The document discusses rock excavatability, influenced by rock strength and layer thickness, outlining various excavation methods such as digging, breaking, and blasting. It details methods for assessing rock types, machinery outputs, and the impact of explosives on vibration levels during blasting. Additionally, it highlights operational procedures for drilling, blasting, and hauling, ensuring efficiency and safety standards are met throughout the excavation process.

1. Rock Excavatability
The excavatability of rock depends mainly on the rock strength & layer thickness (bed spacings)
The diagram shows excavation methods given the bed spacings and rock strength descriptions.
Excavation methods considered are Digging, Rock breaking and Blasting.
Bed Spacings (layer thickness) Rock Strength ( Field Estimation)
Very Small - up to 60mm Weak :- Gravel size lumps can be broken by heavy hand pressure.
Small - 60mm > 200mm Moderately Weak :- Only edges can be broken by heavy hand pressure.
Medium - 200mm > 600mm Moderate Strong :- Can be broken by hammer blows when held in hand.
Large - 600mm > 1m Strong :- Can be broken by hammer blows when on a solid surface.
Very Large - 1m > 4m Very strong :- Rock chipped by hammer blow.
Extremely Strong :- Rock rings on hammer blows, Needs sledge to break.
HARD DIG ROCKBREAKER
EASY DIG
Very Small -
Small - BLAST
Medium -
Large -
Extremely Strong
Very Large - Very Strong
Strong
Moderate Strong
Moderately Weak
Weak
Excavatability 3D Diagram for Rock with a Free Face
Schedule of Rockbreaking Outputs Rock Description :-
Strong with Large bed spacings
Plant
Excavator 25 tonne with Rockbreaker 2 tonne. 5 m3 / hour 3 m3 / hour
Excavator 40 tonne with Rockbreaker 3.5 tonne. 8 m3 / hour 4 m3 / hour
Excavator 70 tonne with Rockbreaker 6 tonne. 14 m3 / hour 7 m3 / hour
Rock Hammer's Preformance.
Rockbreaking - 5 Tips on correct use to achieve efficiency.
1 Place the Hammer at 90* to the workface.
2 Use the excavator boom to press the breaker firmly against the rock.
3
4 Stop the breaker quickly, as idle strokes, after the rock breaks, will damage the breaker.
5 Do not strike in one spot for more than 15 seconds, as the chisel would overheat.
Soils - Strength Scale Term Field Identification
& Classification Very Soft Extrudes between fingers when squeezed in hand.
Soft Moulded by light finger pressure.
Firm Can be moulded by strong finger pressure.
Stiff Can be indented by thumb.
Very Stiff Can be indented by thumb nail .
Do not let the chisel move outwards from the breaker when it penetrates the rock. Feed the breaker
all the time with the excavator boom.
Trenches
Rock breakers can be judged by their output power rating which is their single blow impact energy multiplied by the
frequency i.e. number of blows per minute. The impact energy breaks the rock and the frequency determines the
penetration rate into the rock.
Open Areas
The Association of Equipment Manufacturers, "AEM", formed the Mounted Breaker Manufacturers Bureau "MBMB", test
and issue results known as the AEM-MBMB rating system for breakers.

2. Drill, Blast & Crush rock Motorway Cut - Sequence
Step 1 Strip Topsoil & Overburden Step 2 Drill Blast-holes Step 3 Charge & Stem Holes Step 4 Exclusion Zone - 150 m radius
Resources: Excavator 45 tonne & Dumpers 40 tonne Resources :- Drill Rig & Shot Firer & Helper Resources :- Shot Firer, Helper & Loader
Duration :-
Step 5 Blast & set up Seismographs Step 6 Secondary Breaking of Rock Step 7 Load & Crush Step 8 Load & Haul away from Crusher
Resources :- Explosives & Detonators Resources :- Wheeled Loader & Dumpers
Ratio of Explosives to Rock = 0.3 kgs per m3 Qty & Outputs :- 1,100 m3 or 2,500 tonnes per day Qty & Outputs :- Load 240 tonne or 100 m3 / hour
Jaw Crusher produces 150 mm down fill material.
Typical Charging ( Explosive & Detonators )
Shock wave tube Depth Spacing Burden
Depths
Distance Weight (kgs) - M.I.C. 1 m 5 m 1 m 3 m 3 m
Explosives per delay. 2 m 2.7 m minimum depth of Stemming
50 m 5.71 kgs 3 m to plug hole
90 m 18.50 kgs 4 m
200 m 91.40 kgs 5 m Formation
350 m 280.00 kgs 6 m 1 m depth Sub drilling
Effects of Peak Partical Velocity (PPV) values Explosive with Detonator
Note: The PPV is the strength of the vibration Distance to nearest Structure = 90 m
PPV Value Maximun Charge per delay = 18.5 kgs
mm / second
0.5 Perceptible motion level to people Grid ( Spacings by Burden) = 3 m x 3 m
10 Usual limit set on contracts. Volumn of rock per hole = 54 m3
51 Safe Limit by US Bureau of Mines Ratio; Explosives to Rock = 0.3 kgs per m3
127 50% Probability of Minor Plaster damage Charge required = 16.2 kgs
193 50% Probability of Major Plaster damage
Comment / Effect
Resources :- Excavator 45 tonne with 4 tonne rockbreaker
Note :- Typically 30 % of blasted rock to be broken to fit
into the Crusher opening.
