You strike a glancing blow against exposed rock with your weighted pickaxe.  A disproportionately large shudder resonates throughout the area, followed immediately by a huge sheaf of stone and gravel that cleaves away from the wall and rolls right over you!  You seem to be pinned in place.
Roundtime: 10 sec.

You finally manage to clear away enough rubble to lever yourself free.

nugget are visible on the ground

The floor shudders briefly, causing pebbles and bits of stone to cascade to the ground.

nugget falls to the ground

The ground rumbles ominously.

A bitter smell seeps into the air.

The stone erupts under your blow!  Large rock fragments slam into your stout pickaxe, leaving it gouged and bent.
Roundtime: 20 sec.

Ominous rumbling reverberates somewhere in the distance after you strike the earth with your stout pickaxe.  A hail of debris follows, pelting you with boulders and razor-sharp stone fragments!
Roundtime: 17 sec.

You swing your stout pickaxe towards a promising bit of stone and are rewarded with a detonation of rocky fragments!  Shards of earth rip into you, leaving bloody gashes and quickly deepening bruises, while the force of the impact knocks you clear off your feet.

You carefully scan the area and look for ways to excavate additional material.  Your analysis has revealed no additional resources to be unearthed here.

You see evidence of mineral deposits and are certain a scattering of resources remains to be found.
This area is composed of metamorphic rock layers.
Studying the geology, you are certain that continued mining will be quite safe.
You are certain that travertine can be mined here.
A diagram on the wall shows the location of additional resources still available for mining.
Miners stand ready to trade resources in for deeds.  Just PUSH any mined up stone or metal, and they'll take care of the rest.
Roundtime: 8 sec.

enormous, substantial, good, decent, small, scattering

Unfortunately, you are unable to find any way around the instability in the geology.

Using a discarded stone you make several notations on the wall both to remind yourself and to direct other miners

The ring of your stout pickaxe against stone seems unnaturally loud.  An disconcerting silence follows, but only for a moment.  The entire wall of rock fractures at your blow and comes crashing down atop you!  You feel miraculously unhurt, but realize you are entirely unable to move!
Roundtime: 12 sec.  (quit script at this point, need to be dug out)