"No to marginalisation," cried the mostly young demonstrators in the main square of the impoverished city of Jerada.
On Friday, two brothers died in a tunnel accident 85 metres (280 feet) below ground, sparking the fury of residents over what they view as state neglect.
"We ask the state to find solutions to our problems: unemployment, water and electricity bills that are too high," one 23-year-old protester said.
"Young people go down into the mines because they have no other option. We ask the authorities to find us an alternative," he said.
The national electricity and water board this week however said electricity bills in the Jerada region were calculated in the same way as in other parts of Morocco.
The mine was the economic lifeblood of Jerada, employing some 9,000 workers, until it was shut down in the late 1990s.
Thousands of people have since left the city and the population has fallen from 60,000 to fewer than 45,000.
But hundreds have continued to risk their lives and lung disease to find coal illegally.
On Wednesday, protesters -- many carrying Moroccan flags -- accused local officials of buying coal at very low prices from those who mine illegally to resell it at huge profit.
The demonstrators allege the officials do this despite having coal mining permits.
Minister of Energy and the Mines, Aziz Rebbah, told AFP the ministry would "withdraw any exploration or exploitation permit in the case of violation of regulations or abuse".
The authorities withdrew more than 1,400 permits nationwide in 2017, he said.
