The correct answer is false.
American mines, mills, and factory workers were not protected by laws before the 1850's. Since the government took a laissez faire (aka hands off approach) there was very little rules and restrictions on businesses. There was no: overtime laws, laws against child labor, minimum wage, laws about working hours, etc. All of these decisions were left up to the individual business owner.
The horrible working conditions in the aforementioned places would not really change until the Gilded Age (late 19th century-early 20th century). This time period saw the rise of organized labor and increased government regulation.