The Excavating Stability Study of a Power Station Underground Plan

In this study, rock stability psychoanalytic theories were concluded, excavation of the underground workshop were done by applying geotechnical common software FLAC3D, then the adjoining rock displacements and transformation rules were simulated and study, and then bolts were used to support the rock, with the study of stress and strain rules and we can analyze and evaluate the effects of the bolting.

Laws of Formation and Evolution of Pressure Arch in Coal Mining Adjoining Rock

Based on numerical simulation of computing Software ANSYS, the curve of arching coefficient variation of pressure arch due to actual mining was analyzed aiming to a special mining face, the law of stress transfer and change in surrounding rock was discussed, and the evolving features and characteristics of pressure arch was obtained. The analysis and discussion show the following facts: Arch body will become thicker and stress in the arch body increases with working face’s driving distance increasing; the morphology of pressure arch transits from ellipsoid with long axis in the vertical direction to ellipsoid with long axis in the horizontal direction along the trend of working face; along the tendency of working face, the morphology of pressure arch is a ellipsoid with long axis in the vertical direction.

III.—The Sudbury Nickel-Ores

In Professor Gregory's interesting presidential address contained in your journal for October, there is a reference to the origin of the Sudbury ores, in which he expresses the opinion that they were deposited from solution long after the first consolidation of the rocks with which they are associated. As the Sudbury ore deposits are perhaps the best examples in the world of the magmatic segregation of sulphide ores it seems a pity that the weight of Professor Gregory's authority should be given against the correct view. Probably he has not read the reports on the region by Dr. Barlow and myself in which incontrovertible proof of the magmatic origin of these ores has recently been given. In the report prepared by myself it is shown that all the ore bodies are found at the lower edge of a laccolithic sheet of norite, blending upwards into micropegmatite, or on dike-like projections from this sheet. The laccolithic sheet is 37 miles long, 17 miles wide, and has dozens of ore bodies connected with its basic edge. The adjoining rock may be granite, gneiss, green schists, graywacke, etc., without affecting in any way the monotonous character of the ore. The ore bodies may contain fragments of the adjoining rocks and sometimes also of the norite, for some crushing and faulting has taken place; but everywhere the solid ore passes into pyrrhotitenorite, and then into norite spotted with blebs of ore. The sulphides have sharp boundaries against the adjoining rocks, but blend into the norite.