During the early morning hours of 20 March 1969 the Battalion, One Four minus Bravo-3 which was OPCON to 3rd Battalion 4th Marines on Dong Ha Mountain, was alerted to commence the assault on Fire Support Base Argonne at 1000 hours.  Prior to the assault an extensive artillery and air preparation of the objective was completed.  Prior to L-Hour a reconnaissance team was inserted to insure a secure LZ.  Two helicopters were assigned to insert the team.  Only one aircraft landed.  It received a heavy volume of fire which killed both pilots and wounded all the reconnaissance team members.  The order to land the assault element was given and Delta Co. commenced the helicopter assault landing on the lower LZ at Fire Support Base Argonne due to the upper zone being fouled by the downed reconnaissance helicopter.  Delta Co. met with stiff resistance from bunkers.  The assault continued throughout the afternoon and by night fall the hill was secured with scattered sniper fire.  Delta Co. and the Alpha Command Group maintained a continuous vigil throughout the night prepared to repel any counter attack.

At 0800 on 21 March Mike Co. of 3rd Battalion 4th Marines was chopped OPCON to One Four and assumed responsibility for security of Fire Support Base Alpine from Charlie Co.  At 0820 the first round of an enemy 82 mm mortar attack instantly killed Lt/Col George T. Sargent, the Commanding Officer and 2nd Lt. Carl R. Wilson Jr., the Battalion S-2 Officer.  The same round wounded many other Command Group personnel.  

Major H. E. Pierpan, Battalion S-3 Officer, assumed command of the Alpha Command Group and directed operations at Fire Support Base Argonne.  Major J. E. Green, the Battalion XO, monitored the situation with follow up elements on Fire Support Base Alpine.  Lt/Col C. E. Wilcox assumed command upon his arrival at Fire Support Base Alpine about 1400 hours on 21 March 1969.  Accurate enemy 82mm mortar and sniper fire hampered helicopter operations at Fire Support Base Argonne.  Counter mortar fire against suspected enemy positions continued throughout the day and into the night.

On the afternoon of 21 March Alpha and Charlie Companies were landed south of the Fire Base Argonne and commenced movement north to relieve the pressure on Argonne.  A flare ship provided continuous illumination during the night.  Additionally an aerial support ship (Spooky) assisted in suppressing enemy mortar fire and deterred a night counter attack.

At 1430 hours 22 March the partially constituted Bravo Command Group from Fire Base Alpine and the Commanding Officer Lt/Col Wilcox arrived at Fire Base Argonne.

On 23 March patrols from Delta Co. were in frequent contact with the enemy less than 200 meters outside the north perimeter.  Charlie Co. arrived at Fire Base Argone and was resupplied and dispatched to search and clear the area to the direct north.  Helicopter flights into Fire Base Argonne continued to be endangered by the sporadic mortar attacks coinciding with the arrival of the helicopters at Fire Base Argonne.  Bravo Co. was deployed to activate Fire Base Green at Grid XD 758610.

At 0815 hours on 24 March Charlie Co. at Grid XD 677577 searched and cleared the seven bunker complex in the same area that contact had been made on 23 March.  Five NVA bodies previously undiscovered were found at this position.  The bunkers were destroyed and air strikes were called to assist in the total destruction of those well prepared emplacements.  At 0900 hours Mike Co., attached from 3rd Battalion 4th Marines, searching the suspected area made contact with an unknown size enemy unit and received one friendly KIA and inflicted three enemy KIA's.  Two AK-47 rifles, six Chicom grenades, twenty rounds of 82mm mortar and three helmets were captured.

At 0930 hours on 25 March, Alpha Co. received sniper fire and called in air strikes resulting in four enemy KIA.  At 1100 hours while resupply helicopters were landing supplies at Fire Base Argonne, nine enemy 82mm mortar rounds landed in the vicinity of the upper landing zone and Battalion Command Post.  Alpha Co. was ordered to close on the suspected position and destroy it.  At 1310 hours Alpha Co. assaulted a bunker complex killing seven enemy.  There was an extensive air and artillery preparation just in advance of Alpha Co.'s sweep of this area.

Alpha, Charlie and Delta Co.'s continued to search and clear the area in the immediate vicinity of LZ Argonne on 26 March.  There were no additional fire incidents.

Throughout the daylight hours of 27 March, several attempts were made to resupply Fire Base Argonne.  All attempts failed due to incoming 82mm mortar fire in the landing zone.  The Commanding Officer and XO both received minor shrapnel wounds and remained on Fire Base Argonne.

During early morning hours on 28 March, Alpha Co. was probed by an estimated squad of NVA.  That night an aerial support ship (Spooky) was requested and inflicted one enemy KIA and three probable.  Later the same day Alpha Co. found an NVA mortar position and several 82mm mortar rounds, fuses and increments.  Also found were a bipod for a .50 cal. and a 12.7mm gun sight.

At 1705 hours on 29 March, Alpha Co. found at Grid XD 666574 an enemy company size position.  There were nine NVA bodies, forty to fifty bunkers, four AK-47 rifles, sixteen hundred AK-47 rounds, twenty eight E-tools, five 60mm mortar rounds, fourteen RPG rounds, thirty-three Chicom grenades, sixteen AK-47 magazines, fifty pounds of rice and numerous articles of clothing and personal field equipment.

As the month ended the three companies of the battalion remained heavily engaged with a determined NVA force, who were deadly accurate with 82mm mortar fire.  Bravo Co. continued its construction of Fire Base Green at Grid XD 758610.  Mike Co. continued its defense of Fire Base Alpine with regular sweeps in a radius of three to four kilometers.

April began with the battalion heavily engaged with a stubborn NVA force in the area surrounding Fire Base Argonne in the Purple Martin AO.  One company continued clearing for and construction of Fire Base Green at Grid XD 758610.  Delta Co. was assigned security for Fire Base Argonne while Alpha and Charlie Co.'s searched the surrounding area for NVA and hostile mortar positions.  On the first of April, Fire Base Argonne received enemy 82mm mortar fire on four different occasions.  Alpha Co. moved immediately to surround the suspected area of the origin of the mortar fire in the vicinity of Grid XD 662578. 

On 2 April a platoon size patrol from Alpha Co. made contact with an NVA force in a bunker complex vicinity of Grid XD 666569 resulting in one NVA KIA.  Early in the afternoon the Alpha Command Group on Fire Base Argonne received thirty rounds of enemy 82mm mortar fire.  That same day a platoon patrol from Bravo Co. in the vicinity of Fire Base Green spotted three NVA in the open.  Artillery fire was called with unknown results. 

On 3 April the Alpha Command Group and Charlie Co. commenced a helilift from Fire Base Argonne to Fire Base Green under constant harassment from enemy 82mm mortar rounds.  The lift was completed with negative casualties and officially Fire Support Base Argonne was closed although Delta remained overnight and moved off at first light on 4 April.

The next morning, 4 April 1969, found Delta Co. moving off of Fire Base Argonne in a northeasterly direction and Alpha Co. continuing its movement to the south sweeping in the valley leading east to Fire Base Alpine.