okay, let me ask you a few questions... what did you use to dig your test holes? i work in excavation and i can tell you that as a general rule of thumb when starting a project you want to bring out the biggest machine that you can get for your digging. the only reason i ask is because if you dug your test holes with an auger or a small backhoe you might...i emphasize might....be encountering rock that a larger machine might not have problems with.

while im not familiar with your local geology i can tell you that around here (northern california) i typically encounter lave cap and granite. lava cap is soft enough that a big excavator or a large bulldozer with rippers,say a d-9 or so can usually do a lot of damage without having to get out a breaker. on the other hand with granite, we always have to use a breaker. some of the blue granite that we have locally can test at upwards of 12,000 psi compressive strength, to put it in perspective, your average run of the mill 5 sac concrete for house slabs is probably about 2500 psi compresive strength. the point is though, bigger equipment may get the job done. you may want to re-consider the size of the equipment that you are planning to use.

also how deep do you want to go??? if your hitting rock at 6 feet and you only want to go to 10 feet, a big excavator with a breaker could get the job done in a reasonable time frame.

basically with rock, there are four possible solutions, only one of them is cheap:

1- dont dig

2- try to use a bigger equipment

3- a hydraulic breaker

4- blasting with dynamite, or use expansive grout or equivilant.

check with your local builing authority or local contractor on the use of explosives in your area. blasting can get expensive real fast. you have to core drill out holes for it, set the explosives and re-cover, usually around here we have to get engineers involved and it gets pricy real quick. your better option, is to use dexpan or something similar. if you have access to a large roto-hammer or a core drill you can buy dexpan with no liscence and it will break rocks to pieces overnight while you sleep. do a google search for dexpan non explosive demolition. this stuff works great, you might need a lot of it though.

good luck - justin