web solutions and integration into consideration. Hence, currently no technology platform is currently present in the industry that addresses all potential needs a blaster may need at the same time in an integrated manner. 

This paper presents an integrated solution that takes care of all aspects of blasting – design blasts according to mine plan; collect data after drilling has been carried out (as there is often difference in designed and actual drilled hole locations in the field); predict blast results in terms of fragmentation, flyrock, ground and air vibrations, wave front reinforcement and flyrock distance; and, after assessment, allows changes in charging, delay timing and sequence. The technology solution is a secure, cloud-hosted, web-based software-as-a-service solution that can be accessed from anywhere. 

Also it has a mobile app, which is available for both Android and iPhone/iPad. The mobile app is also integrated with the web-based solution using application programming interface calls to the central data repository. 

Case studies for two limestone mines are presented where this solution is being used in its initial format. This software platform enabled analysis of the outcome from a previous blast pattern and then subsequently allowed optimisation of blasting operations based on historical data. Uses of this platform have resulted in improved key performance indicators in these two limestone mines. The mobile app as part of this platform enables extensive field blast data capture and analysis and also various predictions before a blast. Data collected include blast parameters, individual hole charging, initiation pattern, videos, photographs and vibration records for analysis/reporting. The key features of the solution are a blast designer, a detailed blast data collection/analysis and a series of environmental predictors. These predictors give blast results in terms of fragmentation, flyrock, ground and air vibrations and wave front reinforcement and take remedial steps before blasting to optimise and control adverse environmental impact. Many features, such as fragmentation predictor and mobility solution, are completely unique features that are not available elsewhere in such a field personnel-friendly manner.

INTRODUCTION 

Drill and blast is an important part of the mine value chain. Business improvement through drill and blast activities has become a major focus area for companies looking to drive down costs, boost productivity and meet operational demands. Blasting output impacts all subsequent downstream activities. Efficient blasting benefits include better mill throughput, better loading characteristics, a reduction in need for secondary breakage and more even loading on the trucks.

Another concern for any operation is adverse environmental effects of blasting ranging from ground vibration, air blast overpressure, dust, fumes, fines and the potential for flyrock that make mining operations harmful to people and the environment and also gives the industry a poor image in society. 

Often, we see no measurement and control at different stages in the entire blasting process in the field. Most of the

time, blasts are designed manually or using different software with a target fragmentation and other results. Too often, blasts are designed and then instructions are given to field crews for implementation. There is often a difference in designed and actual drilled hole locations in the field, charging and tie-up. Though all precautions are taken, a compliance audit of execution is often absent as only some steps are checked. 

Several blasting-related software packages are available to the mining industry and these packages cater for individual blasting operations (eg for data collection, blast design software, etc) but no software is available that ties everything together (available at one place for field personnel). The blast personnel in the field are unable to utilise the years of scientific research readily available, specific intelligence based on historical site blast data, technological advances, etc. 

Ideally, they would have detailed data and an appropriate tool available to them that would enable them to make intelligent decisions on various aspects of blasting to enable them to do a blast in a controlled manner. The results would: 

••   produce appropriate sized output

 

••   ensure environmental impacts are minimised

 

••   ensure risks from blasting are minimised. 

An integrated solution has been investigated and developed to help in blasting operations (design, operational data collection, prediction and subsequent analysis). This software has several modules – Blast Designer, Blast Information Data Management, ground and air vibration predictor, wave front reinforcement analyser, fragmentation size predictor, data analysis and advanced reporting. This software has integration tools that allow the importing and exporting of data/design from other with key software packages (mining operational tools, etc), global positioning system (GPS), vibration equipment and ability to upload photos and videos. Some mines are using multiple modules of this software. In this paper, case studies of two limestone open pit mines that are using multiple modules are presented. Use of various modules of this software has seen improvements and cost reduction. Some features of this software (fragmentation predictor or end-to-end mobility solution) are completely unique and not available elsewhere. In the following section, the research and the key outcomes are described when developing this solution.

with precision, accuracy and ease of use. This makes it suitable for use in the field by blasting personnel. This tool predicts the impacts of blasting (air and ground vibrations, flyrock, etc). This solution allows organisations to scrutinise their multiple aspects of blasting operations and improve on them before and after the blasts. Figure 1 shows that all information that goes into database applications may be used in various aspects of blasting. 

