Expanding Road Construction site with D&S technology

Recently the blogger visited a rock work site in the siuthern peninsula, Korea.
They were using all kinds of equipments( excavator, rock drill rig, a hydraulic rock splitter of 4  cylinders). The road was narrow and expansion was planned by local authority.
The construction company attempted to use D&B( blasting) method. But the neighboring residents protested against this blasting and the company had to use hydraulic demolition method.
               

       

Drilling was made with spacing of 60cm,  vertically.

 They are using hand-held splitters of  4  x 95mm cylinders.

 A series of rock splitting equipments are engaged.  An excavator, a crawler rock drill rig, and a set of 4 splitters manual type .

Special remarks:

This kind of work site has very low efficiency in rock splitting because of bottle neck in drilling .  Each rock hole of 1000mm deep drilling  takes average 2minutes. It means  4 holes take time of 8 minutes in drilling.

Rock splitting ( or fracturing) takes 2~3 minutes average per cycle with 4 splitters.

An excavator is used  for a short while for mucking the rubble.

In other words, splitters and excavator is not fully utilized because of rock drilling time.

We recommend 3 rock drill rigs and 2 Splitter sets of 6 splitters ( manual type) or a set of 4 splitters of 6 splitters( machine -mounted) and an excavator.

Which set of Rock Splitter fits my Job Site?

Every Set is Built for its Maximum Utilization.

A hydraulic rock splitter is very convenient and useful tool for breaking any kind of rock.

Unlike blasting method, there is no legal restriction in its use. It is safe. It is environment -friendly.  It is simple to use- by just plug in to an electrical cord.

There are several kinds of set are available on the market. Whcih set should I choose?

Let's examine which sets are available on the market.

85mm diameter hand-held  set of 6 splitters

                               

** Hand-held splitter set: 

   One power pack + multiple cylinders( usually 4~6) + hoses + case.

 A set consists of one power pack in common regardless of varying splitters.

 Hand-held splitters must not be too heavy to move around. So the maximum weight of

 splitter  is limited to under 35~36kgs.  However if the length is too short, work performance is reduced also.  HRD-tech.com has been recommending maximum weight to 30kgs or under and the length to under 800mm. 

For example, 80mm diameter , 689mm long splitter  weighs  28.5kgs  and  80mm dia. 730mm long splitter weighs 30.8kgs.

In case of 85mm diameter , 660mm long spliter weighs 30.6kgs  and  720mm long splitter weighs 33.3kgs.

In case of 90mm diameter, 650mm long splitter weighs 32.7 kgs.

In case of 95mm diameter, 608mm long splitter weighs 34.7kgs.

HRD-tech.com has been offering the splitters with maximum expanding force with light weight at similar cost raqnge regardless of length or number of pistons.

Our client may purchase  4 splitters of 80mm diameter splitters or 95mm diameter splitters 4 splitters at similar cost from HRD-tech.com.  Some customer requests special  size like 135mm diameter with 2 pistons splitter. We supply 135mm diameter or 182mm diameter splitter at similar range even that size is specially order-made.
The customer must be able to consider drilling holes size first . If the hole size is 90mm , the suitable splitter diameter is 80mm. If the drill hole size is 200mm~203mm, we build the splitter diameter of 182~185mm .

***Machine-held splitters :

As the hand-held splitter is limited in its splitting capacity, machine -held splitters have been tried by professional contractors. HRD-tech.com has been the major developer and designer of these splitters too.

The diameter of splitter is usually limited to 95mm, 100mm, 110mm, 135mm and 182mm.
Please refer to above table 100,105,110mm diameter sizes.
The length is longer than manual types. It is varying from 800mm to 1,500mm.
Our recommended length is either 1000mm or 1,500mm .

Machine held splitters have more distant spacing than manual types, starting from 700mm upto 1,500mm.

**  Which set fits my job site?

In the starting stage, we recommend to use hand-held splitters . However if the work site is large and demanding fast work, machine-held splitters are recommended.

Selection of splitters is determined by drill rig's capacity very much. If your drill rig can make holes of 90mm, you need to choose 80mm diameter splitter.( 10mm difference)
If you drill holes of 115mm or 127mm, your splitter needs be 100mm dia or 110mm dia cylinders. The number of piston in each cylinder is decided by its total length or weight.

When you have one set of 6 hand-held splitters, you can keep pace with 2 or 3 drill rigs' drilling.

In other words, bottle-neck is the hole-drilling . In the beginning, if you keep 2 or 3 drill rigs, then you need a set of 6 splitter sets.

Selection of drill bit ( size) should precede selection of splitter's size( diameter and length) reflecting the drill rig's capacity and power of it.

How to make order details for a new Rock Splitter?

