Ground Truth Collection for Mining Explosions in Northern Fennoscandia and Northwestern Russia

• Main Authors: Harris, D B, Ringdal, R, Kremenetskaya, E, Mykkeltveit, S, Rock, D W, Maercklin, N, Schweitzer, J, Hauk, T F, Lewis, J P
• Language: unknown
• Published: 2021
• Subjects: 01 COAL; LIGNITE; AND PEAT; 58 GEOSCIENCES; EXPLOSIONS; FRACTURES; GROUND TRUTH MEASUREMENTS; MINING; POTENTIAL ENERGY; SHEAR; SURFACE EXPLOSIONS; SURFACE MINING; UNDERGROUND EXPLOSIONS; WAVE FORMS; Kiruna; Khibiny; Kovdor; Olenegorsk; Fennoscandia; Malmberget; Northern Sweden
• Online Access: http://www.osti.gov/servlets/purl/878633; https://www.osti.gov/biblio/878633

We concluded comprehensive ground truth collection at the Khibiny, Olenegorsk, Kovdor, and Zapolyarnyi mines, and have basic information on 2,052 explosions. In the past two years we used this ground truth information to extract waveform data from the ARCES array and a number of regional stations (KEV, LVZ, APA) as well as from six stations that we deployed along two lines stretching between the Khibiny Massif mines and the region around the ARCES array. We calculated P/S ratios using the ARCES array data for many of these events comprising several source types (compact underground explosions, underground ripple-fired explosions, surface ripple-fired explosions). We found that the P/S ratios of small compact underground explosions in mines of the Khibiny Massif are systematically lower than the P/S ratios of large ripple-fired surface explosions. We had anticipated that smaller underground shots would appear more like single well-coupled explosions, thus having higher P/S ratios than large ripple-fired explosions. A possible explanation for this phenomenon is that the compact underground explosions in these mines are designed to fracture and drop a large quantity of ore from the ceiling of a horizontal shaft. The potential energy released by the falling ore may express as shear wave energy, which may be considerably greater than the (P wave) energy released directly by the explosive. We concluded the deployment of the six stations along the Khibiny-ARCES lines this past summer; this year we are examining the data from these stations to see how P/S ratios vary with range from the source. We have an update on the P/S ratio analysis contrasting different source types, with the addition of an analysis of range dependence using data from the temporary stations. The portable stations were redeployed in the fall of 2004 to the Kiruna and Malmberget underground mines in northern Sweden. The stations deployed in Malmberget also record events from the surface mining operations at the Aitik mine, located some 15 km from ...