Vickers microhardness (MH) of coal is known to be strongly correlated with coal rank. To examine coal rank and other coal quality parameters, such as organic sulfur, that might influence MH, a suite of more than 300 samples from the Penn State Coal Quality database with vitrinite Rmax < 1.1 % were examined. The data set was narrowed down to 296 coals with moisture (as-received basis) < 20 %. As MH is a parameter measured on vitrinite, vitrinite Rmax was used as the rank parameter. The Eocene Big Dirty coal (Washington state) stood out as a high MH/high-moisture coal while Hanna and Green River basin coals (Wyoming) had low atomic H/C values and K Unita Basin (Utah) coals had high H/C. Organic S did not show a correlation with MH within discrete rank ranges. With respect to vitrinite Rmax vs. MH, the Big Dirty coal and some Illinois and Iowa coals lie on the high-MH/low-Rmax side and the Pennsylvanian Tioga (West Virginia) and the Indiana Brazil Formation coals, all dominated by dull lithotypes, lie on the low-MH/high-Rmax side of the main data trend. Overall, the quadratic regression of vitrinite Rmax vs. MH yields an R2 of 0.55, indicating a significant correlation at the 95 % level.

中文翻译：

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次烟煤和高挥发性烟煤的维氏显微硬度异常


众所周知，煤的维氏显微硬度 （MH） 与煤等级密切相关。为了检查可能影响 MH 的煤等级和其他煤质参数，例如有机硫，检查了宾夕法尼亚州立大学煤炭质量数据库中的一组 300 多个样品，其中镜质体 Rmax < 为 1.1%。数据集缩小到 296 个含水量（收货基础）< 20 % 的煤。由于 MH 是在镜质体上测量的参数，因此使用镜质体 Rmax 作为秩参数。始新世 Big Dirty 煤（华盛顿州）作为高 MH/高水分煤脱颖而出，而汉纳和格林河流域煤（怀俄明州）的原子 H/C 值较低，K Unita 盆地（犹他州）煤的 H/C 值较高。关于镜质体 Rmax 与 MH，Big Dirty 煤以及伊利诺伊州和爱荷华州的一些煤位于高 MH/低 Rmax 一侧，宾夕法尼亚州的 Tioga（西弗吉尼亚州）和印第安纳巴西组煤都以暗淡的岩型为主，位于主要数据趋势的低 MH/高 Rmax 一侧。总体而言，镜质体 Rmax 与 MH 的二次回归产生 R2 为 0.55，表明在 95% 水平上存在显著相关性。