Which size Splitters Fit my Job Site?

It is not easy to fix the set for a new businessman though the amount of splitter is not so great.
Following things should be considered :

1. Rock volume to remove.
2. Time frame for the removal project.
3. Required equipments beside the splitters set.
4. Required manpower by quality or experiences.
5. Total available finance.


Once you have above figures in details, still you need to know how much volume of work you can proceed every day or every week . 

 D&S tech regards the drilling capacity the most important factor.

With a hand-held splitters set:

As known before, hydraulic splitting follows after the holes are ready. The spacing is a decisive factor in work rate ( or speed).  This spacing is a mix of three factors: splitter force,  rock's strength, and drill rig's capacity.
When the spacing is made too near  from optimal distance, total number of holes are too many and time-taking delay occurs. On the contrary to this, if the spacing is too far from optimal, the splitter may take too long time to split.  So the spacing has to be decided by an experienced drill rig operator who knows drill capacity as well as rocks quality and splitter's quality.

We suggest a spacing of 500mm in the beginning as a rule of thumb. This spacing should be modified carefully after some experiences to less or longer distance.  There are very hard stone like quartz which are hard to drill a few inches per minute. With this kind of ultra hard rocks, you have to adjust the hole distance
to 20~30cm .  There are also soft rocks .If you can drill holes of 1200mm within 20~30 seconds, you may make spacing distance of 1,000mm from the beginning.  It is difficult to generalize of standardize this spacing matter in a simple figure. Instead, you have to touch and experience with your body.

We recommend one of followings:

1. When your work load is small or  once for all with enough time frame, 
   we recommend the  small diameter splitters of 80mm or 85mm. 
    These splitters have 10,11,12 pistons on each cylinder. Total length of splitter is upto 800mm.
   HRD-tech.com keep 10pistons splitters in stock usually for prompt delivery.
  The drill rig makes holes of 89mm or 95mm . Small size holes take less time than large ones.

2. When your work load is large and repeated continuously for more than a year job,
   we recommend the large diameter splitters of 95mm ( or 90mm) 
  Drill holes are 105mm or 100mm . The drill rig is usually larger ones too than small hole drill rigs.
   With this size, hand-held splitters are shorter than smaller ones because of weight limit.
  Usual splitter's length is between 600mm to 700mm.
  
 Large diameter pistons produce stronger forces than smaller diameter pistons. Eventually, the large diameter splitters are good for fracturing the hard rocks too.

3.  When you work with very very hard rock, we recommend to use larger size splitters of one or two pistons      
       ( 135mm dia splitters with 2 pistons)                 ( 182mm diameter splitter with one pistons )
 For example, 135mm diameter splitter is built with two pistons in a cylinder.  182mm diameter spliter has one piston in a cylinder. For a manual handling, the weight needs to be limited under 40kgs.
 This large diameter splitter is good for fracturing the hard rock with large spacing of more than 1000mm.

Hand-held 95mm dia splitters in holes of 105mm

 

   With spacing of 600mm between hard rocks, the 95mm splitters of 700mm long  work fine in granite sites.

Vertically drilled holes of 105mm  are spaced 600mm between holes.

                                

With machine-held Splitters;

Machine -mounted or machine held splitters are specially designed and offered.  Some of them are shown as below;

 1. Excavator-mounted splitters of 150mm diameter with 8 pistons

  

 2. Other sizes : 

    100mm splitters of 800mm long with 10 pistons.

    135mm splitters of 900mm long with 7 pistons.

    As drill rigs are limited in maximum hole sizes, either  115mm holes or 127mm holes are recommended.

   The length of splitters is not limited in weight nor depth.  It is recommended to fit the fastest rate of drill rig  in deciding the length of the splitters.

  Special grip system togetherwith coupler device is provided according to request. We also accept your suggestion in building the splitter structure.

  We are using our expertise in building cylinder and pistons which will last for the most durable time.

             

A representative  splitter  85mm diameter 11pistons, 780mm long.

A Suggestive Drill pattern for Quarry sites

An inquiry from a Quarry site :

   Can we apply  hydraulic splitting to replace explosives?
   How many sets of hydraulic splitters are in need?

Whenever we get a question on our hydraulic rock splitting performance, we feel sorry that we are unable to reply with adequate answers. The performance of rock splitting is decided by drilling performance on the site!

If you keep only one drill rig whcih can make 50 holes per hour, you can split that number 50 holes  with a set of 6 cylinders in an hour. Splitting requires pre-drilled holes always.

If you keep two drill rigs which can make holes of 100 per hour, you can split  100 holes per hour with the same set fo 6 splitters too.

