First-Order-Second-Moment Analysis of Reliability in Predicting the Rate of Penetration

Summary :To date, given the importance of drilling operations in the mining process and its impact on other phases of extraction, a number of studies have been carried out to investigate the influence of predicted bit rate and to determine the parameters influencing it. The estimation of rate of penetration (ROP) is an integral part of the design and planning stages of a mining project. To achieve a reasonable estimation of the ROP in the rock, it is essential to identify the influential factors, measure the effectiveness, and calculate the uncertainty of each set. The factors examined in current study include thrust, rock mass characteristics including rock mass indices, uniaxial compressive strength of intact rock, Schmidt hardness. Conducting a field study and laboratory testing, a database was compiled from the above parameters in Irankuh mine. Among these parameters, Schmidt hardness has the lowest standard deviation and highest reliability index and thrust has the highest standard deviation and lowest reliability index. This result indicated that in the independent parameters, Schmidt hardness has the lowest and thrust has the highest level of uncertainty. The standard deviation and reliability index of experimental models presented for the (ROP) are also at 53.02 and 0.729 percent respectively. So this relationship to predict the (ROP) in the lead and zinc Irankuh mine is confidence.
In this research, the necessary parameters to predict the drilling speed were selected in order to examine the effect of different geological, geo-mechanical and operational parameters of the drilling machine on ROP and prediction of the performance of the drilling machine. The model was obtained from effective parameters for the penetration rate. In the following, the reliability rate of the obtained model was calculated for the rate of permeability of drilling-bit in Irankouh mine to examine the uncertainty rate.
Methodology and Approaches : The first-order second-moment method has the calculations that are relatively simple, and only the information needed to calculate it, is information related to the moments of the input variables, so this method has been used in this research.
Results and In this research, there is an uncertainty in registered information due to the environment to conduct the field observations and surveys and laboratory tests. Therefore, there is uncertainty and ambiguity in the developed equation to calculate the penetration rate in the Irankouh mine. So it has been tried to calculate the amount of ambiguity and, in fact, the number of variations that indicates the dispersion around the actual value of the penetration rate, using reliability analysis to FOSM first-order-second-moment method.