1. Every person, partnership, association, corporation, whether organized under the laws of this or any other state or country, company, mutual company or association, the parties to any interindemnity contract or reciprocal plan or scheme, and every other insurance carrier, insuring employers in this Commonwealth against liability for personal injuries to their employees or death caused thereby, under the provisions of this title, shall, as hereinafter provided, pay a tax upon the premiums received, whether in cash or notes, in this Commonwealth or on account of business done in this Commonwealth, for such insurance in this Commonwealth, at the rate of 2.5 percent of the amount of such premiums.

2. However, premiums received for insuring liability which exists concurrently under this title and the Federal Coal Mine Health and Safety Act of 1969, as amended, shall be modified in accordance with an equitable premium modification plan approved by the Commission. Such tax shall be in lieu of all other taxes on such premiums, except as provided in §§ 65.2-1101, 65.2-1201, and Chapter 4 (§ 38.2-400 et seq.) of Title 38.2, and shall be assessed and collected as hereinafter provided. But such insurance carriers shall be credited with all cancelled or returned premiums, actually refunded during the year on such insurance, and with premiums on reinsurance assumed.