Not Minor Maintenance !
The actual work being carried out is re-surfacing and replacement of all light fittings. Due to the fact that works can only be carried out at night, it will take several months to complete, during which time the runway has to be downgraded to Cat 1.
It is being carried out during the summer as low vis incidents are less likely, but due to s*d's law it will sometimes occur, causing disruption. Unfortunately there's no real alternative to carrying out this type of work with only one main runway available (How about a 2nd ? - Now there's an idea!)