"Tar sand, in the most genera! sense, can be described as a heavy bituminous oil locked into the interstices of a rock or sand matrix. The material has a variable degree of consistency ranging from dense rock to unconsolidated sand. Much of tar sand has the consistency of asphalt, in fact, tar sand is sometimes referred to as natural asphalt. The bitumen, locked into its matrix, is a very heavy, complex material composed primarily of hydrocarbons. Tar sand is located in many areas of the world. Some of the largest deposits are located in Venezuela and Canada. The bitumen from tar sands, especially in Alberta, Canada, is currently being recovered by strip mining techniques. The United States has an estimated 30 billion barrels of oil in the form of tar sand [1]. This is very significant since we now have about 26.5 bill ion barrels in the national oil reserve [2]. The tar sand deposits are located in several states such as Kentucky, California, New Mexico, and Texas, however, over 95 percent is located in Utah [I]. There are two primary reasons that the tar sands in the United States cannot be recovered by strip mining, as it is recovered in the Athabascan sands in Alberta, Canada. First, most of the sands in the U.S. are beneath an overburden of up to several hundred feet. The Athabascan sands are very near the surface. The second primary difference is the structure of the tar sand itself. The Athabascan sands have a film of water separating the bitumen and the sand [3]. This property allows the tar sands to take an unconsolidated form. The tar sands in the U.S. are typically drier tending to make the bitumen physically attach itself to the sand [1]. Since strip mining tar sand in the U.S. is both economically and ecologically less feasible, other recovery techniques must be investigated. One of the possible extraction techniques being studied is termed in situ recovery. In situ recovery is any method by which bitumen is removed while the deposits are still in place. There are several methods presently being considered, a few of which will be discussed below."