This software platform is available both in Windows and web hosted cloud based solution. Solution is built on

ASP.Net, VB.Net (Windows application), C# and SQL Server 2008 R2. This enables hosting the solution on premise or in a hosted solution in the cloud, so that user can sync data in those whenever he connects to his desktop or internet. To develop the mobility solution quickly we used MobileSmith™. This is an enterprise-class, flexible mobile app development platform that has helped us in creating the mobile application very quickly. Table 1 gives details of different modules as a part of this integrated solution. 

The features of these modules are described in the following sections.

Surface Blast Design module 

This module provides design of blasting pattern according to rock conditions, rock structure and results required for optimised results, considering explosive properties, drilling, environmental restrictions and equipment and subsequent operations. The solution helps to calculate and draw blast parameters (ie burden, spacing, square/staggered pattern layouts and delays). It includes the ability to generate a firing pattern for a blast. It allows change of delay timing and

IMPROVED BLASTING TECHNOLOGY 

Mining companies simply cannot ignore the benefits of utilising better data and technology tools when doing blasting operations. It is envisaged that drilling and blasting technologies will gradually become part of an integrated mine control system. Information technology can be used in every step of drilling and blasting operations. The integrated platform described in this paper takes data at the blast site as input and can do various predictions like fragmentation size distribution, ground and air vibration, wave reinforcement analysis, flyrock distance calculations and thereafter checking for design restrictions so that charging and initiation sequence can be altered if necessary. Users can take this application in their mobile/tablet/iPad at the mine site and collect data and get various predictions without internet connectivity. Also, as a large amount of data cannot be stored on a mobile/tablet’s local memory, it has an export option through which all collected data and predictions can be saved in any permanent storage. 

This platform ties multiple aspects of the blasting operation together (prediction prior to the blasts, data collection in mining operations, analysis/reporting on various aspects of blasting operations). Today, there are mobile solutions one can rely on to withstand rough conditions and still perform

 

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sequence, and the pattern drawn can also be saved and the blaster can be provided with a charging sheet. It also provides the first movement of rock. The software shows the simulation (animation) of ignition sequence and users can subsequently make changes in both the order and firing pattern before the pattern is released. The program provides output, charts and graphs, as well as reports in real time and allows output of data via customisable printing capabilities. Drill hole data, 

GPS data, total station records and face profiler records can be easily imported/exported. 

Blast Data Management module 

The Blast Data Management module provides methods to store, manage, document and retrieve drill and blast-related information The system stores blast details, actual blast parameters, blast patterns, face profiles, explosive consumption, charging details and all measurements like vibration records, photo and video (Bhandari, 2011; Bhandari and Bhandari, 2006). 

The stored blast information data can be retrieved quickly and easily. The performance and cost of blasts can be monitored and good or poor blast parameters for particular areas or different zones can be identified. The data management and retrieval is easy and simple to use, which helps in optimising various operations. Readily available past data in a logical format and blasting data analysis tools are the key features of the database. The database can be extended to integrate with other systems such as ERP, CMMS, etc. If the software is operated in conjunction with a comprehensive monitoring program, it can contribute to the efficient running of an operation and reduce environmental effects to a minimum. Importing data from .csv file, Excel and other mining/blasting software makes it is possible to reduce input work. Entered data can be edited through edit parameters functionality. The database can be tailored according to products and practices, to customer requirements and can be maintained. This database also has searching options, which the blasting engineer/supervisor can use to look for the records of blasts as per his defined criteria. 

The software can use several criteria for the search option: between dates, by performance of explosives or initiating system, by vibration limits, by fragmentation size, by location of blasting zone or accident, etc. 

Protection and regulatory authorities are increasing their expectations for strict accounting of inventory and blast documentation. Blasting company executives and managers are now facing the possibility of incarceration, fines and suspended operations if their documentation is not in order. Using this module, the presentation of analysis of data, compliance reports suitable for regulatory bodies, archiving and viewing of data at distance location, costs can be developed. Reports suitable for occupational health and safety (ie incident reports) can be compiled. Key performance indicators are derived. The system also provides defensible data that can be provided to regulatory authorities to illustrate the mine operator’s compliance with regulations.

the entire fragmentation size distribution, taking into account intact and joints rock properties, the type and properties of explosives and the drilling pattern. This type of prediction allows blasts to be designed according to fragmentation size requirements (Cunningham, 1983; Engin, 2009). 

Prediction and control of environmental impacts 

Increasing numbers of mining operations are coming under pressure to monitor and reduce blasting-related safety and environmental hazards (Bhandari, 1997). Ground vibrations, air over-pressure, flyrock, dust, blasting fumes and leaching of chemicals in the blastholes and polluting groundwater are some of the undesired events associated with blasting that collectively affect the surrounding environment adversely. 

