While its good to know that you have created a portfolio with long term horizon, IMO nobody knows how market will behave over 50 year period. A periodic look over ones' allocation will help gauge whether your decisions are sailing in the right direction.
Regarding your portfolio, I am sure you know the best thesis to invest, esp. NMDC the margin of safety has greatly eroded with prices going haywire and dividend yields declining, its no longer a cash cow these days.
BTW curious to know ur rationale for igarashi motors (delisting?) and kse
Regards
Sreekanth