There was also a time when an alum gave a huge amount to Mines and IIRC, it was in petroleum engineering, so majors were receiving big scholarships from that department.
I know recent grads who work in oil and gas, work on oil platforms and travel across Montana for a couple of weeks of the month. They make a lot of money quickly but then want a different lifestyle. I think most are chemical engineers, not specifically petroleum.
CU is known for aero, Mines for petroleum and other hard rock (and blowing things up), and CSU for agricultural. They all have the base courses in mechanical, civil, chemical, and electrical (and now computer). I have a nephew who went to CU in mechanical, and I don’t think he took one class in Aero, but he works for Northrup and originally worked on a moon project. His wife is a water engineer (civil) and that may be a stronger major at CSU, but her family is a ‘CU family’ so she picked CU. Another nephew is at Mines, also mechanical, and I have no idea what area he’s interested in. He picked Mines over CU mostly because Mines gave him a lot more money, and he plays club hockey. I think if the money had been equal he would have picked CU because he wanted a marching band but he’s happy where he is.
But for aero, CU has more bells and whistles, a building that is shaped like an airplane, labs with parts of jet engines and rockets, and boasts a few astronauts as grads.