The theme of class conflict pervades the entire novel. The miners and the mine owners are perennial class antagonists, with the working-class miners strongly contrasted to the owners. The long-simmering conflict has rarely come to a boil, however, so the owners have allowed themselves to believe that they have a positive relationship with the workers.
Émile Zola portrays specific characters as individuals and within their families to give intimate portraits of this antagonism and its effect on specific people. The mine-owning family, the Grégoires, has become detached from awareness of other people’s labor, which makes their comfortable, lavish lifestyle possible. The family and others like it try to maintain a closed society, in which their offspring marry those of a similar family; this is the case with Cécile Grégoire’s engagement.
The labor organizers who challenge the mine-owning families have banded together with various ideas of how to improve working conditions. Those who regard the owners as their enemies encourage activism, including strikes, to try to achieve necessary concessions. The character of Étienne Lantier represents the working class as fundamentally opposed to the owners, as he advances his Marxist position. The strike crystallizes the multiple dimensions of class antagonism at the mines. The murder of Lantier’s friend Maheu by the strike-breaking soldiers is one episode that illustrates the depth of that antagonism. As agents of the owners and the state, the soldiers consider themselves of a super status than miners, and do not hesitate to do the owners’ bidding.