In these series article, we will introduce the key knowledge on blast drilling according to our many years practical experience in Hardrock Drills.

Below is the lecture overview which will be introduced item by item, today we will start from Modern systems for surface blasting drilling.

Lecture Overview

  • Modern systems for surface blasting drilling
    • Blast drilling control equipment Blast Metrix
    • Borehole drilling surveying
    • Inclination
    • Depth measurement
    • VOD control
    • Vibration
  • Typical deviations between planning and realization in rock blasting
  • Practical surface blast layout planning

Modern systems for surface blasting drilling

Planning of a blast drilling

  • General Considerations
    • What is the goal of my blasting drill work?
      • eg.: high comminution or just breaking the rock in order to transport it?
    • What are the surrounding conditions?
  • First thing to do: evaluation of geology
  • Prior to every blast:
    • Each blast has to be planned separately
    • the drill rig operator and the blaster should define the blast site together
  • State of the art: computer based blast planning
  • Recommended: building up a database for the whole process “drilling and blasting
    • Save data as evidence
    • Learn from prior blast
    • Young engineers who are responsible for the blasting work have a basis to work on

Surveying of the face

  • 3 systems available:
  • Theodolite with distance-meter
    • Easy to handle system
    • Produces only a very imprecise picture of the face
  • Laser scanner
    • Very precise
    • High investment costs
    • Huge amount of data to deal with and save somewhere
    • Time intensive
  • Photogrammetry
    • Fast Cheap
    • Precise enough for our needs
    • Uses a real picture







Borehole drilling









Automation in drilling

  • Control System
    • Hydraulic controls replaced by electric controls (30% less hydraulic components, less noise)
    • Anti-jamming function
  • AutoRAS
    • Drilling of holes to predefined depths (by spanning up a laser plane)
    • ROC Manager (blast planning) and MWD (measure while drilling)
  • GPS and HNS
  • Silenced version for urban areas

Control of drill work

  • Measure borehole position (using theodolite and a mirror)
    • Analysis for example with AutoCAD
  • Measure distance between holes with a measuring tape
  • Measure borehole deviation
  • 3 systems available
    • MDL Boretrak
    • Transtronic
    • Pulsar

Charging of blast holes – kind of explosive

  • Kind of explosive has to be adapted to type of rock
    • Nitroglycerin based explosives – most times for initiation
    • Detonating cords – for initiation and contour blasting
    • ANFO (Ammonium nitrate fuel oil) – not detonator sensitive
    • Watergel explosives (slurries) – AN+glasprills+water+TNT – not detonator sensitive
    • Emulsion explosives – water in oil emulsion – detonator sensitive
    • Heavy Anfo – mixture of Anfo and Emulsion

Charging of blast holes – detonator

  • Most commonly used: electric detonator
  • State of the art: NONEL and electronic detonators









Charging of blast holes – Initiation

  • Ideal blasting column
  • Covering of holes
  • Right stemming

Control of blast borehole

  • Make sure all boreholes detonated completely
  • Evaluate the blast
    • Muck
    • Comminution
    • Possible back break

Environmental effects – Dust/blasting fumes

  • Avoid dust/blasting fumes
    • Right stemming
    • Choose right explosive
    • Right initiation
    • Make sure holes detonate completely
    • Also: water the muck pile

Environmental effects – Noise

  • Stay clearly below 120 dB (threshold of pain)
    • Initiation from borehole bottom
    • Avoid using detonating chords (if you do: cover sufficiently)
    • Use of right stemming material

Environmental effects – Vibrations

  • Regular measurements and documentation of results
    • For own vibration prediction
    • As evidence for authorities
  • Stay within predefined limits


  • Save all gathered data on
    • face surveying
    • blast plan borehole position
    • borehole surveying
  • Film and take pictures of the blast – also a cheap evidence
  • Save all measured data on noise and vibration

Above is the brief introduction for Modern systems for surface blasting drilling, flowing blogs will continue introduction on below two topics

  • Typical deviations between planning and realization in rock blasting
  • Practical surface blast layout planning

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