Quantities = 2,600 m3 of blasted rock & 0.78 tonne of
Explosives
Quantity / Distance Relationship
for a P.P.V. of 10mm / second
as determined by Trial Blast on site
Depth
6 m
Total
Sub
Drilling
Typical wheeled articulated loader weighs 19 tonne and has a
bucket capacity of 4 m3.
Qty & Outputs :- Excavator 45 tonne will dig & load 190 m3 /
hour
Blasts designed to ensure vibration at nearest structure is below the limit set of 10 mm / second (P.P.V.) and to fragment the
rock so it can be crushed with minimum secondary breaking. Note; Maximum Instantaneaous Charge M.I.C. is the amount of
explosive in kilograms which is detonated at a given moment in time, this determins the vibration.
Sub-drilling is drilling below the required depth to allow for poor
fragmentation at the bottom of blast-hole.
Blast Design Points
• Carry out condition surveys on nearby buildings to record
existing cracks.
• Purpose of Blast; to fragment the rock so it can be loaded into a
crusher with the minimum amount of secondary breaking.
• Design blast to minimise ground vibration & fly-rock.
Down-the-Hole hammer drilling is a percussive-drilling method,
where the percussion ( hitting / hammer action) happens behind the bit
down in the hole and the rotating mechanism is located on the drill rig.
Qty & Outputs :- 30% x 2,600 m3 divided by 30 m3 / hour
=> 26 hours
Qty & Outputs :- 30 holes per shift 110 mm dia x 6m deep Stemming is material placed in the top of a blast hole, overlying
the explosive, which prevents all the explosive energy blowing
out of the top of the hole.
i.e. Place explosive and detonator in hole & fill with 20 mm
aggregates as plug.
Resources :- Jaw Crusher on tracks & Excavator 35 tonne
Drilling Pattern
Crusher Capacity:
300 tonnes per hour,
1100 mm x 700mm opening
150 m
150 m
Burden
Spacings

3. Underwater Drill, Blast & Dredge Rock
Step 1 Equip Spud Barge Step 2 Install Casing to Rock Step 3 Drill 65 mm dia blast-holes Step 4 Install Ducts & Remove Casing
Resources :- Crawler Crane 30 tonne capacity
Top of duct to be above high tide level.
Step 5 Charge Holes from Work Boat Step 6 Move Barge away from Blast Step 7 Blast Rock Step 8 Dredge Rock & Load Hopper Barge
Qty & Outputs :- 3 hours to load 50 m3 barge
Ratio of Explosives to Rock = 1.4 kgs per m3 of rock. Duration :-
Typical Charging ( Explosive & Detonators ) Notes
Shock wave tube
Plastic Tube 50 mm dia Depth Spacing Burden
Distance Weight (kgs )- M.I.C. 2 m 1.5 m 1.2 m 1.2 m
Explosives per delay.
50 m 5.71 kgs Water
90 m 18.50 kgs
200 m 91.40 kgs
350 m 280.00 kgs
Effects of Peak Partical Velocity (PPV) values 1 m 0.7 m depth of Stemming
to plug hole
2 m Formation
PPV Value
mm / second 3.5 m 1.5 m depth Sub drilling
0.5 Perceptible motion level to people
10 Usual limit set on contracts. Explosive with Detonator
51 Safe Limit by US Bureau of Mines
127 50% Probability of Minor Plaster damage Grid ( Spacings by Burden) = 1.2 m x 1.2 m
193 50% Probability of Major Plaster damage Ratio; Explosives to Rock = 1.4 kgs per m3
Comment / Effect
• Nitroglycerine-type explosive along with non-electric
detonators will be used to maximise the use of delay blasting
techniques to fragment the rock.
• To avoid fly rock the holes will have 700mm depth of
stemming and blasting will be during daily high tide. Stemming
is material placed in the top of a blast hole, overlying the
explosive, which prevents all the explosive energy blowing out
of the top of the hole.
• Blasts to be designed to ensure vibration level at nearest
structure is below the limit set of 10 mm per second P.P.V.
and to fragment the rock so it can be dredged and loaded into
a hopper barge.
Casing used to exclude foreign material and for locating
duct in hole
Resources :- Spud Barge with Excavator 70 tonne &
Hopper Barge
Resources :- Drilling Rig with Drifter aka Tophammer.
