The blasting machine must have a robust and closed enclosure
All parts of the blasting machine must be undetectable
The design must complicate unauthorized operation
electrical requirements
The blasting machine must have massive connection terminals. They must not be hollow and the diameter must be a minimum of 4mm. Protection against touching electric shock must be given.
Between the terminals there must be an isolation barrier that overtops the connection surface for at least 8mm.
Isolation between electrical parts and the housing must be at least 1000V or the double working voltage.
Isolation parts must comply with the state of the art
Capacitor blasting machines have to ensure that the capacitor is discharged after blasting.
An interlock must ensure that triggering is only possible if the full electrical power (energy) is available.
performance
type A
After 1ms the current must reach at least 1A. From the beginning until falling below 1A, the impulse must be at least 4mWs/Ω.
limiting resistance
10 ignitors
60Ω
20 ignitors
110Ω
30 ignitors
160Ω
50 ignitors
260Ω
80 ignitors
410Ω
100 ignitors
510Ω
160 ignitors
810Ω
200 ignitors
1010Ω
type U
After 1ms the current must reach at least 2A. From the beginning until falling below 1.5A, the impulse must be at least 18mWs/Ω.
limiting resistance
10 ignitors
55Ω
20 ignitors
90Ω
30 ignitors
125Ω
50 ignitors
195Ω
80 ignitors
300Ω
100 ignitors
370Ω
160 ignitors
580Ω
200 ignitors
720Ω
type HU
After 1ms the current must reach at least 30A. From the beginning until falling below 15A, the impulse must be at least 3.3Ws/Ω.
limiting resistance
20 ignitors
15Ω
80 ignitors
50Ω
160 ignitors
100Ω
other requirements
In regard to protection against firedamp the blasting machines must comply to the state of the art.
The ignition current pulse must not be longer than 4ms. After triggering the recharging of the capacitor, triggering a second pulse must be impossible.
Blasting circuit continuity tester
general requirements
The current source must not be accessible
The voltage of the current source must be lower equal 12V
The test current must be less than 25mA
There must be protection resistors to limit the current in a single failure case to 50mA
special requirements for Ω–meters
The accuracy must be 1.5% of the full range
The zero point should be regulated
A 10% deviation of the current source voltage must not influence the measurement accuracy
AUSTRIA: Regulation for blasting for mining
Very similar to the GERMAN version.
Between the terminals there must be an isolation barrier that overtops the connection surface for at least 8 10mm.
A performance sheet must be on the housing
type description
manufacturer and manufacturing site
site number
manufacturing date
limiting resistance
blasting voltage and capacitor capacity
US: eCFR / Title 30 / Chapter 1 / Subchapter K / Part 56 / Subpart E / Electric Blasting
Shunting
Except during testing —
Electric detonators shall be kept shunted until connected to the blasting line or wired into a blasting round;
Wired rounds shall be kept shunted until connected to the blasting line; and
Blasting lines shall be kept shunted until immediately before blasting.
Firing devices
Power sources shall be capable of delivering sufficient current to energize all electric detonators to be fired with the type of circuits used. Storage or dry cell batteries are not permitted as power sources.
Blasting machines shall be tested, repaired, and maintained in accordance with manufacturer's instructions.
Only the blaster shall have the key or other control to an electrical firing device.
Circuit Testing
A blasting galvanometer or other instrument designed...