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Stemming Performance Study

DBA Consulting conducted this study to quantify the effectiveness of VARI-STEMĀ® using Different Types of Top Stemming Material.

The primary result of the test was that VARI-STEM plugged holes all yielded retention times at least 2 times longer than non-plugged holes. The average retention time for crushed stone stemmed (non-plugged) holes was 39 ms, for VARI-STEM with crushed stone 120 ms, and for VARI-STEM with sand drill cuttings (fines) 145 ms. This test indicates our plugs with sand drill cuttings out performed crushed stone stemming alone. The STUDY_ALIAS_01 and the Varistem Videos used drill cutting chippings.

Just think of the potential cost savings! Quarries, contractors and blasters could potentially eliminate, or at least reduce, the volume and expense of crushed stone stemming, allowing them to use less expensive drill cuttings for stemming.



The following video was filmed in September 2003 during our Stemming Performance Study by DBA Consulting.


Stemming Performance Study Video [High Bandwidth Connection - 22mb]

Stemming Performance Study Video [Low Bandwidth Connection - 2mb]

This video is compatible with windows media player 7 and above. If you cannot see this video, please visit either Download.com or Microsoft.com for a newer version of this player.


As you view the video, please pay particular attention to the difference in stemming retention between the left side of the shot vs. the right side of the shot.


Left side of video

  • 39ms = Average retention time of crushed rock, stemmed holes
    (no VARI-STEM)

Right side of video

  • 120ms = Average retention time of VARI-STEM with crushed rock
  • 145ms = Average retention time of VARI-STEM with sand consistent drill cuttings


Also please note the more pronounced, deeper Energy Trough. The trough extends deeper towards the toe of the wall on the right side of the shot where our VARI-STEM Plugs were used.  A deeper energy trough results in better diggabilty.






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