What happens in the poem "The Explosion"?

Philip Larkin wrote ‘The Explosion' after viewing an 1969 BBC documentary about coal mining. The specific event described may well have been the disaster at the Trimdon coal mine, near Durham in northern England on 15 February 1882 in which 74 people died, although many aspects of the poem are relevant to any coal mine explosion. 
The poem starts out on a ordinary day in which miners are headed into the mine. Above ground, the scene is pleasant and pastoral. One miner steals eggs from a lark's nest for food. They head into the mine. At noon, there is an explosion, kicking up dust that dims the sun. 
After the explosion, the speaker and the wives of the miners who died, shift to a religious viewpoint, momentarily lifted out of the mundanity of daily life by the enormity of the event.