Advances in Civil Engineering / 2019 / Article / Fig 9

Research Article

Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi

Figure 9

Microscopic images of Mchenga arkose sandstone (a, b, c, d) and Mchenga fine-grained sandstone (e, f, g, h). Qz: quartz; Kf: orthoclase; Pl: plagioclase; Bi: biotite; Mf: mafic minerals; C: coaly substances; Cb: carbonate minerals; (·): pseudomorphism; FP: fracture. Widths of the images are 6.0 mm for (a), (b), (e), and (f); 2.5 mm for (c) and (d); and 1.2 mm for (g) and (h).