years. Although growth in consumption could reduce this ratio in the future, particularly if few new supplies are added to the resource base, the resource base could expand if the very large potential is realized.

In addition, the Riley Ridge area of Wyoming is estimated to contain a nondepleting resource of helium of approximately 47 billion scf (1.3 billion scm) (Gage and Driskill, 1998). This helium is contained in low-quality natural gas that is not currently economic to produce. Should it become so, perhaps as a result of increased helium prices, it would increase the current reserves/production ratio by over 13 years.

Similar observations could be made with regard to worldwide helium supplies. Liquefied natural gas is becoming an important component in the world's energy supplies. Because methane liquefaction concentrates the remaining gas stream, there are potentially other sources of helium throughout the world, even in low-helium-concentration gases (such as those found in Algeria).