Final answer:
The man who took over the gold mine was the younger brother of the previous manager. He led a group of people who were deceived into thinking slavery was still legal. This situation developed during the California Gold Rush, when mining operations became more complex and required significant investment and technology.
Step-by-step explanation:
The man who ran the gold mine after they fired Bob was his younger brother. In the narrative given, this younger brother is put in charge of a coloured following, which were a group of people misled to believe that slavery had not been abolished, under the deceitful proclamation that the South had won over the North. During the California Gold Rush, independent miners were often outpaced by companies with the resources to employ hydraulic mining technology. This shift occurred when the easily accessible placer gold ran out, and the remaining gold was situated deep underground, requiring advanced equipment and organized labor to extract.