I like that a few folks are killed offscreen in this film. It's a refreshing break from the usual bloodbath we get in a lot of horror movies.
You've seen Guy Standeven in something because the man was in everything.

Off screen kills are:

1. Edgar - dies of dehydration "thirst". We know exactly how he died but it's still off screen in terms of actual death.
2. Construction worker #1. Dragged up the hill and likely devoured, but off screen.
3. Construction worker #2. Rocks fall on him and hear the crow bar drop.
4. Power Company. "They'll send someone after they see the roads are down and the power is out." "Yah that's how it works." And then it pans to their truck with two bloody helmets.
   My Dad and I for the longest time never understood that scene, thinking it just panned back to the two dead construction workers, only I later realized it was the power company.

That's what I recognized it as, too.

It's a device for phone line testing. A type of specialized phone.

I never even noticed the colour of the helmets. I think the phone is just a CB radio made to look like a phone for aesthetics.
10 kills and a whole flock of sheep massacred To paraphrase The Baconator:
"This film is getting violenter by the minute!"
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Well the first two construction guys we see working on the highway are wearing white helmets. The later scene with the pickup truck the two helmets on the ground are yellow. If you notice there is also a small 80s style hand phone laying there too, which had me thinking they were probably utility guys working on the communication lines.
Just a guessbut would mean the body count for the movie is 10 and not 8.

Not 100% sure, but I get the impression that the helmet was from a 3rd guy who was sent to check up on the first two utility guys.
We start off with 2 guys by a truck, one of which gets dragged up the hill and (fairly safe to say) eaten whole, probably including helmet. 2nd guy was crushed under the landslide, so his helmet would likely be buried. The truck itself was to the left of the hill as you face it, and unless it was a massive job with whole swathes of machinery needed, 1 truck would be enough to transport them and the pneumatic drill and a few other bits.
Later on, we see a 2nd smaller truck to the RIGHT of the landslide. And even later Val and Earl see the bloodied helmet, when the first 2 are accounted for.
So, yeah I think 3 people were killed there. 2 by Graboid, and the last by suffocation/crushing/whatever fatal condition resulting from landslide.
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