Date: December 14, 2007
Location: Chevron Mine Draw Points, Questa New Mexico
Contractor: Smith’s Waterproofing, Almont MI
Engineer: Kevin Sparks P.E., Chevron Mining Corporation
Material Used: Fortec Carbon Kevlar Grid
Most mines have various levels. The top level is usually where blasting occurs, and the level(s) below act as a funnel to extract mining material. A Draw Point is an entry point to retrieve material. These Draw Points are poured in place with a small tolerance to fit bucket machinery and are usually in a classic arch design.
Each Draw Point is affected by 40 lb blasts of TNT once a day. Steel reinforcement would add to the problem of removing sheared draw point material. Smith’s Waterproofing reinforced 2 Draw Points with Carbon Kevlar Grid for testing. Carbon Kevlar Grid was surface mounted on one Draw Point in a 2 ft on center checker grid pattern, while on the second it was installed in 1 ft on center pattern.
The closer pattern survived days of blasting before showing signs of damage, while the 2 ft pattern began to shear on the first blast. Also surface mounting needs to be protected from scrapping of the bucket machinery. However, Carbon Fiber has a big future in Mining Draw Points. We are now in the process of designing a product to meet these specific needs.