Mine Shaft Rehabilitation Grouting-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes a grouting program to reduce water inflow into a production shaft at a U.S. salt mine. The conventionally sunk, timber-cribbed shaft is unlined to 1,900 feet and has four compartments. A subhorizontal discontinuity was causing an 11-gallon-per-minute inflow, contributing to a total inflow of 32 gallons per minute.<br /><br />The design used two rings of boreholes around the shaft: 28 in the outer ring and 22 in the inner ring, each divided into primary and secondary holes. Angled upholes were intended to intersect the water-bearing feature at least 10 feet beyond the shaft walls. Hole collars were positioned to avoid earlier work.<br /><br />The sequence began with surveying and installing grouted standpipes. Outer-ring primary holes were drilled to intercept and drain the water-bearing feature. While drainage continued, inner-ring primary and secondary holes were pressure-tested and grouted with polyurethane. The outer-ring holes were then sealed using ultrafine cementitious grout, with acrylate watergel as an alternative. Finally, the outer holes were abandoned and backfilled with neat cement grout.<br /><br />The work used slide and jackleg drills, polyurethane pumps and packers, cementitious mixing and pumping equipment, and an acrylate batching system. Fluorescein was used during water-pressure testing. The presentation outlines the layout, methods, equipment, and as-built profiles, but provides no final quantitative results on inflow reduction.

Keywords

grouting program

production shaft

salt mine

water inflow

timber-cribbed shaft

borehole rings

polyurethane grout

ultrafine cementitious grout

acrylate watergel

shaft dewatering