Abstract: Tar sand and Gilsonite are preferably crushed together so that the Gilsonite overcomes the stickiness of the tar sand and the tar sand alleviates Gilsonite dust, the relative proportions and the character of Gilsonite being such as to produce an additive product for an asphalt, usually refinery asphalt, and a resulting modified asphaltic cement for paving purposes to simulate Trinidad Lake Asphalt. One embodiment of the additive composition of the invention results in an asphaltic cement that outperforms that produced by use of Trinidad Lake Asphalt as the additive, while a second embodiment of the additive composition of the invention contains additional tar-sand-extracted bitumen and the resulting asphaltic cement more closely matches the performance of that containing Trinidad Lake Asphalt as the additive. The invention includes a system for extracting bitumen from tar sand and in one form provides for adding Gilsonite to the extracted liquid bitumen so it will effectively solidify when cooled.