Page 27 - 2019 Sustainability Report

Accordingly, although our actual carbon emissions from • In the last five years, we have dramatically reduced
clinker production may be comparable to or better than the use of coal in our kiln fuel mixes at both cement
European producers, their ability to calculate reportable plants from approximately 70 percent to 23 percent
CO emissions differently leads, in part, to a lower carbon of our total fuel usage. In particular, at Midlothian,
2
intensity calculation. coal makes up less than 9 percent of the kiln’s fuel, as
compared to 59 percent in the past. At Hunter, the
Simply put, because U.S. producers are more heavily percentage of coal in the fuel mix is 41 percent, down
regulated in using alternative fuels in production and must from 77 percent, and we are actively exploring ways to
both report a greater amount of the related CO emissions obtain additional supplies of natural gas at Hunter as
2
than their European competitors and use more higher- an alternative to coal use.
CO clinker in cement, carbon intensities are effectively
2
calculated differently for U.S. and European producers.
OUR MAGNESIA SPECIALTIES BUSINESS
Despite these regulatory constraints, Martin Marietta
views the use of alternate fuels and improving After our cement business, our magnesia specialties
fuel efficiency as important components of our business, which has two plants — one in Ohio and one
overall commitment to sustainability, including in Michigan — is the second largest contributor to our
climate change-related issues and concerns. In this Scope 1 GHG footprint. This is due almost entirely to the
regard, in addition to significant plant upgrades and operation of our Woodville, Ohio, plant where we operate
other modernization in which we have invested, our six lime kilns of varying ages. The calcination process at
accomplishments include the following: Woodville is very similar to our cement business, except
that Woodville processes dolomitic limestone, which
• As noted later in this Sustainability Report, we have contains a higher CO component than the high calcium
2
made a significant investment in tire processing limestone used in our cement plants. In contrast to
systems at our Midlothian Cement Plant and are cement, our magnesia specialties business cannot achieve
actively exploring adding such equipment to our GHG reductions through substitution for our calcined
Hunter Cement Plant in the next several years. Our lime product since both internal and external customers
permits for our Midlothian and Hunter plants, however, require that we maintain extremely high purity to allow
cap our use of tires as alternate fuels to, respectively, further processing.
28 percent and 25 percent of the fuel mix.

Members of the U.S. Air Force visit the
Midlothian Cement Plant in Texas to observe
the Tire Derived Fuel system.

27 / MARTIN MARIETTA / SUSTAINABILITY REPORT / 2019