Heavy infrastructure services in the nature of construction of roads, commercial buildings, power plants, pipelines, tunnels, bridges, airports, rail lines, transit lines, marine structures, power generating structures and power transmitting structures, but not related in any way to real estate leasing services, property management services, real estate development services, sand and gravel mining other than related to Flatiron West's use and delivery of sand and gravel in it's own construction projects but not as a service marketed to third parties, or sale and delivery of sand and gravel for use by others other than related to Flatiron West's use and delivery of sand and gravel in it's own construction projects but not as a service marketed to third parties