Page 77 - 2023 Sustainability Report

ENVIRONMENTAL STEWARDSHIP

significantly reduced the volume of water appropriated for gravel washing. The addition of the plate press also allowed us
to recover additional water while converting “pond fines” (small rock particles suspended in water) into a co-product
generated from the process.

The automated truck wash systems installed at our DFW
ready mixed concrete operations are very effective at
reducing the water used to wash trucks prior to leaving the
site, along with speeding up the process. A prior study on
water use identified that the manual rinsing of each truck,
per load, resulted in an average duration of 5 minutes, and
around 150 gallons of water. The automated truck was
systems reduced this duration to about 90 seconds, and
only 40 – 60 gallons of water per truck, per load. Since
that time, Martin Marietta has refined the programming of
the system, further reducing the time to wash to 35
seconds, and only using 20 – 30 gallons per truck, per
load. With these systems at 25 of the 28 DFW ready mixed
concrete facilities, the water savings are substantial. For
instance, last year, the DFW Ready Mixed District produced
approximately 2.4 million cubic yards from facilities
equipped with automated truck wash systems. This volume
of concrete equates to almost 261,000 truck trips,
resulting in an estimated water reduction of more than 31
million gallons for the year. In addition, the approximately
4 minute reduction of idling time per truck while onsite has
a direct impact on diesel emissions.

The West Division continues to work in cooperation with
the City of Denver, the City of Aurora and the State of
Colorado to create much-needed new fresh water
reservoirs at our facilities. These water projects include on-
going projects at our Riverbend Sand & Gravel, 35th
Avenue, Taft Sand & Gravel, Specification Aggregates,
Duckworth, and Heaton facilities with the opportunity to
repurpose more pits in the future. The West Division is also An automated truck wash in our DFW operations
working to develop storage facilities in other locations
within its footprint to serve various communities.

Our Colorado Front Range operations are situated adjacent to rivers, streams and ditches that provide vital water for
agricultural, residential and commercial purposes. This system of water distribution through streams and ditches was
established in the 1880’s supplying water from the Mountains to the Front Range below. Through our numerous water
rights, four state approved reservoirs and leases, Martin Marietta operates to ensure there is no net water loss to the
stream system. This means that our total water usage is returned back monthly to the stream system and the surrounding
aquifers. In 2023, Martin Marietta returned over 400 million gallons of water back to the environment through this
process.

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