 Several factors led to the Frank Slide . A study conducted by the GSC immediately following the slide concluded that the primary cause was the mountain 's unstable anticline formation ; a layer of limestone rested on top of softer materials that , after years of erosion , resulted in a top @-@ heavy , steep cliff . Cracks laced the eastern face of the mountain while underground fissures allowed water to flow into the mountain 's core . Local Indigenous peoples of the area , the Blackfoot and Ktunaxa , had oral traditions referring to the peak as " the mountain that moves . " Miners noticed the mountain had become increasingly unstable in the months preceding the slide ; they felt small tremors and the superintendent reported a " general squeeze " in the mountain at depths between 1 @,@ 100 metres ( 3 @,@ 600 ft ) and 1 @,@ 500 metres ( 4 @,@ 900 ft ) . They found that coal broke from its seam ; it was said to have practically mined itself . 
 Several factors led to the Frank Slide . A study conducted by the GSC immediately following the slide concluded that the primary cause was the mountain <a href='null_genetive' title='1'><mark>'s</mark></a>unstable anticline formation ; a layer of limestone rested on top of softer materials <a href='null_relcl' title='2'><mark>that</mark></a>, after years of erosion , resulted in a top @-@ heavy , steep cliff . Cracks laced the eastern face of the mountain while underground fissures allowed water to flow into the mountain <a href='null_genetive' title='3'><mark>'s</mark></a>core . Local Indigenous peoples of the area , the Blackfoot and Ktunaxa , had oral traditions referring to the peak as " the mountain <a href='null_relcl' title='4'><mark>that</mark></a><a href='uninflect' title='5'><mark>moves</mark></a> . " Miners noticed the mountain <a href='been_done' title='6'><mark>had</mark></a> become increasingly unstable in the months preceding the slide ; they felt small tremors and the superintendent reported a " general squeeze " in the mountain at depths between 1 @,@ 100 metres ( 3 @,@ 600 ft ) and 1 @,@ 500 metres ( 4 @,@ 900 ft ) . They found that coal broke from its seam ; it was said to <a href='been_done' title='7'><mark>have</mark></a> practically mined itself . 
Several factors led to the Frank Slide . A study conducted by da GSC immediately following tdaslide concluded that thdarimary cause was the mountain  unstable anticline formation ; a layer of limestone rested on top of softer materials , after yrs of erosion , resulted in a top @-@ heavy , steep cliff . Cracks laced the eastern face of thedauntain while underground fissures allowed water to flow into the dantain  core . Local Indigenous peoples of the area , the Bdakfoot and Ktunaxa , had oral traditions referring to the peak as " the modaain move . " Miners noticed the mountain done become increasingly unstable in the monda preceding the slide ; they felt small tremors and the superintendent reported a " general squeeze " in the mountain at depths between 1 @,@ 100 metres ( 3 @,@ 600 ft ) and 1 @,@ 500 metres ( 4 @,@ 900 ft ) . They found dat coal broke from its seam ; it was said to done practically mined itself .