Abstract: This invention relates to a method of reinforcing tunnels which comprises driving a crown drift along the top of the proposed tunnel, driving a pair of wall plate drifts along opposite sides of the proposed tunnel in spaced substantially parallel relation beneath and to one side of the crown drift, drilling a longitudinally spaced aligned or staggered series of small diameter bores downwardly and outwardly in both directions from within the crown drift along the ceiling of the proposed tunnel, drilling other series of similar bores upwardly from within the wall plate drifts along the walls of the proposed tunnel, said ceiling and wall bordering bore patterns being inclined toward one another and of a length such as to produce a skewed overlapped relation, inserting reinforcing rods into the bores of each series thereof so as to produce a metal curtain between drifts bordering the perimeter of the proposed tunnel, grouting the rods permanently in place within their respective bores, filling the drifts back up