(a) The board is given the following authority, powers, and duties:

(1) To contract with proper federal authorities for old-age, survivors, and disability insurance coverage under the Social Security Act;

(2) To provide for the collection of all moneys provided for in this chapter;

(3) To provide for the payment of all administrative expenses;

(4) To hear and decide all applications for retirement and disability benefits provided for under this chapter;

(5) To adopt such tables as it shall deem desirable in connection with the proper operation of the retirement system;

(6) To provide for the payment of all retirement and disability benefits that may be determined to be due under the rules and regulations as adopted by the board;

(7) To make and promulgate all necessary rules and regulations, not inconsistent with the laws of this state, to carry out this chapter and to distribute such rules and regulations to members of this retirement system;

(8) To determine eligibility of persons to receive retirement benefits and disability benefits under this chapter;

(9) To make provisions for refunds and repayments to persons who may be entitled to receive them; and

(10) To keep records of all of its meetings.

(b) (1) Subject to the terms and limitations of this subsection, the board of trustees is authorized to adopt from time to time a method or methods of providing for increases in the maximum monthly retirement benefit payable under Article 7 of this chapter for persons theretofore or thereafter retiring under this chapter. Such method shall be based upon:

(A) The recommendation of the actuary of the board of trustees;

(B) The maintenance of the actuarial soundness of the fund in accordance with the standards provided in Code Section 47-20-10 or such higher standards as may be adopted by the board; and

(C) Such other factors as the board deems relevant. Any such increase may be uniform or may vary in accordance with the time of retirement, length of service, age, nature of the retirement, or such other factors as the board of trustees shall determine.

(2) No increase granted pursuant to paragraph (1) of this subsection shall exceed 3 percent of the maximum monthly retirement benefit then in effect. Thereafter, such increases may be authorized effective as of January 1 and July 1 of each year; provided, however, that no such increase shall exceed 1 1/2 percent of the maximum monthly retirement benefit then in effect.

(3) No increase shall be made pursuant to paragraph (1) of this subsection to become effective within six months of the effective date of any increase in the maximum retirement benefit granted by the General Assembly through amendment of Article 7 of this chapter.

(c) The board shall also have all other powers necessary for the proper administration of this chapter.

(d) Subject to the terms and limitations of this subsection, the board of trustees is authorized to adopt from time to time a method or methods of establishing an employee contribution rate lower than as established in Article 5 of this chapter; provided, however, that such rate shall not be lower than 6 1/2 percent. Such method shall be based upon:

(1) The recommendation of the actuary of the board of trustees;

(2) The maintenance of the actuarial soundness of the fund in accordance with the standards provided in Code Section 47-20-10 or such higher standards as may be adopted by the board; and

(3) Such other factors as the board deems relevant.

(e) Notwithstanding the provisions of subsection (d) of this Code section, no member who becomes a member of this retirement system on or after July 1, 2009, shall be entitled to receive any postretirement benefit adjustment.