Non-renewable resources are resources for which there is a limited supply. The supply comes from the Earth itself and, as it typically takes millions of years to develop, is finite. Non-renewable resources can generally be separated into two main categories; fossil fuels and nuclear fuels.
But there were pockets of the North on the eve of the Revolution where slaves played key roles in the economic and social order: New York City and northern New Jersey, rural Pennsylvania, and the shipping towns of Connecticut and Rhode Island.
The Portuguese and Spanish were already dealing in slaves from thrir trading posts along the western coast of Africa. This was the beginning of the Atlantic slave trade. The first captive Africans were sold as slaves in Santo Domingo (1503). Slavery was not a major institution in the early Spanish colony.