The overseers treated the Chinese workers like slaves by whippings

The Chinese worked longer and harder than whites, but received less pay: because the Chinese had to pay for their own board, their wages were two-thirds those of white workers and a fourth those of the white foremen. (Even the allocation for feed for horses—fifty dollars a month for each—was twenty dollars more than the average Chinese worker earned.) Worst of all, they endured whippings from their overseers, who treated them like slaves. (Chang 61-62)