Access road in rocky terrain: skid steer or mini excavator?

[bcastle]

So I need to put in an access road to some very remote property in the Colorado rockies this coming Monday. The nearest exisitng trail will have the road I build be around 1800' long with a total climb of around 450' along the way. The soil is very rocky and hard with very little clay.

I'm leaning towards renting a 7,900lbs mini excavator (Bobcat E35) to do the job. I am expecting it to take 2-3 days, but the rental place charges the same for 1 week as they do 3 days so I realistically could take a full 5 days if needed.

There are definitely spots with massive rock I will have to go around, but how well do these things dig up rocks?

I personally think a skid steer would do hardly anything in this soil, but all my experience is limited to the smaller machines. Maybe a larger skid steer with tracks would do better than what I think?

Thanks for any and all opinions and insight!

 

[crashz]

The excavator will do better with the rocks and any roots or stumps, but its slower to move piles and such. If you are grading and ditching and leaving the spoils pretty much inplace, it will be faster. A skidsteer is not much of a digger.

1800 ft is not long, but that is a steep slope to work on. Be careful!

 

[jeff9366]

There are definitely spots with massive rock I will have to go around, but how well do these things dig up rocks?

I would reserve a heavier excavator than you are contemplating, for stability. Safety first.

I rented a Bobcat E35 and found it inadequate for excavating Oak stumps in a reasonable time. I wanted individual stumps out in twenty minutes each, tops.

 

[CWB Wyo]

I don't have a answer to your question. Just curious about what part of Colorado you're talking about?
CWB.

 

[EddieWalker]

that's a pretty small excavator. Can you get a bigger one? I wouldn't even think about a skid steer. They are horrible at everything, but small and easy to get from place to place, and better then nothing.

 

[grsthegreat]

Personally when i built my roads i rented a case 850 dozer. Did about 900 feet of road in a day

 

[Ken45101]

What size rocks? A mini-ex isn't very good at digging out large rocks, especially if they are packed in solid.

Also, working going uphill is more difficult.

Absolutely make sure it has a hydraulic thumb!

I have a 9000# mini ex that I use for building trails. In 90% of the situations it is my machine of choice vs. a skid steer, but large rocks and working uphill are difficult (even worse for the skid steer.)

I agree with the suggestions of a larger excavator or a dozer...with an experienced operator!

 

[rScotty]

So I need to put in an access road to some very remote property in the Colorado rockies this coming Monday. The nearest exisitng trail will have the road I build be around 1800' long with a total climb of around 450' along the way. The soil is very rocky and hard with very little clay.

I'm leaning towards renting a 7,900lbs mini excavator (Bobcat E35) to do the job. I am expecting it to take 2-3 days, but the rental place charges the same for 1 week as they do 3 days so I realistically could take a full 5 days if needed.

There are definitely spots with massive rock I will have to go around, but how well do these things dig up rocks?

I personally think a skid steer would do hardly anything in this soil, but all my experience is limited to the smaller machines. Maybe a larger skid steer with tracks would do better than what I think?
Thanks for any and all opinions and insight!

Are you sure about those numbers? Because if that's right, you are making an incredibly steep road. Drainage is going to be an issue. In fact, just getting up and down with a load in the best dry summer weather is going to be an issue. In the Rockies that ill be a summer-only road, right?

Of course any job can be done with small equipment - it just takes longer. But even with modern equipement your time for this job seems way low. I doubt that the skidsteer or that tiny excavator you are looking at will do much. For reference, that size excavator will dig well in dry ground but not at all in rock. Rocky Mountain often means fractured granite rock right starting a few feet under the surface.

You ask about the capability of that size excavator.... For moving & stacking rocks - with a thumb - that size excavator will move and stack rocks up to medium suitcase size all day long with ease, It will struggle hard with footlocker sized rocks but can eventually get one end up and tumble them into position even if it can't actually lift them. Anything larger is too much to do much with. About the only job worse than what you are describing would be if you were trying to put that road across a rocky side slope. Doing that would be much harder & take longer even though not as steep when finished.

As described, I'd recommend a dozer with 6way blade and a skilled local operator to do the cutting plus something with a bucket to move dirt. And even so allow more than 2 or 3 days. And if you can find some way to make the road twice the length for that rise you'd have a better chance at using it in the winter. Not trying to discourage you, just being realistic.
rScotty

 

[EddieWalker]

The problem with a dozer in rocky terrain is that it's horrible at digging out the rocks.

 

[rScotty]

The problem with a dozer in rocky terrain is that it's horrible at digging out the rocks.

Hey Eddie, here It's not individual rocks in dirt like central Texas - or even layered shelf rock like Lampasas County. What we've got in the Rockies is usually a layer of fractured and disintegrating granite down for a couple of feet under a foot or so of what we call "top soil" but is really just mostly rotted pine duff. The disintegrating granite (DG) has been broken up by water/freeze cycles and so it is pretty easy to fracture it farther and scrape it out with construction type machines. The DG can be scraped out by a skilled dozer or excavator....even a backhoe. But that's about as far as we can go because only a few feet farther down we get into the same stone but unweathered. That is what is called "competent granite".... which means all one piece and not fractured. No way can you do anything to it. That's the rock that forms the backbone of these mountains. Then nothing but blasting will work.
rScotty