Precision Blasting with AI
At the Navi Mumbai International Airport site, a cutting-edge collaboration used AI-powered drone surveys and high-energy explosives to improve rock fragmentation, reduce oversize, and enhance blasting efficiency during excavation.

Navi Mumbai International Airport (NMIA) project is an under construction greenfield project in Panvel area. At present, pre-construction works i.e., blasting and excavation to level the terrain is ongoing. Based upon the rock type and location, the blasted rock is either crushed for construction aggregates or used for filling activities at the airport construction sites.

The existing blasting practice involves use of slurry explosives in the cartridge form, in conjunction with non-electric detonator and occasional use of electronic detonator. Site team from (IMMUNITY GAURAV BK — joint venture) IGBK expressed the need for a solution to improve fragmentation and reduce oversize (> 500 mm rock size) to control the need for secondary breaking before the blasted rock could be fed to the in-pit crushers.

Technical solution
Smartchem Technologies (STL) & IIT Dhanbad (ISM) worked with IGBK at site to use state of art drone-based Al technique for fragmentation study of blasts conducted with Optimex LDAN (low density ammonium nitrate) based high energy explosive (HEE) cartridges namely BELOX. Typically, with 33 per cent more energy than slurry explosives, HEE cartridges were proposed as a solution to effectively address the fragmentation distribution concerns. With higher proportion of heave energy in HEE, the muck movement was also expected to be more as compared to that of slurry-based explosives. Additionally, HEE with a density of 0.82 to 0.84 g/cm3, offers better charge distribution in the hole, bringing down the charge factors (kg/m3).

Three-dimensional (3D) model of every blast patch was created to analyse the real time confinement of the explosive energy based on actual location of drill holes. The blasts were then recorded with high-speed camera to corelate the observations with pre blast analysis. 

Methodology
  • A total of nine baseline blasts with existing practices were observed for fragmentation distribution [D80 (particle size where 80 per cent of blasted rock is smaller than that size) and % rock below 500 mm].
  • Six blasts with HEE were conducted in different areas of the site [close to the baseline location]
  • For every blast, a pre blast drone survey of the bench was carried out to prepare the 3-D models
  • The hole positions were automatically detected during the image processing on the Al based platform. 
  • The models were analysed for explosive energy confinement, drill collar accuracy and burden reliefs
  • A post blast drone survey of the blasted muck was carried out to profile the muck movement and the fragmentation
Observations
The blast result was analysed through fragmentation analysis in the same location with similar geology for accurate comparison. The fragmentation with HEE was recorded better as compared to that of with slurry explosive. Further the % of imaged rock below 500 mm (crusher max feed size) was 3.51 per cent higher in HEE blasts as compared to the baseline results. To limit biases in the photometric measurements, all fragmentation data for the blasted muck pile was collected immediately after the blast. Therefore, fragmentation studies were based on the surface area of the muck pile visible during drone aerial survey. The analysis is based on the rule of thumb that, geology apart, fragmentation is coarse near collar than as we go deeper into blasted muck which had direct access to the explosive energy.

Result
The key outcomes of the trials recorded were the fragmentation and linear distribution of explosive charge (kg/m). The conclusions reached from the trial blasts were:
  • D80 of the trial blast done with HEE was improved by 12 per cent as compared to existing slurry explosive.
  • % of particle under 500 mm size with HEE was increased by 3.51 per cent as compared to existing slurry explosive
  • Blast nuisances like fly rock, ground vibration were under control
Acknowledgment
Smartchem Technologies Limited sincerely acknowledge and appreciate the support rendered from the IGBK management, Navi Mumbai Airport for conducting trials. We would like to thank Shreekanth Pavin (Project – Head), Praveen (Blasting In-charge), the entire blasting team for all the valuable support provided during Trials.

We would also like to extend our sincere thanks to IIT Dhanbad (ISM), an educational institute of global repute, for their association in the study through necessary equipment support, supervision of trials and evaluation of the trial results.

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