Materials properties of barricade bricks for mining applications

Barricade bricks are fundamental to the safe operation of a mining site. Past failures have lead to loss of life and reduced mine efficiency or even shut down. The fundamental material property that determines the operational characteristics of barricade bricks is their permeability, which must be tailored to suit the operational environment of the mine. The ability of the barricade to control the hydraulic pressure within a stope application is crucial for safety and economic returns. In the current work practical barricade bricks were tested for permeability. As well, the strength and modulus of bricks were measured after being soaked in water for either 7 or 90 days so that a measure of their engineering functionality could be determined. The primary conclusions of this work are as follows. There was substantial deviation in permeability between bricks; however, the average permeability of the barricade bricks was several orders of magnitude larger than the values obtained for the hydraulic fill. This difference indicates that modelling efforts can assume that the barricade does not contribute to the pore pressure development within the fill. Hence the drainage of the system is not related to the permeability of these bricks provided that the barricades are built from the bricks in such a way that the construction or future migration of fines from the fill does not impede the drainage performance.

从"障塞"一词看海上丝路的起始年代

针对 2 0 0 1年“海上丝绸之路与南方大港学术研讨会”上 ,许多学者认为《汉书·地理志》中“日南障塞”的“障塞”是军事要塞、军事屏障 ,并据此推导出海上丝绸之路徐闻开港时间是汉武帝元鼎六年 (公元前 1 1 1年 )的观点 ,认为 :“障塞”只是一个普通的动词 ,是阻塞不通的意思 ;徐闻的开港时间也不是元鼎六年 ,而是元鼎六年之后、汉元帝之前 ,即大约公元前 1 1 0年—公元前 1年之间