Moving dirt

[Rlh constructio]

I'm starting a new job building a extension on a airport . There is around 30000 cubic yards. I own 4 dump trucks of my own and have a 220 komatsu excavator. The pit is a half mile away. My question is what's the best method to make this job successful and profitable. There is no room to get scrapers in the pit. Would it be worth my money to rent off road trucks to haul more yardage. Thanks in advance.

 

[lumberjack]

How are you handling on the fill sight? Compaction tests?

What's the terrain like between the pit and the fill?

How busy are you/is there a time frame on the contract?


Depending on those variables and the rental/operator expense of off road dumps, I would decide between on road and off road trucks. If the terrain allowed, I would hire oodles of tandems for $60/hr or semis for $80/hr including the drivers. If it's worth it, run your trucks in the circuit. You'd be looking at ~2k loads on a tandem (here), and ~1250 loads in a semi. With a good road, a 5-7 minute cycle time (hopefully), add trucks to the rotation until you've reached saturation with your excavator and roll with it. How many yards per minute can your excavator load?

 

[Rlh constructio]

The haul road is pretty ruff. The land is sandy with solid rock underneath so it doesn't drain well and it's ruff. The total job is 120days total and there's more than dirt with $750 a day damages. It's pretty hard to find trucks around here. Everyone is pretty busy. The full site has 30 feet of fill at one point. We have a d4 and a compactor running. It has no trouble staying up. When we was doing some test runs its around 25 min turn around time. Thanks for any advice

 

[lumberjack]

I'm hardly a big dirt guy, but I'm a numbers guy and on occasion I do some dirt work. 25 minutes to move a load half a mile? That's a crazy long time. I had a job in 2013 moving 1k yards of stockpiled dirt 1/3 of a mile. I loaded ~8 yards on my dump trailer with a CTL. The dump was a swamp, so we could dump 6 loads or so then move the CTL down and push the dirt out. Just moving the dirt we averaged between 6-7 minutes per cycle.

We hauled 8k yards in on that job, pushing out with the CTL and compacting with a small/tiny compactor and the CTL. Nuke testing, house pad.



Why so long for a cycle? The trucks running from the pit ~12 miles from the site (through the city) averaged ~59 minutes over several hundred loads, the drive time on Google is 24 minutes.

 

[Shimmy1]

Get that 4 busy and fix the haul road. Half mile haul, that 220 should be working his @ss off to keep up to those trucks. If not, get a bigger bucket on the hoe. You should have a 2 yd bucket, 5 dumps and see you later. You should be moving at least 3000 yds per day. You might need another roller.

 

[Rlh constructio]

We will work on the haul road this week. The pit is on the Arkansas department of corrections with a lot of turns and things to go around It's prob closer to mile haul road and there is just a lot of crap between point a to point b. I didn't know with the haul road being ruff if off roads trucks had the speed and could take the glade rock sticking out of the ground better than dump trucks.

 

[Shimmy1]

Sounds like fixing up the haul road is not an option. Like Lumberjack says, you're going to have to just add trucks, either contract trucks or ATDs, until the hoe is working steady. I still think you are going to need a couple more pieces of knockdown equipment to be efficient. Do you have 120 days to do the dirt work, or is that the timeframe for the entire job?

 

[CM1995]

An off road or arctic truck needs a smooth haul road as well in order to make production. Yeah they can take a little rougher road faster than an on-road truck but there not going to get the production on a rough haul road.

I agree with Shimmy you need to move 3K yards a day. When I am calculating on-road truck yardage I use 10 CY for tandem and 15 CY per tri of loose yards per load. So that would be 300 loads a day on a tandem or 200 tri-axle loads per day.

200 loads a day is doable with a 220 but 300 is pushing it. You are moving the same amount of yards but adding another 100 trips of trucks coming in and pulling out will add time.

The last big dirt job I was on we had a 325DL loading and 2 725 attics hauling. Total haul round trip was less than 1/4 mile. We would average 180-200 loads a day with the one hoe and two trucks but this was shot rock so it slowed down production. Used a D6N on the spreading end, since it was shot rock there was no compaction testing and didn't have to use the roller much. The fill lift was 3-4' thick, so spreading was easy.

Have you checked into the monthly rental rates for attics? They can be expensive when you add operator and fuel to the rental cost. It may be cheaper to fix the haul road and hire trucks.

A D4 will not keep up with that many loads coming in, you'll need a another dozer. Depending on the size of your roller probably another roller too. Will there be compaction testing?