Much work has been carried out on the environmental aspects so that ground vibration and airblast control operators are now aware of the steps that need to be taken. Norms and standards regarding ground vibration and air blast as specified by regulating agencies must be complied with. It is therefore vital for the industry to do all that it can to reduce the vibration levels experienced at these adjacent properties without imperilling the financial viability of the enterprise. 

There is often a difference in designed and actual drill hole locations. Drilled hole data can be used for predicting the environmental impact of blasting, and if the environmental limits for vibration and flyrock imposed by regulatory authorities or by management exceed these explosive charge distribution and initiation timing and sequence can be changed so that limits are not exceeded. For this purpose, software modules like the wave-reinforcement predictor and ground and air vibration predictors have been developed by

Richards and Moore (1995) and integrated with the blast data management system and other predictors.

Blast vibration prediction and compliance 

A comprehensive blasting vibration analysis, prediction and reporting software meets the needs of both operators and regulators. It supports and improves compliance with blasting-related planning conditions and contributes to improved blast performance and blast design. Key features are discussed later in this paper. 

Regular updating of predictions using ongoing site data, providing minimum instantaneous charges to the operator that ensure compliance with vibration level restrictions by design rather than by accident. The system’s advanced analysis also allows blasting on individual benches or areas to be assessed and the financial and environmental risks and benefits of changes to be evaluated rapidly and reliably, optimising costs and maximising efficiency. 

Fragmentation size predictor 

Over the past few decades, significant progress has been made in the development of blast design and blast fragmentation size prediction. Rock fragmentation depends on many variables, such as rock mass properties, site geology, in situ fracturing and blasting parameters, and, as such, has no complete theoretical solution for its prediction. However, empirical models for the estimation of size distribution of rock fragments have been developed such as those based on the 

Kuz–Ram fragmentation model. This method is able to predict

Flyrock prediction 

Damage due to flyrock from blasting is one of the main causes of strained relations between quarry management and neighbours. Flyrock distances can range from zero for a well-controlled mine blast to nearly 1.5 km for a poorly confined large, hard rock mine blast. There is need for quick estimation of probable distance to which a uncontrolled rock (flyrock) can be thrown. With this estimate, safety factors can be used for the removal of equipment and personnel at the time of blasting. 

Richards and Moore (2004) gave an empirical relationship and have been using software for estimating flyrock distance. Inputs to the software are charge mass, burden or stemming height, and a site constant that lies within a general range that can be tightened by site calibration. The output is the distance that rock will be thrown, and this quantification can be used to establish both safe clearance distances and the critical range of burdens and stemming heights where the situation changes rapidly from safe to hazardous. The zone of flyrock travel is indicated by this tool using safety factors and danger zones for machinery and persons respectively. If it is not possible to remove any structure or person, then one can change the charging of holes. 

MOBILITY SOLUTION 

In recent years, there has been growing convergence of ‘consumer’ technologies that we use every day on our iOS and Android devices such as cameras, motion sensors and

 GPS systems (Akella et al, 2008; McHattie, 2013). The use of mobile devices makes it easier to collect data on-site and it is mainstream in many places where a mobile workforce is present. Use of these devices would be ideal in the field for drill and blast personnel. Though mobile devices are not be used within 30 m of a blast, appropriate rugged devices can be used. They would get the required capability of collecting on-site blasting details. As part of the technology solution a mobile app has been developed with the following features. 

Figure 2 shows the basic concept of the mobility solution. To use this application, mining personnel can take the device to a blasting site. Then drilling and blasting data is entered 

(as per design) preblast (Figure 3a). Once the blasting is done, actual data is recorded to save it for future use. All parameters related to drilled holes and explosive charging, stemming, etc can be collected. At this stage, the blaster can recheck predicted fragment size distribution, flyrock distance, ground and air vibration, fragment size, etc, and if there is variation from the designed blast and limits are exceeded, changes in charging, stemming, initiation devices and timing can be done before executing the blast. Photographs and videos can also be saved using the device. Data can be imported from other devices or tools such as vibration monitoring record. 

