So a little over a year ago (best i remember)
 i had a pond in my yard and the plastic liner had broken.
 (its about 12ft by 8ft wide 4 or 5ft deep.)
 
 It was a mosquito nursery, and was a big problem.
 I finally cleaned it out to a bare dirt floor.
 
 a buddy of mine makes and sells organic fruit juices
 and he has 5 gallon buckets of mango, banana, citrus , beet, and other peels.
 i dumped about 40 of the 5gal buckets in the hole.
 i added 2 large bags of sawdust
 about 400lb of coffee groundes
 5 or 6 bags of grass clippings
 various leaves,  yard waste etc...
 
 unfortunately, i have a bad back, and mixing it was a problem.
 and.... mistake #1 was putting the peels (very wet, lots of rotting juices) in first.
 i did add a few small cardboard boxes at bottom, but, sawdust would have been better
 i just didnt have any at the time. i got it a week later.
 then i added grounds, grass, leaves, more grounds, cardboard, grounds, sawdust etc...
 till it was full.
 
 i put a couple of long 2x6 planks down to walk on it.
 and now i finally took them up and tested my weight.
 in most areas, it is fairly solid.
 in 1 spot i sunk about a foot down.
 
 i dug up a shovel full, and i was surprised to find dirt... ?#@!?>
 it was a very dark, very rich "mud"
 (it did rain recently, cool temps, and no sun to dry thing out)
 
 it is still about 4 to 6 inches low, so , i am still adding leaves, grounds etc... to it.
 it had sunk a little, but , not much.
 
 There are drier spots where the top couple of inches is excellent 
compost.
 but, that very well could be coffee grounds and grass clippings added 6 months ago.
 
 it seems the worms are churning things up also... which must be how i got soil in the mix.
 
 i get 100lb of coffee grounds every week or so from starbucks.
 i have used them in experiments of sorts.
 also, i can get 7ft tall bags of sawdust from a cabinet maker.
 this is like having finely ground wood chips.
 
 i once made a pile of semi-dried grounds, dry oak leaves and semi-dry grass clippings
 the oak leaves were small, and the grass clippings had been run-over twice.
 this produced the best compost i had ever seen,
 i could have sifted it though a pasta colander.
 i added a little sand and used it as seed-starting mix (great stuff)
 
 another one was sawdust, grass clippings and grounds.
 it made excellent worm food.
 and i use it as a mulch... it has to be used as a thin layer and mixed well
 as the grounds can form an impenetrable barrier to water.
 mixed well, with less % of grounds, can fix the issue also.
 
 i used this mix also to put UNDER cardboard to keep weeds down around fruit trees.
 the worms came up and went to town.
 the cardboard kept it moist and protected.
 i do wish i would have added some coarse sand, as it gets thick and sticky without much air.
 
 
 Brad