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• Base Camp and Halligan Mesa - Lazygranch.com
• CIA "Plan Columbia" aircraft at Base Camp - Lazygranch.com
• CIA Paratrooper Exercise at Base Camp - Lazygranch.com

Mysterious Civilian C-130 (L-328G) at Base Camp - Lazygranch.com

Roller Coaster was a joint US (DOD)-UK test program to collect data on the safety of weapons due to accidental detonation. unlike most other weapon safety tests, this was not concerned with the question of one-point safety and the possibility of nuclear yields. The warheads used in these tests were known to be one-point safe. Instead the concern was the hazard presented by the dispersal of plutonium if the explosives were accidentally detonated (as happened in the 1966 hydrogen bomb accident at Palomares Spain).

These tests are arguably the last U.S. atmospheric tests. Although they produced no nuclear reactions, and were not expected to, the U.S. government counts them in the official list of nuclear tests.

OCR - Double Tracks

Summary: This test was part of Operation Roller Coaster. Four storage and transportation tests on the NAFR were conducted as Operation Roller Coaster during May and June 1963.

DOUBLE TRACKS was a non-nuclear experiment that took place on Stonewall Flats at 0255 hours on May 15, 1963. The purpose of this test was to determine data on debris scattering. To accomplish this purpose, conventional high explosives were used to scatter an alpha-emitting isotope into the atmosphere.

Filters from air samplers taken at populated locations indicated a maximum concentration of 12.1 disintegration per minute/cubic meter at Scotty’s Junction, Nevada. (The air sample with this highest reading was from an air sampler with a burned out motor, and the total air flow had to be estimated.) A filter from a sampler run from 1245 hours May 14 to 1300 hours on May 15 in Beatty, Nevada, showed 11.3 disintegrations per minute per cubic meter. Other filters from populated locations showed concentrations above the 0.04 disintegrations per minute per cubic meter background level.

Test: DOUBLE TRACKS
Date: 05/15/63 Sponsor: Joint US-UK
Time: 0255 PDT Depth of Burial: Not Applicable
Location: NAFR Purpose: Storage-Transportation
Type: Surface Yield: Zero
Release Type of
Detected: Offsite Release: Test/Plutonium Dispersal
Test Release at R+12 Hours, in Curies: Unknown
Maximum Activity Detected in Air Offsite: Estimated 12.1 disintegrations per minute per
cubic meter (alpha) at Scotty’s Junction, Nevada
Maximum Gamma Exposure Rate Detected Offsite: No offsite gamma radiation was
detected.
Maximum Iodine Level Detected Offsite: Non-nuclear experiment, no iodine was produced.
Maximum Distance Radiation Detected Offsite: Alpha activity detected on air samplers at
Beatty, Nevada and Scotty’s Junction, Nevada

Summary: The test was part of Operation Roller Coaster. Four storage and transportation tests on the NAFR were conducted as Operation Roller Coaster during May and June 1963.

At 0417 hours on May 25, 1963, CLEAN SLATE I, a conventional high explosive device with a plutonium-239 component, was detonated at Cactus Flats, Nevada. The purpose of this experiment was to determine data on the extent and concentration of alpha-emitting debris scattering from a conventional high-explosive device equipped with one or more alpha-emitting components.

Due to fluctuating wind patterns, air filters from populated areas northeast and southeast of surface ground zero showed small concentrations of alpha-emitting material with a maximum activity of 0.32 disintegrations per minute per cubic meter of air at Lathrop Wells, Nevada. Filters from populated areas (including Hiko, Lund, Mesquite, Pioche, Tonopah, Warm Springs, Las Vegas, Furnace Creek, and Lathrop Wells) showed small concentrations of contaminated material.

Test: CLEAN SLATE I
Date: 05/25/63 Sponsor: Joint US-UK
Time: 0417 PDT Depth of Burial: Not Applicable
Location: NAFR Purpose: Storage-Transportation
Type: Surface Yield: Zero
Release Type of
Detected: Offsite Release: Test/Plutonium Dispersal
Test Release at R+12 Hours, in Curies: Unknown
Maximum Activity Detected in Air Offsite: 0.32 disintegrations per minute per cubic meter
(alpha) at Lathrop Wells, Nevada
Maximum Gamma Exposure Rate Detected Offsite: No offsite gamma radiation was
detected.
Maximum Iodine Level Detected Offsite: Non-nuclear experiment, no iodine was produced.

ORC - Clean Slate 2

Summary: This test was part of Operation Roller Coaster. Four storage and transportation tests on the NAFR were conducted as Operation Roller Coaster during May and June 1963.

CLEAN SLATE II, the third non-nuclear experiment of Operation Roller Coaster, was carried out on Cactus Flats, Nevada, at 0347 hours, May 31, 1963. The purpose of this detonation was to determine data on the extent and concentration of debris scattering from a conventional high-explosive device equipped with one or more alpha-emitting isotope components. Air filter results from 31 permanent stations surrounding the test area indicated that any material released from CLEAN SLATE II was confined to the Cactus Flats location.

Test: CLEAN SLATE II
Date: 05/31/63 Sponsor: Joint US-UK
Time: 0347 PDT Depth of Burial: Not Applicable
Location: NAFR Purpose: Storage-Transportation
Type: Surface Yield: Zero
Release Type of
Detected: Onsite Only Release: Test/Plutonium Dispersal
Test Release at R+12 Hours, in Curies: Unknown

ORC - Clean Slate 3

Summary: This test was part of Operation Roller Coaster. Four storage and transportation tests on the NAFR were conducted as Operation Roller Coaster during May and June 1963.

At 0330 hours on June 9, 1963, the CLEAN SLATE III test was conducted at Cactus Flats, Nevada. The purpose of this test was to determine data on the extent and concentration of alpha-emitting debris scattering from a conventional high-explosive device with one or more radioactive components. This was the fourth and last test of the Roller Coaster series. Careful ground monitoring to the southeast and southwest of surface ground zero failed to show any readings above background levels. The area was monitored after heavy morning and afternoon rains on June 9, 1963.

Test: CLEAN SLATE III
Date: 06/09/63 Sponsor: Joint US-UK
Time: 0330 PDT Depth of Burial: Not Applicable
Location: NAFR Purpose: Storage-Transportation
Type: Surface Yield: Zero
Release Type of Detected: Offsite Release: Test/Plutonium Dispersal
Test Release at R+12 Hours, in Curies: Unknown
Maximum Activity Detected in Air Offsite: Not above background; a maximum of
1.64 x 10 -13 microcuries per cubic centimeter was measured on the Test Range Complex.
Maximum Gamma Exposure Rate Detected Offsite: No offsite gamma radiation was
detected.
Maximum Iodine Level Detected Offsite: Non-nuclear experiment, no iodine was produced.
Maximum Distance Radiation Detected Offsite: 47.8 + 1.5 disintegrations per minute per
square foot of 239, 240 Pu on a film collector at Springdale, Utah

Posted by dracolich

Date of construction is completely unknown. The 1st time it was even charted was in 1987, but it appears to be much older than this. A more believable option is that it was constructed during WW-II as an emergency strip for AAC training in this remote area, and just was never charted because of it's location in a restricted area.

Built about 1943 and abandoned about 1959. It was then reopened in the 1980's, as Mellan, to support training by the DOE & USAF in the surrounding areas..