Initiative 9, the "District of Columbia Mandatory-Minimum Sentences Initiative of 1981," will be the only question to appear on Sept. 14 primary ballots.

It proposes amendments to both the D.C. Code and the 1981 Uniform Controlled Substances Act that would provide fixed prison terms for drug traffickers and persons who commit crimes while armed with guns.

If approved by the voters, the initiative, like all routine D.C. legislation, would go to Congress for a mandatory review. Unless Congress rejects it within 30 legislative days, the initiative would become law.

If the measure becomes law, persons convicted for the first time of using a gun during the commission of a crime of violence would be imprisoned for a mandatory minimum term of five years and could not be released on parole or granted probation or a suspended sentence until that five-year term is served.

Repeat gun offenders would be subject to a mandatory 10-year minimum prison term.

The new law would not apply to persons sentenced under the federal Youth Corrections Act.

That law allows judges to sentence defendants under the age of 22 to an indeterminate prison term at the Lorton Youth Center or elsewhere.

Crimes of violence, as defined in the D.C. code, include committing or attempting to commit murder, rape, kidnaping, burglary, robbery and assault with a dangerous weapon.

The mandatory minimum penalties would apply regardless of whether shots were fired during the crime.

The proposal also would add a new section to the Uniform Controlled Substances Act imposing a mandatory minimum sentence of four years on any person convicted of selling or distributing illegal narcotic drugs, such as heroin.

Persons convicted of selling or distributing illegal non-narcotic drugs, such as cocaine, phencyclidine (PCP) or barbiturates would face a mandatory minimum prison term of 20 months.

Convictions resulting from the sale of other controlled substances, such as marijuana, would carry a mandatory minimum jail term of one year if the retail value of the substance exceeded $15,000.

The proposal would allow judges to waive the mandatory sentencing provisions for first offenders who are drug addicts at the time of the violation and who sold or distributed drugs to help support the habit.