What is it worth?

[sireath]

Not sure how it is done in your area. Over here. They want us to on set out just before they start boring and that means in your case it will be 34 different trips.

Boreholes are over here are not that accurate within 20-30mm is good enough.

But just to know GPS i doubt you are able to get mm accuracy with them, at the most 15-20mm accuracy but that is with static sessions.

[john-giles]

34 trips. I didn’t consider that. That would really increase the costs.

I can set up the control with GPS and then go TS from there. I’m only guessing at accuracy. They haven’t gotten back to me on that yet. First question I asked was ‘how accurate do you need them.” I never thought about asking how many I could lay out at a time. I’ll have to ask them that tomorrow. thanks.

[sireath]

It depends on how many rigs they have available and how close are the bore holes are to each other. If they are too close, they are unable to put the rig there.

[paul-in-pa]

I would quote laying out 34 holes in so many hours/days @ $xxxx

To restake it is a minimum of x hours to restake 1 or 5? holes @ $xxx

For a day of staking 10? holes @ $xxx.

Guide them to an understanding that how they do their job affects their cost of you doing your job.

34 bore holes in 1-2 acres sounds like the bores are for construction of piers. Piers laid out in a grid may interfere with any number of bore holes, so they need to let you know their proposed drilling and construction sequence and how many drill rigs they propose to use. Bore holes can vary greatly in time to complete, especially if the are required to go to varying depth bedrock or must be at a minimum depth, come rock or not.

For instance 3 bore holes for a 3 pier bridge support, may have to have all concrete completed to the bridge span height before the next set of holes are started.

Ask more questions, and don’t forget to ask about payment timing.

Paul in PA

[john-giles]

It’s for a pond being built in a wildlife management area. I should have noted that at the beginning. Anyone else work on one of these? It’s well within my abilities I’m just not sure how things will progress. I can lose my butt on some boundary work before I’ll lose my butt on government work. 😀

[spledeus]

One man operation?
You should charge the Robot and the GPS as a second person. Then you will pay for the toy.
I have had great luck setting a stake at a point. Then set 3 offsets and locate them. Inverse and then pull distances and average to set the pin on the first stake. Then locate the pin and pull the offsets. Usually this falls well within 0.05′.

[ridge]

If they are geotechnical bore holes they don’t need to be that tight. I’d suspect someone that doesn’t understand the needed specs did them, you might quiz them or suggest that, yeah you can do them real tight but it will cost more and whether they really need that. I designed earthen dams for 5 years for the Soil Conservation Service. We would drill the center line at 100 foot intervals. I’d have been fine at a 1 foot tolerance and being that far apart I think that they could all be staked ahead of time. You just need to find out what they really need, the spacing and at what tolerance.

[a-harris]

I’ve made bore locations before and did them at the same time.
They were for possible landfill locations and all the bore locations took a couple of days to set on their grid and we ran 3D traverse with a TS thru the woods on all of them.

It took the bore company much longer to do their part.

[jimcox]

How do the points need to be marked?

A gps point marked with spray paint does not take long.

Setting a peg takes longer.

And they might want a label on a stake…

[bill93]

John Giles, post: 345709, member: 57 wrote: within a few hundredths of the coordinates given to me.

Is the absolute location critical, or only spacing within the pattern? If absolute position is important, you need to be very careful of the datum and how they arrived at their coordinates. NAD83(which?)

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[david-livingstone]

I’ve set a lot of bore stakes at a nearby landfill. Assuming its in an open sky area, its something that would take me 4 hours or less alone. This includes the time it takes me to set up my GPS and take it down.

On this particular site I already have control and a job set up in the computer. They usually give me a cad drawing or some other method to quickly get points in the data collector also. If you have to mess with control and keying coordinates in, that could take longer than setting the stakes.

[gmpls]

I’ve done alot of boring stakeouts and I’ve also worked around Geotech rigs alot. The drillers don’t often drill exactly where the so point is. We usually set pk’s or spikes or paint if it was on dry pavement. If the borings are close together and evenly spaced you could set points at every other one and just a paint spot in between (make sure you store elevations for all points though). I would say 34 borings with a gps would take a day or 2 at most, depending on site conditions.

[sonofa]

The main thing to consider is how many return trips your client will require to complete their design. Depending on the project, the design team may need to fine tune things based upon geotech results or obstructions, which usually means a call back out to shoot/locate additional holes.