The best I've been able to do is find that your two people mining the copper and manufacturing the copper pipe work in the primary and secondary industries of the economy.
Primary: involves the retrieval and production of raw materials, such as corn, coal, wood and iron. (A coal miner, farmer or fisherman would be workers in the primary sector.)
Secondary: involves the transformation of raw or intermediate materials into goods e.g. manufacturing steel into cars, or textiles into clothing. (A builder and a dressmaker would be workers in the secondary sector.)
I've had a little luck finding names for people who work in the primary sector:
Primary producer A person or organization producing basic agricultural
commodities, such as a farmer or cattle producer.
A primary producer is an individual, partnership, trust or company
operating a primary production business if they undertake:
plant or animal cultivation
fishing or pearling
tree farming or felling
Australian Taxation Office
The problem is these terms are no good. I've only found very few of these, and none for secondary producer. Also, primary producer usually refers to biological organisms, such as photosynthesising plants etc.
So the best I can come up with is:
someone working in the primary sector of the economy
someone working in the secondary sector of the economy
Also the producer/manufacturer distinction doesn't work, because you can produce copper pipes. Hopefully someone can find a term for "gatherers of raw materials" and another for "those who turn raw materials into goods/products."