The inter-row delay timing plays a pivotal role in any blast round as it not only influences the mechanism of fragmentation, but also offers a vast potential in improving the overall results of fragmentation. It is in this perspective that the current study presents a comparative investigation of the influence of inter-row delay timing on fragmentation in two different strength sandstone formation in large-scale, multi-row blast rounds of a two surface coal mines in India. The investigations are based on full-scale field blasts. The study highlights the role of p-wave velocity and brittleness vis-à-vis impedance to shock wave propagation during the initial as well as final stages of rock breakage. Given this, the role of shattering effect (in stronger sandstone formations) and heaving effect in weaker strength sandstone has been clearly established in the rock breakage mechanism. Furthermore, the study also suggests that for weaker sandstone, longer inter-row delay timing (15-25 ms/m of effective burden) yields the best fragment size results. Similarly, for stronger sandstone formation, shorter inter-row delay timing (10-17.85 ms/m of effective burden) yields the best fragment size results.

中文翻译：

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行间延迟时间与高砂岩台阶上某些岩石特性的比较研究

行间延迟时间在任何爆炸回合中都起着举足轻重的作用，因为它不仅影响片段化的机制，而且在改善片段化的整体结果方面具有巨大的潜力。正是从这个角度出发，目前的研究对印度两个露天煤矿的大规模，多行高炉爆破中两个不同强度砂岩地层行间延迟时间对破碎的影响进行了比较研究。调查是基于全面的现场爆炸。该研究强调了在岩石破裂的初始阶段和最终阶段，p波速度和脆性相对于阻抗对冲击波传播的作用。鉴于这种，岩石破碎机理中已经清楚地表明了破碎作用（在较强的砂岩地层中）和起伏作用在强度较弱的砂岩中的作用。此外，研究还表明，对于较弱的砂岩，较长的行间延迟时间（15-25 ms / m的有效负荷）可产生最佳碎片尺寸结果。同样，对于更强的砂岩地层，更短的行间延迟时间（有效负荷的10-17.85 ms / m）可产生最佳碎片尺寸结果。