Helical Piles In An Active Stone Mine

by | May 4, 2021 | Helical Case Study, Helical Piles

OVERVIEW:
The Gads Hill Mine in Piedmont, Missouri is owned by CertainTeed/Saint Gobain, one of the world’s largest manufacturers of building materials. This project consisted of updates to the primary crusher within the mine. As these updates took place, loads were increased. This created the need for a solution to achieve greater axial load-bearing capacity in the existing foundation.

CHALLENGE:
Challenges included extreme overhead restrictions (6’-6”) and width restrictions (8’-6”) inside an existing building where the primary crusher is housed. Other challenges were installing piers in precise locations through an existing 8” thick concrete slab while not interfering with current mining operations. The mine owner was adamant that their current operations could not be impeded by new construction.

SOLUTION:
The IDEAL Design Team provided S&B Drilling with a limited-access installation package which included a remote-controlled excavator and a compact drive head. Due to the extreme overhead restrictions, IDEAL helical pile leads and extensions were installed in 3 foot long sections. In order to not impede mine operations, the existing slab was cored and covered at each pile location. At a later date, concrete crews tied the piers into the existing foundation. Operations were not interrupted and the piers were successfully installed in a single week.

 

INSTALLER:
S&B Drilling

LOADS:
Compression design load: 22.5 kips
Tension design load: 60 kips
Lateral load: 4.5 kips

PILE DETAIL:
4.5” O.D. X 0.290″ W.T. – 80 ksi central shaft

SOILS + EMBEDMENT DEPTH:
The soils in this area are predominantly residual deposits, resulting from weathering of parent bedrock. Subsoils encountered in borings consist of a reddish-brown mottled gray silty clay with chert gravel. The silty clay extends down to at least 50 feet below the existing ground line.

NUMBER OF PILES:
41

EMBEDMENT DEPTH:
24’

VIEW SOILS REPORT