Copper had been mined in the US for thousands of years, but large-scale commercial mining of copper took off starting in the late 1800s. This was due to several factors. Technological advancements in the mining industry led to improvements in the production of copper. This helped the country keep up with the growing number of people wanting to buy copper starting in the 1890s. At the same time, the growth of the railroad system made the transportation of copper in large batches much easier. Several states saw rapid growth in the production of this resource, for example: ______blank