The state of Arizona has passed a tax reform bill that taxes property owners at a specified rate with the exception of mines and utilities. Both mines and utilities are assigned a higher rate of tax for their properties. A state legislator commented on the bill, "In some of these small towns, without the higher rate of taxation for mines and utilities, the schools in these towns would suffer because the property is worth nothing and there are no property tax dollars coming in. We have to tax these area's wealthiest citizens at a different rate and those citizens happen to be the mining companies and the public utilities." Is the tax constitutional?