Following the closure of the No. 4 Shaft, a grocer named Anthony Giachino purchased
the building and constructed Giachino’s Grocery, enclosing the headframe with the
store building in 1926 (Brown, 1999). Figure 1 shows the building in what is estimated
to be the 1940’s. Giachino used the No. 4 Shaft and the cold air from the mine as a
cold storage for produce and meats. Several businesses have since occupied the
building including multiple restaurants (Figure 2 and Figure 3), and it is currently in use
as a residential apartment and a publisher (Figure 4).
Experience on this rehabilitation has shown that cemented backfilling of mine openings
to surface using a remotely constructed foam barricade is appropriate when
infrastructure is present above the mine opening, or minimal disturbance of the
surface/infrastructure is desired. The cost is comparable to constructing a monolithic
cap above the mine opening, and concrete backfill should be considered as an
alternative where possible. Application of the initial foam barricade is the greatest
challenge, and the Coniagas No. 4 Shaft had favorable conditions of a vertical void with
an obstruction at a reasonably shallow depth. Alternative methods of constructing a
temporary barricade to build the foam plug, or incrementally building the foam plug from
off of the rock walls, may be necessary depending on site and void geometry.