Hi, I made an upgrade to the visuals for this mod. Namely, I put a 3 pixel wide black square around the excavators, to show where the boundary of the physical object is. I'm not sure how to give you the two .png files, but I'll attach them to this post if I can. Otherwise, I'll put them on imgur.

Highres: https://imgur.com/pZ6kuWn
Normal res: https://imgur.com/G3HNBxj

I do appreciate your efforts in making a clearly visible Border. I fancy with that, too. But imho just a black line doesn't cope with the quality of the models.
Also: The collision box does not begin on the outskirt of the parcels, but 12px(HR)/9.6px(LR) inward from all 4 directions.
I also can't just make the collision box smaller, because the game will then complain that the fluid connection is outside of the collision box

So it turns out I didn't have e-mail notifications on and I never realized you'd replied. If you'd have bothered to download and test with the images I included you'd realize that I did indeed put the black bars in the correct spots inset from the total mining area. The black bars really do outline the exact collision box of the miner. I am somewhat offended you told me I'm wrong without even bothering to check my work. I was trying to help you. I agree, the black bars are not an elegant solution, but they are functional. Art isn't my strength, but neither is frustration. I'm happy to send you the PSD files I used so you can replace the black bars with something more visually appealing to you.

As for fluid connections, the black line goes right through/is in line exactly with the end of the fluid connection, so it looks completely correct. Seriously, download the PNGs and boot a game up with them, you'll realize they're super helpful when placing down fields of these damned things. Until then, I'll just keep the black bars in my local copy, and if anyone here asks, I'll fork your project and make a version with black bars so the people can vote with their mod downloads.

Believe it or not: I did download and test both of your images in both resolutions. And from these observations I wrote my reply to you. You being offended is not my problem, but yours. I'm replying to the points you bring up.
The black bars do >>not<< line up with the 'collision box'. In the following picture you can see the collision box as a thin red lined square inside a blue square. The blue square shows the 'selection box'. Directly aligned to the blue square you can see the black outskirts of your modifications. Since your black bars do not align with the red square, they also don't line up with the 'collision box'.
https://imgur.com/mHCheAW
On the programmers side they are defined as:
collision_box: [(5.2, -5.2),(5.2, 5.2)]
selection_box: [(-5.5, -5.5),(5.5, 5.5)]
Just in case you were talking about the 'selection box': You will notice the yellow corners marking them, when colliding with other buildings they will turn red and help you guide them in the right place.

In my first review I missed the bar crossing the top pipe. visual:
https://imgur.com/1Tjl2TH
Green is somewhat acceptable, but still noticeable (due to the vertical alignment). Red on the other hand is too visible. That's a big no for me.

"(...) I'll fork your project and make a version with black bars so the people can vote with their mod downloads."
Why not add black jack and hookers? /s
Seriously: For me making mods is not a competition for popularity.