Apologies for digging this one up again!
Those containers on the 20ft flats, are they standard open top containers? They appear similar to the 20ft coal boxes that were used on the Cawoods traffic.
When did the Tara traffic change from these wagons to the current ex-shale type wagons (approximate year, not day, date, time!)
Are there any photographs of either the loading at Boliden's or the unloading* at Alexandra Rd? If you'd rather not post, any PMs will be treated with the utmost discretion.
I'm guessing it would be a tippler arrangement because those wagons don't appear to be conducive to unloading by shovel.