Kind sir,

You could contact Boart Longyear or many other firms that do core drilling your part of the world.

You should also investigate:

World Drilling Magazine

National Driller magazine

Geodrilling magazine

Tunneling and Trenchless Construction magazine

You should also check your local phone book for drilling contractors as it will probably be the fastest way to find a contractor to do your job.

I asm curious as to whether you are familiar with core drilling and its requirements?

Is the area in question barren with limestone at its exposed points or is preparation necessary to do core drilling?

Is there adequate water for drilling, core washing and cleaning machinery?

Is adequate manual labor present for the job?

You will require many hands to load and store core boxes and create core logs even before you have the samples tested.

How much coring sample testing are you willing to do?

You have to decide if you are going to test through the entire drillng program for all the samples as limestone quality will vary due to its sedimentary nature and other factors inherent in the stone itself.

You have neglected or not desired to tell us if the limestone is to be used for agricultural quicklime, roadbed, cement or block stone use for building construction and this is a big factor in you question simply because the monetary values differ for the three types of uses of the stone and the quality needed is different.

Is diesel fuel or gasoline available at the job site or will it have to be brought in by bowser/tanker?

How many feet of coring samples are you expecting to drill at your location? I know that here in the united states they typically charge $65.00 USD

per foot even for the small jobs.

Also related to you question is the simple fact of how big you want your core sample diameter to be simply because the larger a core diameter sample the more expensive it is and the need for larger drilling equipment.

There are lot of portable core drills that can be moved by helicopter or small trucks and or portaged by humans.

JKS Winkie makes small core drills for exploration and they are very economical with a small core size of one inch and they are capable of drilling several hundred feet so it might be worth your while to buy a small core drill and tooling to do the work with your own crew and send the samples out to be tested. The magazines I mentioned above also advertise core drill manufacturers.

It all depends on how much funding you have as the purchase of a very small core drill and tooling can be returned many times in benefits by identifying orebody location and depth along with eliminating the need to hire a contractor if you wanted to do it with your organisation as it only requires one man to operate the small core drills after a period of training by the manufacturer.

You have nor mentioned the known size and depth of the potential orebody and whether it is accessable as this is also a huge part of the question.

You need to decide how many feet of coring you wish to do per hole to proof out the ore body/seam of limestone and map out a coordinate map to do the drilling in a given area or a grid of drilling points and maintain a core log while doing this to verify all results in a given area and identify seam depth.

The other option is drilling blind to see what is below your feet using a small portable core drill with drag bits and water examing/testing the cuttings as you drill this is a very inexpensive way to do this as you are not required to remove the drill string unless you need to change the drag bit if it is worn out.

The other factor is water as you will need water to do the drilling and flushing of the cuttings to the surface and cool the core bits and to allow for core barrel extraction.

And last but not least you need to decide how long a core sample you wish to take at one time as retrieving core sample requires you to remove the drill string every time to remove the core barrel unless you use the wire line core drilling method

which allows you to pull a continuos sample provided it is nor badly broken rock.

This is a not so simple answer to your question unfortunately as you have asked a question with no easy answers and given us little information as the forum is really not meant for this as you have placed a football on a soccer pitch and not kicked to give it a direction or a goal. ■