Due to unstable sea level, drilling by using 6bs countercirculation pump is not very suitable.
在浅海岸边进行钻机作业，由于海平面水位不稳定，采用6 BS反循环泵已不合适。
2
Some superiorities of using down hole hammer countercirculation type continuous coring (sampling) method in gold ore exploration are expounded in this paper.
文中阐述了在金矿勘探中应用潜孔锤反循环连续取心（样）的优越性；
3
The method of design of arbitrary cany counter of unnatural sequence circulation by use of medium - scale counter core is discussed. It finds wide application in the special circulationcounter.