Which of the following is true of unions formed during the mining booms in the West? [Select all that apply.] Which of the following is true of unions formed during the mining booms in the West? [Select all that apply.] Unions were originally formed by miners to combat working in extremely unsafe conditions for very low wages. Unions eventually replaced saloons as the most important institutions in mining communities. Unions ultimately proved to be ineffective at helping miners receive better treatment. Unions established hospitals to treat injured miners