(a) The board shall have the power and duty to:

(1) Provide for the collection of all moneys in connection with this chapter;

(2) Provide for the payment of all administrative expenses;

(3) Hear and decide all applications for retirement benefits under this chapter;

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

(5) Make all necessary rules and regulations not inconsistent with the laws of this state for its government and for the government of the employees who are employed to administer this chapter;

(6) Determine and fix rules of eligibility of persons to receive retirement benefits under this chapter;

(7) Make provisions for refunds and repayments to persons who may be entitled to receive them;

(8) Keep records of all its meetings; and

(9)(A) Subject to the terms and limitations of this Code section, 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 5 of this chapter for persons retiring under this chapter. Such method shall be based upon:

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

(ii) 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

(iii) 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.

(B) No increase granted pursuant to subparagraph (A) of this paragraph shall exceed 3 percent of the maximum monthly retirement benefit then in effect. Thereafter, such increases may become 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.

(C) No increase pursuant to subparagraph (A) of this paragraph shall become effective within six months of the effective date of any increase in the maximum retirement benefit granted by the General Assembly pursuant to Code Section 47-14-70.

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