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PROCEDURES Pipelines Five 250-ft-long sections of transmission pipeline, with properties described in table 1, were installed on the AP1AX Coal Company's t•linnehalra Kline highwall for testing to destruction. They were all parallel to each other with l0-ft spacings and also to the highwall at an initial distance of about 500 ft as shown in figure 1. The location, in increasing distance from the highwall, are as listed in table 1. Ohio Valley Pipeline welded and installed the pipelines, using their standard procedures, after the Bureau attached longitudinal and circumferential strain gages and sensors for vibrations in the center area of the pipelines. All pipelines had longitudinal strain gages on tops and fronts and the 6- and 20-in lead circumferential as well. Vibration transducers were also placed on tops and fronts of the 6- and 20-in pipes. Other vibration sensors were placed on the surface above the buried 20-in pipeline. Following installations and the placement of 3-ft of soil cover, tl+e pipelines were internally pressurized (Figs. 2-3). Pressures gradually crept up in steel pipelines to 950-1230 lb/inz as the ground warmed up from early spring to summer. It dropped in the PVC to 40 lb/inZ in the following months consistent with reports that such o-riny-jointed water pipes leak continuously. Note: Figure 1 does not slow blasts 26 ihr•ough 30, done too late to be included. Mine The hlinnehaha Cline is a surface coal mine, blasting overburden by casting and also a thick parting using hole diameters of 12-1/4 and 10-5/8-in, respectively. Charge weiylrts per delay are as Iriglr as 2,100 lbs. The highwall, including the pipeline field area, has about 7 ft of clayey soil over-lying about 40 ft of shale. Monitoring Strains and ground and pipeline vibrations measured by the authors from selected parting blasts and all nearly overburden blasts are presented in table 2. In addition, Vibronics ]nc. continuously monitored both surface and underground vibrations at several locations as v+ell as pipeline pressures. At•1AX and the ]DIJR also had blasting monitors in the area for purposes unrelated to the pipeline study. In front of the pipeline, At•1AX had installed both coaxial and fiber-optic phone cables, and also had a vertical well off ttre east end of the 6-in pipeline. The well, of about 120-ft depth, was instrumented for pressure by Vibronics. It was tested for- cement bond lag on three occasions: prior- to blasting, after 4 in/s and after 9 in/s. No siynificant bond loss was noted. The phone lines were tested by ]ndiana Bell and will be reported separately. 132