The word "volunteer" from Korea Overseas Volunteer, itself, implies sacrifice innately. When it comes to engineering, my volunteering should be considered as technical cooperation, I think. Enumerating what I did at that time, I repeated introducing new technology, persuading its implementation, making MOE staffs understood from training, following up progress, and discussing issues to escape from stalemate that most of KOVs were prone to encounter in the middle of cooperation. That's it! Interacting with local staffs was the very virtue of volunteerism.
I returned back to Korea, November 2001. My juniors took over duties and are still managing their KOV operations very well. Refer to this link
for more details. Photos below are snapshots taken while staying there (years of 1999 ~ 2001)
Photo set here