Specifications include, but are not limited to: . The Contractor shall: a. produce a sufficient quantity of materials meeting the specifications to complete the project; b. as a subsidiary cost: clear and grub, strip, drill and blast, excavate, crush, sort, blend, screen, wash, stockpile, haul, and rehandle material as needed to produce and deliver the specified product; c. determine the type of equipment and methods to be used; d. expect variations in material quality within the deposits, and procure material only from acceptable portions of the deposit, regardless of source ownership; and e. prevent erosion, sedimentation, and pollution within a materials source. The Contractor agrees that: a. the costs to explore and develop material sources, including all production effort, are subsidiary to the cost of providing the specified material; b. the Engineer may order the Contractor to procure material only from certain portions of the source and may reject material from other portions of the source that does not conform to the specifications; and c. all material required may not be procurable from any one source and the Contractor may need to change between sources. That contingency is to be factored into the unit bid price for the Contract Item.