Versatile Drillrig

The production drilling process was made considerably easier in 1999, when Atlas Copco donated the use of a ROC 642 HP crawler drill, with Secoroc R32 10 ft Speedrods (male/female) and 35 mm and 48 mm bits, for the winter months of that year. The drillrig worked so well that the Crazy Horse Memorial Foundation bought it at a special price, and has been using it ever since!

At its launch in the mid-nineties, the ROC 642 HP was rated as one of the most versatile surface rigs on the market on account of its large engine, powerful drive motors, and low centre of gravity. It developed a reputation as the most economical drillrig available for hole depths up to 18 m, and diameters up to 3.5 in. It is an exceptionally manoeuvrable, medium-size machine, with good hill climbing ability. The water cooled, turbo-charged 145 HP (107 kW) Deutz diesel engine provides more than enough power for all functions, so is never over-stressed, resulting in long life, low maintenance, and clean, economical running.

The ROC 642 HP is equipped with the COP 1238 rock drill, the most popular rig mounted machine in the world, with alu­minium cylinder feed. The feed beam is lighter than steel, and infinitely more resistant to bending. The smooth and regular force output by the cylinder-actuated feed mechanism keeps the joints in the drill-string tight, and maintains the drillbit in constant contact with the rock. Standard features are double hydraulic drillsteel support, reducible percussion pressure, anti-jamming function, automatic feed control, and two speed traction motors.

The ROC 642 HP has been drilling 300-500 ft/day of 1.825 in-diameter boreholes using Secoroc bits and steel. It is the main-stay of the fleet, and has proved to be both reliable and productive, with the crew praising the reach, manoeuvrability and overall drilling rates achieved in the peg­matite granite.

The drillrig is maintained at workshops on the peak, and is expected to be available for work throughout the winter months. The wind and weather can be severe at these heights, even in summer. An adjacent mountain, which once hosted the largest mica mine in the world, just 800 ft higher than Thunderhead, is the highest peak east of the Rockies to the Swiss Alps.

Lists of words

1. pride –гордість

2. possess –володіти

3. steel drill – сталевий бур

4. gravity – сила ваги, тяжіння

5. to overstress – перенапружуватися

6. hand held machine – ручна

бурильна машина

7. mica –слюда

8. mine –рудник, шахта

9. versatile - універсальний

10. crawler drill – буровий станок

на гусеничному ходу

11. undertake – розпочати

12. foundation - фундамент

13. drive motor – приводний двигун

14. reach – радіус дії

15. bending - вигинання

16. borehole – бурова свердловина

Quarrying Across the united Kindom

Aggregate for the Cities

Large quarries are located near rail-heads in the United Kingdom so that aggregate can be shipped across the country with minimum inconve-nience. All of these operations are governed by strict environmental regulations, particularly in relation to dust and noise. Less drilling for more production is a very attractive propo-sition, and that is what Atlas Copco rigs in various guises are delivering. Owned and operated by specialist drilling contractors of long standing, the drillrigs are worked hard and moved often. Four of the largest operating companies are featured below, and all of them endorse the Atlas Copco ROC series of hydraulic rigs that are setting the pace at every quarry in which they appear.

Sleeman

From its Frome base in England's West Country, W C D Sleeman & Sons, Ltd supplies drilling and blasting services to a total of 18 quarries in Somerset and Herefordshire.

Most of this output is crushed and screened at site, and railed to London on purpose-built trains. Set up some 27 years ago with a single Atlas Copco pneumatic drillrig, Sleeman now operates a fleet of nine Atlas Copco DTH machines, compris­ing a ROC L8, three ROC L6s, and five ROC 460s. All of these machines are moved frequently between sites, because their individual productivity outstrips the capacity of any single client quarry. However, the combination of fast drilling rigs and easy movement makes perfect economic sense, and is becoming increas­ingly popular amongst contractors working small and medium-sized quarries.

Since inception, Sleeman has offered a full drilling and blasting service to its clients. The company provides the drillrigs and site personnel, and undertakes the esign and layout of the blasting grid, sur­veys the holes, carries out laser profiling of the face, and specifies the blast design.

At Moons Hill quarry, Somerset, in an extension of the main pit, the Sleeman ROC L8, equipped with a Secoroc COP 44 hammer, is employed drilling 115 mm holes on a 4.0 m x 4.0 m grid. The bench height is 10 m, and the basalt is hard and loose jointed, a situation where DTH drilling excels. Face angle is normally 15 degrees, but this may be reduced to 10 degrees in certain areas.

