Why is mining like the Star Wars movie?
Published: Monday, May 29, 2017 3:36pm
Sometimes, in the theatre of my mind, I have this opening sequence play out:
because of a situation that reminded of a problem previously experienced. The scenario is an underground Mine in central Africa, 35 years ago, where I had been told that my product was not up to the job. On inspection I found that at least 20% of the holes were missing but more interesting was the 9 hole burn cut in this particular air leg heading.
In those days it was standard to issue the driller with a metal grid designed to assist in the accurate drilling of this burn cut. It looked an Alliance’s fighter jet, with the guide pole standing out in the front and 8 thrusters i.e. welded pipes in a matrix approximately 200mm long, configured at the rear to guide the subsequent holes. When we inspected the face it was obvious that this driller hadn’t used his guide (when asked he did eventually find it, 70m back from the working face and it looked more like wet spaghetti than a jet fighter). We asked that he place it in the hole and then put his 2nd drill steel into any one of the guides. He could not even get the guide into the first hole of the cut, his hole being so twisted from his poor drilling. When asked why he did not use the guide his response was classic: “I did but the ground must have moved since I started to drill.”
Now, a jump through the space-time continuum and we find ourselves on a Mine in 2017 trying to do a triple pre-split in order to sharpen up the pit angle. Holes are 115mm on a 1.2m spacing and the first 70° bench has 12 to 13m holes with a 26mm pre-split.
Without even beginning to analyse the explosives/rock ratio, the area that stood out was the accuracy of the drilling. The first visit had identified the interesting matrix (maybe this should read bird’s nest) of half barrels that were left behind when they were still visible. Unfortunately, the drilling contractor was being paid by the metre and not the quality of the end result so a 4° deviation was not a problem, as far as he was concerned. At an average depth of 12.5m, this would be a ± spread of 0.875m. Even with the focus on his drilling accuracy, a subsequent visit revealed collaring distances of 0.9m to 1.6m.
The pre-split was not giving them the results they had anticipated.
History repeats itself. Fortunately, in both cases, the Mine realised that the power of their explosives could not overcome the inadequacies of the drilling.
Being a supplier to the Mining industry often has one looking outside the box to identify the likely causes of a situation. This should lead to an honest evaluation if one wants to get to the root cause of the issue, even if the answer is not what we or the customer want to hear. One of our 4 Core Values is Trust and it is built from being honest.