  We propose to utilize bedrock as a medium for acoustic detection of particle
showers following interactions of ultra-high energy neutrinos. With the density
of rock three-times larger and the speed of sound four-times larger compared to
water, the amplitude of the generated bipolar pressure pulse in rock should be
larger by an order of magnitude. Our preliminary simulations confirm that
prediction. Higher density of rock also guarantees higher interaction rate for
neutrinos. A noticeably longer attenuation length in rock reduces signal
dissipation. The Pyh\"asalmi mine has a unique infrastructure and rock
conditions to test this idea and, if successful, extend it to a full-size
experiment.