Explosives are delivered on an as-needed basis, to avoid the potential prob­lems associated with site magazine location and security. The lower 6 m of each prepared hole is loaded with 13 kg/m of Orica bulk emulsion and a 16L Pentolite booster primed using a Sureline non­electric detonator. The top 4 m of each hole is then stemmed using 14 mm chippings.

Every month. Sleeman brings in a 20 t excavator equipped with a hydraulic break-er to dispense with any build-up of over-size boulders.

The company provides drilling services to seven or eight other quarries in and around the Mendip Hills, the Somerset geological structure that hosts large lime-stone reserves.

Three of the Sleeman Atlas Copco ROC 460 drillrigs are also engaged in doing small jobs around the Mendips, while one ROC 460 is based at a 1 million t/y opera­tion, and the fifth ROC 460 covers quarries with a combined output of 1.4 million t/y.

Each of the ROC 460 drillrigs is pow­ered by an Atlas Copco XR compressor rated at 12-20 bar pressure.

The Sleeman ROC L6s rotate between drill & blast contracts with bench heights in the order of 14-15 m, which is close to the maximum height allowable in the United Kingdom without a full geological survey. Hole size is normally 115 mm, but some 20% are drilled at 127 mm-diameter. In the limestone rock that characterizes most of their sites, a 4.5 m x 4.5 m grid is chosen, in order to reduce fly rock and concentrate the muckpile.

Planned performance for the ROC L6 and ROC L8 machines is 1.5 m/min, and for the smaller ROC 460 is 600 mm/min.

The Secoroc Magnum premium quality drillbits are lasting a minimum of 1,000 drillmetres, and are treated as consum­ables, so regrinding is not carried out. Sleeman produces some 5.5 million t/y under drilling & blasting contracts.

Blasting Services

The first UK customer to invest in Atlas Copco's new, high-power, ROC L6H DTH crawler rig was Blasting Services Ltd of Alfreton, Derbyshire. The busy drilling and blasting contractor has expanded its fleet to four Atlas Copco rigs. Blasting Services felt the time was right for substantial investment in their fleet to meet increasing customer demand for both production, and health and safety. They see Atlas Copco as a big player, and an excellent partner intent on providing the best service support now, and in the future.

Blasting Services carries out contract drilling and production blasting in the Midlands, mainly at quarries in Derbyshire and Shropshire, and also in North Wales. These quarries produce material from a variety of hard rock types such as lime-stone, granite, and sandstone, using a drill-hole diameter range of 110 mm through to 130 mm. The average annual blasted ton-nage expected is approximately 1.75 mil-lion t/machine, which is equivalent to around 48,000 drillmetres/year/rig.

The self-contained, high-performance ROC L6H, which combines properties of the proven ROC L6 and ROC L8 rigs, features a high-delivery 850 cu ft/min (401 lit/sec) of air from the onboard 25-bar Atlas Copco compressor, for increased drilling speeds in medium-strength to softer rock formations. The rigs provide high production drilling capability in Blasting Services' bread-and-butter work for quarry blasthole drilling, and also feature the flexibility needed for develop-ment work. For example, the mast, which accommodates 5 m-long drilltubes, can be turned through 90 degrees to drill toe holes, as well as any angled holes in between. The hole inclination is controlled electronically, and instrumentation is pro­vided to check on hole depth. A dust col-lector has a retractable suction hood and pre-separator. The rig is also highly manoeuvrable, with a tramming speed of 3.4 km/h (2.1 miles/h), a grade climbing ability of 20 degrees, and a traction force of 110 kN (24,729 Ibf) from a two-speed drive. The ROC L6H is designed for drilling holes in the diameter range 92-152 mm (3%-6 in) using COP 34, 44 or 54 down-hole hammer drills. The typical maximum hole depth is 36 m (118 ft) with a drilltube handling system to hold eight tubes. The drive is provided by a water-cooled Caterpillar diesel engine.

The Blasting Services machine features a central lubrication system, which, in con­junction with a daily and weekly mainte­nance regime, will ensure reliability of operation. The operator's cab, with full ROPS and FOPS specification, is equipped with air conditioning and a heater is standard.The ROC series of drillrigs are designed with easy transportation in mind, and the dimensions are well within the European guidelines for movement by low loader, so no permits are required.

Lists of words

1. govern - керувати

2. explosion – вибух

4. planned - запланований

6. blasting - підривання

7. purpose- ціль

8. however -однак

9. services - послуги

10. transportation – транспортування

11. lubrication – мастило

12. design - проектувати

13. mainte­nance -обслуговування

14. dimension – габарит, розмір

15. approximately -приблизно

16. capability -здатність

18. movement - рух

19. pneumatic - пневматичний

20. prepared – готовий