Drilling Patterns for Vertical drill/split Sites

Drilling Patterns are as versatile as the users or the drill operators.

  --- An example of Shaft Sinking ----

There are many type of shafts, from narrow as 2~3 meter  to rather wide  as over  10 meter wide.  The drill pattern cannot be the same.

In a drill plan we recommend following basic procedures;
1. Make central part holes closer to each hole ( 200~250mm space) or larger so that the central bore(s) can be used as free face. Central part holes are used as "free-face-holes".
2. Make boundary holes closer  to side by side.
 These boundary holes need be drilled consecutively as the bottom  ground is lowering.
3. Use some protective stuff in the drilled holes.

Drill Plan- Central hole is large, used as a free face

Narrow Shaft Drilling -Picture from N.Y Manhattan Rock site

If a large hole is not possible , you need to use small holes closer to each other.
Spacing of 200mm will be enough to break a hard rock. These holes need to be broken prior to other holes. Then the central removed space is used as "Free Face"
Above photo and the below photo is from New York contractor, Independent Equipment Corp which has been using HRD-tech.com piston splitters. ( See more at www.independentequipmentcorp.com) 

New York area has many shaft works because of bottom rock terrain. Hwacheon Piston Splitter has been used  for the rcok demolition tools mostly manual types.

 The boundary line holes need be drilled prior to other drilling. Central holes need be used as free face. Cracking direction ( piston expanding direction) need free face always.

 See below general principle of Rock Cracking .

There are requirements for the mechanization of work for larger sites. You may use 

 small size excavators for mounting( inserting the cylinders) and unloading the cylinders

 when cylinder is heavy over 35kgs.

 From our experiences, shaft work is  not a problem to use manual cylinders. You will be able to discern the best method  as you get more and more experience.

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( A case for removing ground rocks for making pond).

Following pictures are from one of our customers who are using our rock splitters for removing soft rocks from the ground rocks.  This area will be a pond  of  30 x 25 ( ft)
on plane surface.

Removing rocks from a pond site by using a rock drill, piston rock splitter and an excavator- New Boston, NH,USA

As the rocks are rather soft type, piston splitter size used is 80mm with 11 pistons.  They make hole size of 89mm (3, 1/2 inch) . They use plastic caps for protecting the holes from any debris or sand fill.

You will be able to see the boundary line drilling closer to each other roughly 20~25cm distant from each.

The splitters are in the holes. The power pack is in  a case. Hydraulic power is transmitted to each splitter through the high pressure hoses and low pressure hoses.

As the rocks are fractured, mucks are removed away from the "pond ' site

   If any reader needs any more information, feel free to ask to the blogger. You will be able to get answers from this one USA customer.              

    Feel free to share your experiences with others. The blogger will be glad to share your experience with the readers.

Making a drilling plan is possible only with experienced contractor. You need experiences with rocks' type,quality, required work procedure, worker's experience etc.

Required drill plan for Vertical splitting is different from that for Horizontal splitting. Usually horizontal splitting takes longer spacing between holes than vertical splitting.

A rule of thumb is that you make a test drill plan of 500mm distance between holes.
Then you need to make holes and test-break them with splitters. After several test-break, you will be able to understand the general drill plan.