When mining personnel return from site, they can sync this data to the web version of the application and export it to the 

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Wave reinforcement predictor 

Wave front reinforcement has been found to cause substantial increases in both air and ground vibration from both surface and underground blasting operations. Simple alterations to firing patterns can prevent wave front reinforcement and be used to control vibration levels in many situations. Pattern Analyser is a graphical software program for the design and editing of blast designs (Richards and Moore, 1995). It gives engineers and blasting personnel the ability to design and optimise the layout and initiation sequence of blasts. Analysis of data imported from other software can be carried out. By changing delay timing or sequence, reinforcement can be avoided, thus lowering maximum vibration levels. This tool allows blasting to be designed to reduce exceedance of vibrations both for airblast and for ground vibrations.

 

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desktop because local storage of mobile devices cannot save large amounts of data. Figure 3b gives an example of flyrock prediction. Figure 4 gives details of fragmentation prediction steps. Similarly, this tool can be used for ground vibration and airblast prediction. Simulation and wave front reinforcement analysis can also be carried out.

 

CASE STUDIES 

Two limestone open pit mines are using initial formats of these modules. These mines use the solution before a blast is carried out, actual drilled hole locations are measured and predictors are used to check fragmentation results, vibration and flyrock distance and, if necessary, explosive charge loading, delay and initiation sequence are altered for controlling environmental impacts. The use of this has improved safety and environmental impact and has reduced drilling and blasting costs. In one year, there has been improvements and cost reduction.

 

Aditya limestone mine 

The Aditya limestone open pit mine is designed to produce limestone 6.6 Mt/a. The ore to overburden ratio is 1:0.33. Thus, total rock handling is around 9 Mt/a. Presently, there

 

 

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are two working pits. Working pits have been developed with working benches of 9.0 m. Drilling is done with the help of ROC L6 and IBH- 10 drill machines of 100–115 mm in diameter. A maximum set of 25 holes is blasted as and when required.

 

This mine has been able to store blast-related data from the beginning of the limestone open pit mine in 1965 until the present day. This has helped the mine in improving the drill factor from 45 t/m to 75 t/m and the breakage of limestone from 6.5 t/kg to 14 t/kg of explosive, thus reducing costs by 50 per cent while improving crusher productivity from 764 t/h to 932 t/h and controlling vibration, flyrock and dust.

 

This mine initially used to keep blasting-related data in handwritten format and thereafter they used to maintain records in Excel. In 2011, Aditya mines obtained and started using Blast Information Management System software in a client server version (Parihar and Bhandari, 2011). This software stores data related to blasts taken in the mine. For the evaluation of post-blast results, the software is very useful, providing the facility of data retrieval in a number of ways. By keeping records, mines have been able to reduce costs and improve blasting operations. Using analytical facilities in the tool, it was realised through fragmentation size records that while overall blasting costs reduced, transportation and crushing costs increased. After maintaining the powder factor at around 15 t/kg for almost a decade, the mine increased explosive consumption by changing the powder factor to 13.81 t/kg and saw an improvement in crusher performance and excavator performance (Figure 5).

 

 

 

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After entering the required data, the software provides a facility to produce blast reports along with photographs and blast videos. The data management system provides for the better and systematic management of the blasting operations for the mine of longer periods. 

From the data analysis, it was realised that even after reducing the size of blasts to maintain the vibration level below 5 mm/s (as per regulatory standards), the mine was getting complaints from nearby villages. Data was examined (Table 2) and showed that, in several cases, airblast levels were exceeding 115 dB. These blasts meant that people were experiencing inconvenience in the nearby villages and were complaining. The mine obtained software for wave front reinforcement analysis of a drilled pattern before carrying out a blast to check for reinforcement of ground and airblast vibration levels and to look for the number of holes going together in a given time window.

Injepalli mine, Vasavadatta Cement

 

Injepalli mines of Vasavadatta produces 9.00 Mt/a limestone. The mine uses a Sandvik DI-500 drill machine with 155 mm hole diameter and the bench height varies from 5.0 m to 12.0 m. Bulk mixed ANFO and Raydet shock tube initiation are used. The mine started using some modules of integrated blasting solutions software for collecting blasting data and predictors in May 2014. 

