The starting operations of the construction material of the quarry of Aircore Drilling are carried out by means of drilling and blasting processes. Currently four to five blasts are carried out per month, this activity being essential for the development of mining in the field.
Currently, the drilling and blasting passports used were designed considering certain parameters and taking into account the characteristics of the deposit to carry out blasting with two or three specific explosives. The drilling and blasting works are contracted to the company Aircore Drilling in Western Australia, which performs the start-up tasks.
Aircore Drilling has the mission to carry out blasting with the required quality, has established a quality management system to carry out blasting that meets the requirements of its blasting procedures. This procedure states that the company’s operations specialist, together with the UEB specialist or technician that provides the blasting service, must control the completion of the process. The control of the blasting service must be carried out through the following policies:
Control of the quality of the drilling service as a previous step to the blasting service (drilling passport). Control of compliance with the drilling-blasting passport. Control and determination of the amount of explosive and means of explosion required for each blasting service.
Measurement of the effectiveness of the process with periodicity. Daily practice shows that this procedure is not fully met and therefore the results of fragmentation present the required quality and the presence of oversized rocks far exceed 10%,
The drilling works are carried out based on the guidelines of the administrative management and the technical staff of the quarry as established in the current contract with the artillery and the company Aircore Drilling.
On our part we do not have a copy of updated topographic documentation of the quarry and the mining plan, thus subtracting knowledge about the real height of the exploitation banks, which is why we believe that drilling work has sometimes been carried out ignoring the real heights of the bank and the depth that the drilling holes must have, which has led to improprieties in the operation of drilling the rocks and the appearance of on the floor of the banks, in addition to irregular and convex slopes, as can be seen in figure 1.0.
Considering the parameters established by the companies in the design of the drilling and blasting passport, there is a good work when it comes to putting them into practice in the rock mass.
The parameters that are presented in the exploitation reports and the Passport made by the technician in the quarry are not considered by the operator when drilling and loading the explosive in general.