If you keep 3 drill rigs which can make holes of 150 per hour, can a set of 6 cylinders split those 150 holes?. It depends on several factors.( spacing, rock strength, splitter's power). you need to study its details before you say yes, or no.

The blogger  had received above inquiry and tried to understand the quarry site situation. The inquirer sent some more information as follows:

The quarry site had been using explosives for a long time. But now they had to consider alternative rock breaking than explosives. The quarry is surrounded by rock wall of 15meter high. Every hour the quarry needs production of  100 cube meter rocks before crush.


A basic concept in drilling rock holes:

Hard rock requires more stress than soft rock.  Distant spacing requires more stress than close spacing.  Rock splitters have differing expanding stress from others depending on the splitter sizes. There are various kinds of rocks to break. Where can we start ?

(1)Make "initial spacing" as 500mm . This spacing means from center of hole to next center of hole. You can adjust the distance after some experience with the rock site.

(2) Drill holes as deep as 1,000mm or so.
With a manual type splitter, you need rock holes depth of 1000mm or over.  So the rock holes need be drilled 1000mm or longer  deep. With a mechanical type splitter, the length of cylinder differs variously from 300mm upto 1,300mm or so.

(3) Calculate each cycle time of 6 cylinders  as 4 minutes .  A manual type set splits the  6 holes within 3~5 minutes per cycle. This cycle includes time of insertion and taking out of the cylinder to next holes.   Just apply 4minutes as a cycle time.
 This cycle time depends on the size of cylinders, kind of type( mechanical or manual). and  the rock's characteristics . A manual type is breaking rock as deep as 700mm .
Let's assume we shall take manual type sets of splitters .

Understanding above basics, we need calculate volume of rocks per each cycle splitting.
 6 x 0.5m x0.5m x0.7m = 1.05 (cube meter). / 4 minutes.( with manual type splitters)
Therefore, each hour can split the rocks of  15.75 cube meters.( = 15 x 1.05 )
Splitting 100 cube meter rock requires 6.4 times( sets) of  15.75( 100 / 15.75= 6.4) .

Some other considerations:

Assumed set of splitter  is either 85 mm diameter 10 piston cylinder  set or 95mm diameter 7 pistons cylinder set. When we use a mechanical type splitter, rock holes, piston cylinder diameters and length of the cylinder can be varying.

Assumed rock strength is between 50~100MPa in compressive strength. According to the differing strength of the rock the distance can be adjusted.

Assumed length of splitter is 700mm . If the length differs, the performance will vary.
Assumed strength of the power pack is 1,200 kgf/cm2.  If you want to use higher hydraulic pressure, the spacing may  vary too.

Assumed splitter set is manual type. If you use mechanical type cylinder, the performance can be more efficient.

For example,  a mechanical type cylinder of 100mm diameter has 1000mm length.
It requires spacing of 600mm between holes. This spacing reflects the spacing for the very hard rock.
Each cycle this set produces 2.16 cube meters. Each cycle takes 5 minutes.  4 sets of mechanical type cylinders can produce 100 cube meter rocks.

 6 x 0.6 x0.6 x 1.0   = 2.16 cube meter/  5 minutes. ; one cycle .
 Per hour, 12 cycles are possible.  This leads to  25.92 cube meters/ hour  ( = 12 x 2.16 )
In order to break 100 cube meter rocks,  4sets of mechanical type cylinders ( 6 x  100 mm diameter 10 pistons) are required.

In other  case, a mechanical type cylinder of diameter 100mm, 1,500mm long   can be built for more performance. It weighs around 92kgs per each.  As the splitter has long cylinder, it can break more rocks at a time.
It requires basic spacing of  600mm( very hard rock), 800mm( hard rock) and 1,000mm ( medium hard rock),
and 1,200mm ( soft rock).

Assuming that the rock is very hard rock,  6 splitters can break the rocks of  38 cube meter rock per hour.

6x 0.6 x0.6 x1.5  = 3.24 cube meter /  5minutes: one cycle.     12 cycles are possible per hour.
This results in 38 cube meters volume of rock ( = 12 x 3.24 ). In order to break 100 cube meter rocks, you will need  3 sets of  6 splitters ( 100mm diameter ,1,500mm long ) .

Assuming the rock is soft type rock,  6 splitters can break rocks of  150 cube meter.

6 x 1.2 x1.2 x1.5  = 12.96 cube meter,  / 5minutes; one cycle.  12 cycles are possible per hour.
12 x 12.96 = 155.52 cube meter.    Only one set can break rocks of 155 cube per hour.

Above suggestion is based on very conservative position.  Actual splitting time can be shorter.  Spacing can be  varying to a certain degree.  The final performance is calculated after analyzing the rocks strength and texture or location. Usually several  test breaking decides the optimal spacing.