Forget Creatine and Andro - that's for serious weight lifters who are seeking to gain more muscle mass and will continue seeking more gains.
Yes Sports figures use these, they also follow a pretty strict weight lifting regiment designed to increase muscle mass and to increase endurance. However for them it is a "work out" for you its a job - meaning that sooner or later you will plateau - meaning reach your peak efficiency with no more additions to your "workout" to cause the muscles to seek to grow stronger/more massive. Also, they only work out for a couple hours, you are seeking to go marathon, 10 hours a day. Far cry from what a work out is.
What you may desire to do is address snacking during the day along with lots of water. AND.... Well I will cover all the points:
In a few weeks your muscles will adjust to the heavy work load, what may lag here is your energy level - The body gets all of its energy from sugars. A snickers may sound great and it will give you a burst of energy, however it is not well suited for long term energy.
Carbs are important and in a job like this you should eat more carbs. Carbs are converted into sugars which are released onto the blood stream slowly and evenly. Sugar is energy, thus if you need more energy for the long haul carbs are more important than a snickers which will give you a sudden short boost but leave you lagging in the end.
You may want to use protein shakes during the first month of this hard labor - this will feed your muscles needs and give them the stuff they need to adapt rapidly (meaning gain more muscle mass) I would not take it more than a month in this case, the mass you are lifting is pretty constant and you will plateau in a month's time.
However for every rule of thumb in weight lifting there is an acception, it is possible that your muscles will continue to grow for up to 6 months - you can pretty much tell if a month from now you are still making gains, if so, continue using the protien shakes until you have ceased getting harder and more mass.
Now the scales will be liars, you may initially lose mass (fatty tissue) before you start gaining.
Unless you intent to start a work out program too (Which I doubt given the hours and hard labor here) Creatine, Andro and other "weight lifter's" supplements mayn't be a wise choice. Also they are pretty expensive.
On protein shakes: Whey (which comes from animal products) is absorbed and used more efficiently than Soy (which comes from vegetable products).
I would recommend taking a daily vitamin/mineral supplement and up your vitamin C intake during this first month. 1 gram (1,000 mg) of Vitamin C during this first month taken in the after noon - assuming you have taken your multi vitamin in the morning. Why? Because starting this job is going to be very stressful for the body which will lower its immunity to the common cold and other things. Vitamin C will help you stay healthy.
Liquids: You may be tempted to drink a lot of stuff, stick to the cool clean water, 6- 8 glasses a day - Slack your thirst on water - All of that lifting will cause you to perspire. Things like Soda, Juices and even Gatorade have added stuff to them which will cause to to dehydrate faster than water. Your muscles are going to need as much water as possible in order to gain mass and strength.
BEFORE you start working, Stretch - Seriously, warm up before you start the job, stretch and after you finish moving all that material don't just sit down, cool off slowly and continue slow movement of the muscles you have used - this will prevent them from stiffening and getting as sore.
http://k2.kirtland.cc.mi.us/~balbachl/stretch.htm or search the subject for demonstrations. Stretching will be key to your ability to do this job and will reduce the chances for injury.
Muscles get sore due to the small fact that the act of exercising them causes them to shred and release acids. If a person immediately sits down instead of continue to keep the blood flowing, the acids and dead tissues will not be carried away - causing pain and stiffness. This is another reason why I say drink lots of water - This will help your body flush out those toxins, dead tissues, acids, etc.
Breathe: Take a deep breath before you lift, let the air out as you lift - This will give your body oxygen, between lifts take a deep breath or two - Oxygen will be consumed by the body rapidly under this kind of labor. Taking deep breathes will not only help you maintain your energy level but will go a long way toward removing those toxins your muscles are releasing.
And Lastly, lift with your legs, not with your back. And keep those abs tight when lifting. Most back injuries come because a person does not tighten and hold their abs, the abs are part of the support structure of your back and torso. Letting them be slack means you will put more stress on the back muscles.
I think that just about covers it.
Cheers
David