Drilling rates depends on lots of factors the biggest one being the consistency of rock hardness and length of holes. The slow part of drilling is the top of the hole where you have to 'set up' on the hole and case through the overburden. It can take the better part of a 12 hour shift do this. On a lake it can take just as long since you have the same setup issues plus you need to put supports/slings in the water to support the casing and drill string. Lots of farting around depending on water depths.

in stable rock you can easily drill 100-150 meters a day. I've seen over 200m/day. As holes go past 300 things start to slow down as each core tube pull takes longer and does each bit change where you have to pull the core string. As holes hit the 500-800 meter length drilling start to slow down to 70-100 m/day and even less as the holes get deeper.

There are no absolutes. Highly fractured rock can have you pulling core many times a shift, changing bits, etc with little production to show for it. Similarly drill bits are designed for specific rock hardness. If you are drilling through different type of rock with different hardness what works well in one rock doesn't in another and you need to change bits. Add in broken drill strings, drill rod 'dropped' down a hole, and a host of other surprises, and it makes predicting drilling rates difficult.

Once the drill crews have experience with a deposit drilling typical rates tend to get better.

As to lake ice it typical freezes around the edge first and then out to the deeper parts. Once frozen the centre freezes thickest. As with ice cubes lake ice is less dense then water so if floats which results in fracturing around the lake edges and flooding/slush. This season with the minus 20's there will good ice everywhere so they should be on the ice as soon as the want. I bet if you were near the lake tonight you could hear the cracking from stress fractures as it gets thicker.

If they are using heavier rigs for deeper drilling they may wait a bit but with the cold we have been having I suspect there is enough ice right now.

.... Been there