Excavation curiosity

[HiTechTed]

I wanted to throw out an excavation question for those of you who are skilled in the art of excavation.

My attached picture (made hastily with Paint, sorry) shows kind of what I am wondering about. It's a cross-section of an area of land that has a 5 to 6 foot drop off. The area in gray would be removed, leaving the area in white.

The only piece of equipment available is a Bobcat mini excavator that will dig about 8 feet deep.

Given that piece of equipment, how would you tackle the job? My thought was to start at the red dot and dig down maybe a foot or 2, moving back (to the left) and repeat. I have no idea if this is the best way to do it.

With this scenario, how would YOU go about doing this job?

 

[beenthere]

Looks like a plan. But factor in where you want the spoils to end up as you dig. Might alter your plan.

 

[magicheater]

How wide is the area to be excavated? This will determine the volume and then you will be able to decide if the machine you have is economical. If the area to be excavated has a 5-6' drop off, where does this occur? AND as been there says, where are you gonna put the dirt!

 

[tony Cecil]

Just assuming it is twenty feet wide, I would start at the other end, as It would be difficult to return to the deep end if something changed....This is where a skilled operator would come in handy Tony

 

[GE222]

Depending on the operator and soil conditions, a Bobcat mini excavator, I am guessing maybe a 325, should be capable of negotiating the incline if the slope doesn't come out quite right the first time.

 

[captaincrab55]

How wide is the area to be excavated? This will determine the volume and then you will be able to decide if the machine you have is economical. If the area to be excavated has a 5-6' drop off, where does this occur? AND as been there says, where are you gonna put the dirt!

Great advice fom magicheater & been there..... Call a contractor for a free estimate and pick his brain some... Till you tell us how wide and where you going to place the spoil, one can only guess...

 

[HiTechTed]

The reason I mentioned the Bobcat machine is because I can use it for free (I pay for fuel). As for the spoil, I will probably have to pile it within reach and then move it out as I go along. I will guess that the area in question is roughly 200 feet long...I might be over-estimating that. The way the drop off is, I can't work it very well from the other side so I would need to work from the top.

Thanks for the replies so far!

 

[Redneck in training]

200 ft long. That is about 15000 cuft. That is about 3 to 4 days of work for big bulldozer depending how far you need to move the spoils. It will be quite big job for the mini-excavator. If you count 30 seconds per bucket it will take you more than 100 hours just digging.

 

[captaincrab55]

The reason I mentioned the Bobcat machine is because I can use it for free (I pay for fuel). As for the spoil, I will probably have to pile it within reach and then move it out as I go along. I will guess that the area in question is roughly 200 feet long...I might be over-estimating that. The way the drop off is, I can't work it very well from the other side so I would need to work from the top.

Thanks for the replies so far!

Ted, Do the Math, you have way to many Cubic Yards of spoil to handle using that machine... That spoil will be handled way to many time with that mini ex... Reminds me of a friend that wanted to use my wood shop to make a standard/stocked mouldind to save a few $$.. He was retired and his son was building a house.. He was going to rip the wood down from larger pieces of wood, then planned on using my moulding cutters to mill it.. All this to save $$, because he was retired.. He had it all figured out as to how many $$ he could save his son.. I then asked how he was going to transport the finished product 2 hours away.. He figured he could use my truck with the ladder rack... I put my foot down there on that project knowing what it was going to cost me... He didn't plan on buying or getting any cutters sharpened, nor did he plan on buying gas or paying for the shop electric.. At the time I has a business going good and he figured I could write off all of that.. The wood shop was my hobby shop @ home.. He borrowed the truck many times before and never bought gas.. He didn't talk to me for a few years... Long story short, does the person lending that machine know how many hours it will take.. Don't forget that the machine will need an oil change, greased daily, and who pays for repairs if it breaks down... Check out what a new track costs for that machine ??? If you get hung up on something sharp and the track gets trashed, somebody will be out BIG $$...

 

[HiTechTed]

Actually, the person lending the machine is related to me and doesn't care how long I use it. I can do the oil change, and pay if something breaks...it's not like I'm taking advantage of anybody, it's all good as far as the machine goes. I let the guy hunt on my land and I have told him up front that I will take care of the maintenance, etc.

