The study compares the drilling performance of Kymera and PDC bits in salt formation using River and Delta State Continental Shelf of Nigeria as a case study. The measurement while drilling (MWD) and the logging while drilling (LWD) methods were used to measure the real time well drilling operation. well formation and drilling statistics. The data obtained from the Ogbaimbiri. Ossiomo. Utorogu and Okporhuftu wells have the penetration rate of 6.2 m/hr. 5.9 m/hr. 12.2 m/hr. 6.3 m/hr for Kymera bit and 4.2 m/hr. 3.4 m/hr. 6.8 m/hr. 3.9 m/hr for PDC bit respectively. The pearson correlation coefficient has a value of r = 0.897. n = 4. p<0.05 and r = 0.784. n = 4. p<0.05 for both kymera and PDC bits. The results established a strong and positive correlation between the penetration rate and distance drilled in each bit. It also shows that the higher the penetration rate the more the distance drilled by each bit. The study concluded that the Kymera bit was more efficient as it was able to penetrate the different formations with a lesser time and at a greater penetration rate.

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Journal homepage: www.zums.ac.ir/jhehp Background: The release of lead dust during the processing of lead-gold ore has become an environmental threat. Therefore the protection of miners' health and their environment required remediation which can be achieved by ranking the risk posed by lead in order to prioritize the allocation of resources during remediation. Methods: Soil and water samples were collected at BRC, BRG, BVC, BPA and BFA; BWE, BBH and BPO using stratified random and grab sampling methods. Lead concentrations in the samples were determined using AAS while health risk index (HRI) via ingestion was estimated using USEPA equations. The ranking of HRI was done using Detailed Quantitative Risk Assessment while the difference between the HRI and USEPA standard were determined using one sample t test. Results: The result showed that BRC/10, BRG/03, BVC/11, BPA/02 and BFA/08 were ranked highest in soil samples, while BWE/02, BBH/09 and BPO/04 were ranked highest in water samples as they posed elevated health risk effects to miners. One sample t test established that the BRC, BPA, BFA and BPO were significantly different from United States Environmental Protection Agency (US EPA) standard. Conclusion: The study discovered that the users of both the lead contaminated soil and water were seriously exposed to potential health risk. It therefore suggested that decision makers should give priority in allocating resources to those sites with elevated lead concentrations during the remediation.