Page 41 - 2019 Sustainability Report

By the time a tire has passed through the entire shredding
system, the rubber — now resembling very fine chips — Tire chips produced by the shredding
is moved off to the kiln for use in the cement-making system are moved to Midlothian’s kiln
process. The metal is collected in a large bin and later by a large conveyor.
sold for scrap.

The system can handle tires of any size — from large
ones like those used on tractor-trailers to the small ones
you might find on a standard lawnmower.
While the system works smoothly now, Del Valle Favela
said its adoption was not without its challenges.
“There’s nothing like this anywhere else, so there were
growing pains,” he said. “We had to fine-tune it. We had
to figure out how to make it grab one tire at a time at just
the right rate. The grinders generate heat, so we had to
figure out how to prevent fires.”

“It’s helping us control costs while
driving profits. Overall, it’s been
a spectacular investment.”

With a bit of experimentation, the team was able
to conquer the shredding system’s most significant
challenges. Midlothian then added four new employees,
creating a team of nine to run the system nonstop. Now,
the plant has an environmentally friendly fuel source that
helps maintain high operating standards and efficiencies.
“It’s helping us control costs while driving profits,”
Del Valle Favela said. “Overall, it’s been a spectacular
investment.”

Discarded tires move along a conveyor en route to becoming an
alternative fuel source at the Midlothian Cement Plant in Texas.

41 / MARTIN MARIETTA / SUSTAINABILITY REPORT / 2019