Polar plots of surface wind fields near the mine and the two arrays during the times when acoustic signals were generated (at mine) and were observed or expected to be observed (at arrays). The plots in the left-hand side column are for time periods in which the ‘blasts were not detected’ and the right-hand side column represents time periods when ‘blasts were detected’ at each array. (a and b) Wind fields around the mine with respect to signal detection at CHNAR, and (c and d) at ULDAR. (e and f) Winds fields around CHNAR with respect to signal detection at the array. (g and h) same plot for ULDAR. The size of the circles are proportional to the maximum acoustic pressure recorded at the in-mine stations. Thick lines indicate preferable wind directions to each array.