Pennsylvania environmental regulators have fined a natural-gas driller more than $3.5 million for violations at 10 well sites and six pipeline locations. The Department of Environmental Protection said Wednesday that subsidiaries of Rice Energy Inc. operated an unpermitted wastewater impoundment that leaked, improperly constructed wells, violated rules for erosion and sediment control, failed to obtain permits and committed other infractions. Regulators say the violations took place over several years at sites in Washington and Greene counties, in western Pennsylvania. Canonsburg-based Rice has already paid the fines. DEP has entered into several agreements with Rice and says the company has either fixed or is scheduled to fix the problems at its wells and pipelines. A Rice Energy spokeswoman did not immediately return a call for comment.