U.S. Geological Survey, Acquisition & Federal Assistance, Building 25, Box 25046, MS 204B, Denver Federal Center, Denver, CO 80225

B -- HELICOPTER ELECTROMAGNETIC SURVEY DUE 073196 POC Deborah Boles, Contracting Officer, (303) 236-5900 x316 Concerns having the ability to furnish the services described herein are requested to givewritten notification (including the telephone number for a point of contact) to the procuringoffice above within forty-five (45) calendar days from the date of this synopsis. Therequirement is for an airborne electromagnetic survey covering approximately 400 squaremiles with a line spacing of 1/4 mile for a total survey size of about 1600 line-miles ofportions of Everglades National Park and surrounding lands. The time frame for flying thissurvey is June-August 1996. The intent of this survey is to provide data necessary to monitorchanges in the hydrologic system by comparison of these results with previous helicopterelectromagnetic (HEM) surveys of the area. It is critical that the results of this survey can bedirectly compared with those of previous surveys. Therefore, the HEM system used for thissurvey must duplicate the instrumentation previously used which had the followingcharacteristics: 1) electromagnetic sensor operating at five frequencies and a multi-coilgeometry, namely three horizontal coplanar coil pairs operating at frequencies of 59780 Hz,7255 Hz, and 1054 Hz and coil spacings of 6.3 m, 8.0 m, and 8.0 m respectively, and twovertical coaxial coil pairs operating at frequencies of 5790 Hz and 871 Hz, and coil spacingsof 8.0 m and 8.0 m respectively; 2) each electromagnetic channel is capable of measuring theinphase (I) and quadrature (Q) response with noise levels over a 0.2 second averaging time ofnot more than 3.0 ppm for lowest two frequencies, 5.0 ppm for the two intermediatefrequencies, and 10.0 ppm for the highest frequency and drift rates of not more than 20ppm/hr for the lowest two frequencies, 40 ppm/hr for the intermediate frequencies, and 60ppm/hr for the highest frequency; 3) the ten electromagnetic channels as well as two sfericand two power line noise monitoring channels will be measured every 0.1 s; 4) the systemshall be calibratable with an external coil, as well as an internal coil which is operable duringsurveying; 5) a dipole transmitter moment of at least 900 ampere-turns-meter-squared at thelowest frequency (900 Hz) and 6) real-time differential GPS navigation to insure the reflightof lines measured during previous surveys of the area. In addition data processing procedurescompatible with previous surveys are also required. Key data processing characteristicsinclude: 1) digital processing of data to remove noise due to sferics; 2) filtering to removeany system noise; 3) leveling adjustment of data so as to produce high quality resistivity mapproducts; 4) apparent resistivity and apparent depth calculations from the inphase andquadrature data from the five coil pairs using a pseudo-layer, half-space model; and 5)calculation of Sengpiel and differential resistivity sections along flight line paths. Based oninformation available at this time, and in accordance with 41 U.S.C. 253(c)(1), implementedby FAR 6.302-1, the Government considers the item specified as a sole source from Digem I-Power, Mississauga, Ontario, Canada and proposes to negotiate a contract with that firm onthat basis. However, should additional sources be identified, they will be considered. Firmswho feel that they can furnish the required item or its functional equivalent (based upon thecriteria specified herein) are invited to submit in writing an affirmative response to thisannouncement. An affirmative response would include literature, brochures and such othermaterials which correspond to the required items stated herein. This information will beevaluated and used to determine if competitive opportunities exist. Since no solicitationdocument exists, requests for such documents without accompanying information will beconsidered non-responsive to this request without further consideration. This notice mayrepresent the Government's only official notice of this procurement. See Note 22(0143)

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