Rio Tinto Borates
The Boron Open Pit is the largest operating open pit mine in California. The mine produces a third of the world’s supply of refined borate products (1 million tons). The mine has a footprint of 1.74 miles wide, 1.99 miles long, and 755 ft deep. The pit walls consist of weak and unconsolidated clay-like sedimentary strata, including both waste rock and ore with occasional perched aquifers.
Agapito Associates Inc. (AAI) has provided consulting engineering services to U.S. Borax (now Rio Tinto Borates) since 2013. AAI’s contributions to the safe development and ongoing operation of the Boron Mine include:
- Developing global slope Factors of Safety (FoS) for highwalls in two separate pits
- Assessing long-term stability of pit highwalls incorporating solution mining cavities
- Studying the effect of solution-filled cavities on highwall stability
- Identifying safe pressure levels in solution cavities from a highwall stability perspective
- Recommending buffers between the highwall slope and solution mining cavities
- Underground mine planning and design beyond pit limits
- Solution mine planning and design