Resources :- Tug Boat
Fix depth gauges to existing harbour wall showing the
drill depth below tide level.
Drifter aka Tophammer drilling is a percussive-drilling method,
where both the percussion ( hitting action) & rotating mechanism is
located on the drill rig's boom.
• Trial Blasts carried out to establish the Maximum
Instantaneaous Charge M.I.C. is the amount of explosive in
kilograms which is detonated at a given moment in time.
Blasts are made up of multiple holes with a delay of a few
milliseconds between each one. In this way, the amount of
energy entering the rock at a single moment is reduced, which
lowers the vibration level.
Note: The PPV is the strength of the vibration
Resources: Barge with Spuds, Crawler Crane 30 tonne,
Drilling Rig with drifter hammer and purpose built platform on
front for working over water, Tug & Work Boat, Store,
Canteen, Toilet & Mooring Winches
Quantity / Distance Relationship
for a P.P.V. of 10mm / second
as determined by Trial Blast on site
Set up seismographs at the nearest buildings to monitor
vibration level of blast.
3.5 m
Total
Sub
Drilling
i.e. Place Explosive and Detonator in hole & fill with 12 mm
chips as plug ( Stemming ). Detonating cord connects the
detonators to shore for firing.
Detonators typically have time delays of 25 milliseconds
intervals.
Drilling Pattern - 1.2 m spacings by 1.2 m burden
subdrill by 1.5 m below formation
• Rock Description ; Strong quartzite with medium spaced
discontinuities and highly fractured zones
Drilling Pattern
Depth
Qty & Outputs :-
Qty & Outputs :-
Ducting is used to load holes with Explosives, Detonator &
Stemming
Spacings
Burden
Rotating
mechanism &
Tophammer
Drill String

4. C:UsersDavid MoloneyDocuments1 Book Construction Planning1 Haulage & Fill
Fill
Cut
Typical Cut to Fill Situation
davmol .
Step 1 Dig, swing 90* & Load Step 2 Haulage by Dumpers 40 tonne.
Excavator 45 tonne with bucket - heaped capacity = 2.3 m3
Dumper 40 tonne with tailgate - heaped capacity = 22.7 m3
1 km 9 minutes
Output ;- Excavator 45 tonne - 6 minutes to load 40 tonne Dumper Output ;- See below 7 km 33 minutes
12 km 53 minutes
Step 3 Tip & Spread Step 4 Compaction & Shape side slope
Output ;- Dozer D65 - capacity 40 loads per hour Output ;- Roller Single Drum 16 tonne
i.e. spread load of 17.5 m3 every 1½ minutes Average 800 m3 per hour
Schedule of Dumper's Haulage Outputs
Haul Distance Haulage Cycle Loads per hour Volume per hour
Taken as volume for Sub soil before bulking.
1 km 9 minutes 6.67 loads 17.5 m3 117 m3
7 km 33 minutes 1.82 loads 17.5 m3 32 m3
12 km 53 minutes 1.13 loads 17.5 m3 20 m3
Haulage Cycle Times ( load / haul / tip / return )
Haul Distance Time to travel Time to return
Average speed 30 km / hour
= 1 km every 2 minute
1 km 4 minutes 2 minutes 1 minutes 2 minutes 9 minutes
7 km 4 minutes 14 minutes 1 minutes 14 minutes 33 minutes
12 km 4 minutes 24 minutes 1 minutes 24 minutes 53 minutes
Schedule of Excavator's Outputs
Time to Load Dumpers per Hour
to dig, swing 90* & load 40 tonne
25 tonne 1 m3 30 seconds 2 m3 120 m3 10 minutes 6 nr
35 tonne 1.2 m3 30 seconds 2.4 m3 144 m3 8 minutes 7.5 nr
45 tonne 1.6 m3 30 seconds 3.2 m3 192 m3 6.2 minutes 9.6 nr
70 tonne 3 m3 30 seconds 6 m3 360 m3 4 minutes 15 nr
Granular 10%
Sub soil 30%
Topsoil 40%
Weak Rock 30%
Notes: Hard Rock 50%
An Excavator with a 1.2 m3 bucket digs only 0.84 m3 of subsoil before bulking.
Productivity
Decide on a job efficiency % value to take account of weather, breakdowns, disruptions, queuing, resources
mismatch, site conditions etc .
Bulking Factor
( Bulk Qty ) 40 tonne
Dig, Load, Cart, Tip, Spread & Compact Fill.
per Hour Dumper
Time queue &
load
see below
Tip Cycle Time
Capacity of
Dumper
CapacityCapacity
capacity per Minute
Allow for increase in the volume of material during excavation due to
bulking. ( Increase in volume when material is loosened )
A Dumper 40 tonne with side boards and tailgate has a capacity of
22.7 m3, carries only 17.5 m3 of subsoil before bulking.
( Heaped )
Excavator
Size
Cycle TimeBucket