Abstract Bituminous coals are still the main source of energy in the world. However, these brittle porous materials are prone to crushing under action of industrial tools. Our early depth-sensing nanoindentation tests of bituminous coals showed that even if the depth of indentation is within the nanoscale, these brittle coals are no longer continuous elastic media within the indentation zone but rather fine powders of crushed particles irrespectively to the coal maceral. Dust formation of the materials is a problem of great practical importance for the mining industry. Indeed, the powders of coal particles formed during crushing may cause not only explosions in mines but they also contaminate the environment around the roads of the coal transportation. In this study, the crushing of coals due to action of rigid conical indenters and formation of small coal particles is investigated. The studies are based on development of the Galanov-Grigoriev (GG) model of crushing of brittle porous materials and the model adjustment to specific features of coal fracture. Using the indentation tests, we estimate the size distribution of the dust particles formed within the region of fully crushed material. Results are presented for coals of three different stages of metamorphism.

中文翻译：

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烟煤压痕：断裂、破碎和粉尘形成

摘要 烟煤仍是世界能源的主要来源。然而，这些脆性多孔材料在工业工具的作用下容易被压碎。我们对烟煤的早期深度传感纳米压痕测试表明，即使压痕深度在纳米级内，这些脆性煤在压痕区内不再是连续的弹性介质，而是与煤质无关的粉碎颗粒的细粉。材料的粉尘形成对采矿业具有重要的实际意义。事实上，在破碎过程中形成的煤颗粒粉末不仅可能导致矿井爆炸，而且还会污染煤炭运输道路周围的环境。在这项研究中，研究了由于刚性圆锥压头的作用和小煤颗粒的形成而对煤的压碎。这些研究基于对脆性多孔材料破碎的 Galanov-Grigoriev (GG) 模型的开发和对煤裂缝特定特征的模型调整。使用压痕测试，我们估计了在完全压碎的材料区域内形成的灰尘颗粒的尺寸分布。给出了三个不同变质阶段的煤的结果。