US5388642-A  "Kirk-Othmer Encyclopedia of Chemical Technology" 3rd Ed., Volume 15, pages 92-131 (1981);  John L. Gidley, et al., Recent Advances in Hydraulic Fracturing, Volume 12, Society of Petroleum Engineers Monograph Series, 1989, pp. 25-29 and pp. 76-77;  SPE 22893, "Injection Above-Fracture-Parting Pressure Pilot, Valhal Field, Norwey," by N. Ali et al., 69th Annual Technical Conference and Exhibition of the Society of Petroleum Engineers, Dallas, Texas, 06101991-09101991;  Schuster, C. L., "Detection Within the Wellbore of Seismic Signals Created by Hydraulic Fracturing", paper SPE 7448 presented at the 1978 Society of Petroleum Engineers' Annual Technical Conference and Exhibition, Houston, Tex., October 1-3;  "Kirk-Othmer Encyclopedia of Chemical Technology", 3rd Ed., vol. 15, pp. 92-131, (1981);  "Quaterly Review of Methane from CoalSeams Technology", Gas Research Institute, vol. 11, No. 1, p. 38, (1993);  09111990, Report of the Oil and Gas Conservation Commission of the State of Colorado;  Alan A. Reznik, Pramod K. Singh and William L. Foley, "An Analysis of the Effect of Carbon Dioxide Injection on the Recovery of In-Situ Methane from Bituminous Coal: An Experimental Simulation", SPEDOE 10822, (1982);  Amoco Production Company Handout distributed at the International Coalbed Methane Symposium held in Birmingham, Ala., 17051993-21051993;  Application for Enhanced Recovery Nitrogen Injection Pilot and Approval of Aquifer Exemption, submitted to the Colorado Oil and Gas Conservation Commission, 30081990;  Brian Evison and R. E. Gilchrist, "New Developments in Nitrogen in the Oil Industry", SPE 24313, (1992);  Carl L. Schuster, "Detection Within the Wellbore of Seismic Signals Created by Hydraulic Fracturing", SPE 7448, (1978);  Durango Herald Newspaper Article, "Planners OK Amoco Facilities", dated 15051991;  Jacob E. Koresh and Abrah Soffer, "The Carbon Molecular Sieve Membranes, General Properties and the Permeability of CH4H2 Mixture", Separation Science and Technology, vol. 22, nos. 2&3, pp. 973-983, (1987);  Jacob E. Koresh and Abraham Sofer, "Molecular Sieve Carbon Permselective Membrane. Part 1. Presentation of a New Device for Gas Mixture Separation", Separation Science and Technology, vol. 18, No. 8, pp. 723-724, (1983);  La Plata County Planning Commission, Colorado Planning Commission Information Session of Mar. 1991 dealing with Amoco's Planned Nitrogen Injection Pilot;  M. D. Stevenson, W. V. Pinczewski and R. A. Downey, "Economic Evaluation of Nitrogen Injection for Coalseam Gas Recovery", SPE 26199, (1993);  M. G. Zabetikis, et al., "Methane Control in United States Coal Mines-1972", U. S. Bureau of Mines, Information Circular 8600, pp. 8-16, (1973);  N. Ali, P. K. Singh, C. P. Peng, G. S. Shiralkar, Z. Moschovidis and W. L. Baack, "Injection Above-Parting-Pressure Waterflood Pilot, Valhall Field, Norway", SPE 22893, (1991);  N. R. Warpinski and Michael Berry Smith, "Rock Mechanics and Fracture Geometry", Recent Advances in Hydraulic Fracturing, vol. 12, chapter 3, pp. 57-80, S.P.E. Monograph Series, (1989);  Nigel McMullen and Miro Hojsaki, "Reconsider Noncryogenic Systems for On-Site Nitrogen Generation", Chemical Engineering Progress, pp. 58-61, (1993);  R. Puri and D. Yee, "Enhanced Coalbed Methane Recovery", SPE 20732, (1990);  R. S. Metcalfe, D. Yee, J. P. Seidle, and R. Puri, "Review of Research Efforts in Coalbed Methane Recovery", SPE 23025, (1991);  Ralph W. Veatch, Jr., Zissis A. Mosachovidis and C. Robert Fast, "An Overview of Hydraulic Fracturing", Recent Advances in Hydraulic Fracturing, vol. 12, chapter 1, pp. 1-38, S.P.E. Monograph Series, (1989);  United States Environmental Protection Agency Region VIII, Transmittal Letter of 11021992 approving Nitrogen Injection Pilot and Associated PermitsWO9512745-A1  OIL & GAS JOURNAL, vol.89, no.43, 28/10/1991, TULSA, OKLA., USA page 30 AMOCO "Amoco plans test of nitrogen injection for coalbed methane";  OIL & GAS JOURNAL, vol.89, no.43, 28 October 1991, TULSA, OKLA., USA page 30 AMOCO 'Amoco plans test of nitrogen injection for coalbed methane'