Northern Stillness

[heslopian]

Well north of the bustling city
before the crackle of nights winter fires Should "fires" have a comma after it? Also, this and the following line might be clearer if you put "winter fires" beside "hard hats".
hard hats, black backs and frozen fingers
shiver smoothly in time with their iron picks To improve the syntax here I'd suggest putting a comma after "iron picks" and changing the next line to "striking sharply upon the icy earth".
sharp strikes upon the icy earth,
shattering the frozen northern stillness.

This poem is quietly beautiful in its portrait of a city in winter. It's like a tiny painting which captures the contrast between human industry and nature. All critique is JMHO; thank you for the read