Abstract: A method of reusing a slurry in a ground improving method, wherein a hardening agent is injected into the ground, and wherein the muddy water (i.e., the slurry which is discharged) upon working is regenerated and again used as an injection material; namely, a hardening agent. By measuring the physical amount indicative of the permeability characteristic of the hardening agent contained in the slurry, an amount of hardening agent contained in the collected slurry (i.e., an amount of hardening agent to be collected) is calculated. Since the amount of collected hardening agent is calculated simultaneously with the collection of the slurry, the amount of hardening agent to be newly injected can be controlled in a real-time manner on the basis of the latest data (i.e., numerical value).

Abstract: Disclosed is a vertical roller mill wherein a material fed to a casing is ground between a rotary table and a plurality of grinding rollers which are pressed against the rotary table and are rotated as the rotary table is rotated, the ground material being entrained by the upblast of heated gas or the like and discharged out of the casing. A bracket extended above the rotary table for carrying the grinding roller is pivoted at the side of the casing, and a pull-down means is connected with the bracket adjacent to the part thereof at which the grinding roller is supported. The bracket is pulled down by the pull-down means so that the grinding roller may be pressed against the rotary table.