Previously, the mine was using the drill pattern with a burden of 5.5 m, spacing of 10.0 m and hole depth of 10.0 m (with these parameters as, powder factor 11.60 t/kg, drilling factor 108.79 t/m, cost Rs 3.0 per ton, tonnage per hole as 1375 t). Between 2013 and 2014, the mine was using the pattern with burden of 5.5 m, spacing of 10.0 m and depth of 

10.0 m.This mine procured Blast Information Management System software, pattern analysis software and Flyrock Predictor software at the beginning of 2014. Analysis of data records of the previous blasts helped and a pattern was gradually

 

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changed to a burden of 5.25 m, spacing to 11.0 m and hole depth of 10.0 m. Changes in blast parameters show results in that cost reduced to Rs 2.8/t with powder factor improved to 12.29 t/kg, drilling factor of 111.18 t/m and tonnage per hole increased to 1443 t (per hole getting 68 t more). Thus, results showed improvement as compared with the previous blast design. Table 3 and Figure 6 show comparative results of blasting before and after using blast data software and other software. Figure 6 shows

 

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FUTURE DIRECTIONS

 

We have the scope for significant enhancements to this software suite including GPS tracking (post and preblast), incorporating geographical/soil information, embedded sensors for vibration measurement that would pass data directly to the software, advancement in the mobility solution making field data capture easier. We also want to capture data directly from drones that would enable capture of blast information before and after. This type of data can significantly enhance operational performance.

 

Many of these enhancements are still a work in progress, with some at a technical evaluation stage and some at the conversation stage. This has been envisaged as a single suite for all blasting needs in an organisation available in a user-friendly manner. It will incorporate all technological advances.

 

CONCLUSIONS 

With the availability of several tools for controlling blasting at every stage of blast design and execution, it is now possible to control adverse environmental impacts and 

improve operational management. An integrated blasting software solution has been developed and used in a couple of mines, though some individual modules have been in use in many mines as Terrock tools. A couple of mines have been able to take advantage of these blasting solutions. This is convenient since it can be used by medium and smaller operations to improve results and control adverse impacts.

The Integrated Mobility solution provides an important on-site blasting tool.

 

ACKNOWLEDGEMENTS

 

This is to acknowledge collaboration and discussions with Mr Alan Richards and Mr Adrian Moore of Terrock Consultants. Also acknowledged is the use of MobileSmith™, an enterprise-class, flexible mobile app development platform that enabled the quick development of the mobility solutions for the development of mobile application. The support of the software development team at Earth Resource Technology/ Continuous Excellence is acknowledged for their hard work.

 

REFERENCES

 

Akella, J, Kubach, T, Löffler, M and Schmid, U, 2008.Data-drivenManagement: Bringing More Science into Management (McKinseyTechnology Initiative Perspective).

 

Bhandari, S,  1997.  Engineering  Rock  Blasting  Operations,  370  p (A A Balkema Publishers: Rotterdam).

 

Bhandari, S, 2011. Information management for improved blastingoperations and environmental control, presented to Third Asia- Pacific  Symposium  on  Blasting  Techniques,  Xiamen,  10–13August. 

Bhandari, S and Bhandari, A, 2006. Blast operations informationmanagement system, Journal of Mines, Metals and Fuels, 54(12). 

Cunningham, C V B, 1983. The Kuz-Ram model for prediction offragmentation from blasting, in Proceedings First International Symposium on Rock Fragmentation by Blasting, Luleå, August,pp 439–454. 

Cunningham, C V B,1987. Fragmentation estimates and the Kuz-RamModel – four years on, in Proceedings Second International Symposium on Rock Fragmentation by Blasting (eds: W L Fourney and R D Dick),pp 475–487 (Society for Experimental Mechanics: Bethel). 

Engin, I C, 2009. A practical method of bench blasting designfor desired fragmentation based on digital image processing technique and Kuzram model, in Proceedings Ninth International Symposium on Rock Fragmentation by Blasting (ed: J A Sanchidrián), pp 257–263 (Taylor and Francis Group: London). 

McHattie, L, 2013. Advances in mine engineering to enableinformation mobility for ‘intelligent mine’, presented to ISARC 2013, The 30th International Symposium on Automation and Robotics in Construction and Mining, Montreal, 11–15 August.

Parihar, C P and Bhandari, S, 2011. Improving blasting operationsusing data management and analysis, in Proceedings Tenth International Symposium on Rock Fragmentation by Blasting 

(eds: P K Singh and A Sinha), pp 403–409, (CRC Press: Boca Raton). 

Richards, A B and Moore, A J,1995.Blast vibration control by wave frontreinforcement techniques, in Proceedings Explo 1995, pp 323–327  (The Australasian Institute of Mining and Metallurgy: Melbourne). 

Richards, A B and Moore, A J, 2004. Flyrock control – by chance ordesign, in Proceedings 30th Annual Conference on Explosives and Blasting Technique (International Society of Explosives Engineers:Cleveland).