As far as moving the dirt, that IS a PITA. I really need a dump truck or trailer so I'm not "handling" the dirt 2 or 3 times, and I might acquire one or the other of those sometime soon if my luck holds out. I didn't plan on doing it all at once and it's not a critical job (plus I'm not charging myself $90 an hour for my own time). I would like the experience with the machine. It can't hurt to learn something, and since it's not a foundation or a septic system I'm digging (which I definitely would NOT do myself), I don't have to be dead-perfect.

Please break the project into 20 foot or 40 foot chunks and then tell me how you would go about it. I could do a little every so often, in between other things around here, and eventually finish it up. I can also find a home for every bit of the dirt so that's not an issue, either. My only real "issue" is not knowing what technique to use to get the best results given what I have on hand to do the job with.

Thanks!

 

[beenthere]

Start slow and at the point you marked. Decide if you want to stay on the edge and go the full 6' down before backing up to take the next bite. That should keep you "on the level".
Or if you want take less than the full depth and back up the full width, but know this will entail getting on the slope with the excavator to take the next course off.
You will need to access the risk of the edge holding the excavator, and not crumbling down and thus not supporting the weight of the excavator. Rolling the ex isn't something you want on your "to do" list.

Once you get started, you will likely figure out the method that works best for you and hope you enjoy the seat time. It looks like fun. Not sure if the excavator will be large enough to empty into a dump truck, but may a dump trailer.

A pic of the area to be landscaped would help a lot. And some info about the soil you are going to dig up as well.

 

[captaincrab55]

Start slow and at the point you marked. Decide if you want to stay on the edge and go the full 6' down before backing up to take the next bite. That should keep you "on the level".
Or if you want take less than the full depth and back up the full width, but know this will entail getting on the slope with the excavator to take the next course off.
You will need to access the risk of the edge holding the excavator, and not crumbling down and thus not supporting the weight of the excavator. Rolling the ex isn't something you want on your "to do" list.

Once you get started, you will likely figure out the method that works best for you and hope you enjoy the seat time. It looks like fun. Not sure if the excavator will be large enough to empty into a dump truck, but may a dump trailer.

A pic of the area to be landscaped would help a lot. And some info about the soil you are going to dig up as well.

beenthere, Good Advice.... One needs to get rid of the spoil sooner than latter... One should dig a shelf till they get to Grade as beenthere touched on...

Do you have an Instrument (not musical / lol) to aid in obtaining Grade ????

 

[Craig Clayton]

I dug up part of my driveway 2 years ago to loose some stone rubble in the bottom of it. I used a 6' 6" BH on a Kubota of which I own the whole lot. I trenched 40' in length by 5' wide at 3' in depth. The gravel was piled 18" deep on oneside of the drive and the subsoil was kept in the pit so as not to spoil the gravel or lawn. The stone rubble was moved by being pulled and dumped in the pit, the subsoil was moved from one side of the pit to the other side . I did not want the subsoil out as it would have been as mess.
The hardest part was putting the gravel back in the hole with a BH. It was very easy to dig it out. You need to get a bucket load and put it straight in a dump trailer/or thing to haul it to the new location, handle it only once.
Craig Clayton

 

[Craig Clayton]

I went to do some dishes left in the sink, it helps with domestic bliss, started doing some mental math. Wiped my hands off,and picked up the plastic brain.
A triangle area 1/2 base x height
24 div 2 =12
12x6x200 = 14400
14400 div 27= 533.3 yd.
15,000 was stated correct before.
Assume 2.5 cu ft bucket
14400 div 2.5 = 5760 scoops.

You could be there for awhile.
I only dug up 600 cu ft or 22 cu yds.
Craig Clayton

 

[HiTechTed]

First let me thank you guys for your input, I appreciate the tips and welcome any more that you have. I realize my situation isn't ideal but it's kind of what I have to work with. Thankfully it's not a critical job and I don't have to be perfect!

The soil is fairly sandy, with no clay or any rocks to speak of. When I get a chance to go back there I'll take a picture or two of what I'm talking about.

Captain asked if I had any way of measuring the grade...I currently don't but it will probably be 3 months before I can do anything due to the weather, so between now and then I'll try to come up with a solution. Right now I'm just planning projects, trying to get myself lined up for things to come.