USA - SIGNIFICANT VIBRATION REDUCTION in a quarry environment

29/06/10

CONTEXT                                                                                                        

1. STS provides advanced technical services to the drilling, blasting, construction and mining industries in the U.S.
   

2. STS customer in this case: a quarry in Virginia. STS has a successful track record in other sites of the group.
   

3. Previous shots at 6-10 inches in this part of the quarry close to power lines (<150 feet)
   

CHALLENGE                                                                                                       

1. Reduce vibration below 2.00 in/s at close power lines (less than 150 feet)
   

2. Shoot full column, 74 feet face
   with 6.5 inch holes
   and no decking
   

3. Quarry management stipulation that STS could NOT do a signature hole

METHOD - PROTOCOL

1. I took one of their blasts from two years ago (with digital dets) and a seismic waveform,
   

2. I entered all the data including some very detailed rock info that the quarry got for me
   

3. I “deconvoluted” the signature hole based on the blast using DNA-Blast software corresponding module
   

4. I shot the second shot at the Quarry using the Derived Signature Hole Waveform.
   

RESULTS

1. Shot 1 (April 13): Seismograph readings reduced by 50% (From over 9.00 in/s to 4.26 in/s
   

2. Shot 2 (June 16): I re-analyzed the data using the seismograph info from shot 1 and the shot today: the readings were reduced another 50% from before and this shot was closer and more holes.
   

3. Blasting is now routinely performed and more reserves accessed due to the fact that vibration is well controlled.