Proper confinement of a blast is essential to minimize adverse effects. For instance, if a blast is heavily confined, excessive ground vibrations may result. On the other hand, if a blast is under confined, excessive airblast or flyrock may result. Burden and spacing influence confinement.
The Burden / Spacing Comparison graph displayed on the Spacing tab identifies an optimum zone for confinement. The two reference lines indicate the "safe" range. Data points above the S=2B reference line represent blasts that were under-confined. Blasts below the S=B reference line represent blasts that were heavily confined.
Take a look at the graph generated from our ongoing example— SkyHavenCompleted.xls. If you did not create this file, open this version now. Then, click the Spacing tab along the bottom edge of the worksheet.
Using the SkyHavenCompleted.xls, answer the question below. Note: None of the quizzes in this course are recorded in any way.