i have some doubts that what you saw was a MBRL system in first place.
If you can explain barrel size/length etc it might help. However I am unaware of any ongoing project to convert Type-59 into MBRL systems so I bit skeptical, not that I know about ALL ONGOING PROJECTS.
I did a detailed article and ran a thread on these a few years back. Was in the factory where these were being manufactured. Unfortunately the pics have been deleted from internet and i do not find them on my PC anymore either so all that data is essentially lost.
Here is the link:
https://defence.pk/threads/de-mining-equipment-of-pakistan-army.125394/