That's a fair amount of dirt to haul with the equipment you have. If I were you I'd really put a pencil to this one before I submitted a bid especially due to the liquidated damages clause.

 

[Oxbow]

It seems to me that the speed in which you can lay the material down, water, and get compaction will be the aspect that will determine your production. The last airport runway dirt job that I was on had a 102% compaction standard. In order to obtain that the moisture had to be dead on, and processing/compaction time was the weak link. These are variables that are much harder to calculate than hauling production.

 

[CM1995]

Good point Oxbow, we need to know the spec's. Depending on what time of year this project rolls into, it will be too much water which is much harder to handle in the winter down here.

 

[Shimmy1]

It seems to me that the speed in which you can lay the material down, water, and get compaction will be the aspect that will determine your production. The last airport runway dirt job that I was on had a 102% compaction standard. In order to obtain that the moisture had to be dead on, and processing/compaction time was the weak link. These are variables that are much harder to calculate than hauling production.

102%?? You must have been packing gravel? No way could an engineer design 102 into a clay fill. If it got wet the swelling would be ridiculous. What was the optimum moisture? Around 10% I would guess?

 

[Oxbow]

102%?? You must have been packing gravel? No way could an engineer design 102 into a clay fill. If it got wet the swelling would be ridiculous. What was the optimum moisture? Around 10% I would guess?

Shimmy, it was material that had a lot of fine sand in it, and optimum was at 13% if I recall correctly. We could nail 98% without much difficulty, but to get over a hundred we had to rip the fill that we had put in and then add water until we could barely move around with the scrapers, then keep working it until it set up. After doing that we were consistent @ 102 to 104 %.

It took a bit for the soil tech to get it through my thick skull that compaction over 100% was even possible, and I still don't understand it completely.

Fortunately, we had compaction testing done as soon as we started the fill, so we discovered the problem before having to remove a bunch of fill.

This was a number of years ago, but I will never forget to look closely at the compaction specs anytime an airport job comes up as they are much more stringent than highway specs.

 

[ShaneK]

I'm starting a new job building a extension on a airport . There is around 30000 cubic yards. I own 4 dump trucks of my own and have a 220 komatsu excavator. The pit is a half mile away. My question is what's the best method to make this job successful and profitable. There is no room to get scrapers in the pit. Would it be worth my money to rent off road trucks to haul more yardage. Thanks in advance.

Sounds like a bit of a pickle, but with the chance of very good profitability if you pick the right equipment. Are you sure there is no way to get a scraper in there? If you'd attach a scraper pan to one of your ADT's, perhaps that would get you the flexibility to manouever through the pit, and then get out to book it down the haul road and back!

 

[buckfever]

I will start this post by saying I hate using on-road trucks for moving dirt off-road. By the sound of your haul road a ADT is only gonna shave a few minutes off your haul time but using a 35 or 40 ton truck will get your yards moved per hour up a good bit. The only problem with using big trucks is they dump big piles of dirt and I can tell you my d5m struggles to handle them. Your d4 would have you dirt bound pretty quick and a lot of waiting for the roller to finish.

 

[lumberjack]

Does he have enough excavator to support two 30 or 40T artics?

 

[buckfever]

If my math is right that would be one truck every 30 mins. Can't see that being a problem unless he's in a lot of rock.

 

[lumberjack]

I would think improving the haul road so the trucks can get their speed up over the 1/2-1 mile. Loading artics that have double the payload of the gross weight of the machine loading them seems ill paired... but I'm certainly out of my depth in such things, and tandems/semis are cheap to hire here (flat rate, no rent, fuel, and operator).

 

[Rlh constructio]

We finally got to rolling good this week. We have 4 dump trucks and 1 end dump. We have about a 15 min turn around time but we are putting in some big lifts on the dump end and it's slowing us down trying to get around everything. It's going pretty good. My pit hit solid sandstone at about 15 feet so I can't go as deep as I was wanting . Thanks for all the advice

 

[Shimmy1]

We finally got to rolling good this week. We have 4 dump trucks and 1 end dump. We have about a 15 min turn around time but we are putting in some big lifts on the dump end and it's slowing us down trying to get around everything. It's going pretty good. My pit hit solid sandstone at about 15 feet so I can't go as deep as I was wanting . Thanks for all the advice

Sounds good. You should be at or above 3000 yds a day so long as your boys aren't 9-5ers.

 

[Phil O'Malley]

I agree with buckfever. Using on-road trucks for off-road duties is the worst.