4. DESCRIPTION OF THE ROAD CONSTRUCTION EQUIPMENT

Regardless of the type of construction equipment used in a particular project, road construction itself remains a difficult, often hazardous operation in mountainous terrain that can inflict scars on the landscape as well as substantial damage on the forest ecosystem. In order to carry out construction operations efficiently and safely, as well as in an environmentally sound way the following should be considered:

· appropriate size and power configuration of construction equipment, adjusted to the actual needs of the construction technique applied and with respect to terrain conditions;

· appropriate equipment with respect to technical and safety standards, as well as ergonomic principles and requirements;

· only adequate trained, skilled and experienced machine operators should be employed for road construction in sensitive forest ecosystems and difficult terrain;

· well planned road design followed by fitting the road to the natural terrain as closely as possible to facilitate road construction without major problems for operators and machines;

· clear instruction to and close supervision of machine operators by the forest engineer responsible for road planning and construction.

Following these principles, the road construction equipment stated below was used for the environmentally sound forest road construction technique as described in the previous chapter at the study sites.

Table 8. Hydraulic excavators used at study sites

At study site 2 a more powerful type of excavator had been used in order to avoid the need of rock blasting. Special attention should be paid to the fact that the use of more powerful excavators might easily mislead the operator to increase subgrade width and close and more frequent supervision may be required.

Table 9. Hydraulic hammers adjusted to type of excavator

*) without adaption

The appropriate type of hammer can be selected out of a hammer series with operating weights ranging from 150 to 3500 kg for all types of carrier units ranging from 1.5 to 80 tonnes (WIMMER, 1996). The type of hydraulic hammers used are distinguished by a newly designed impact technique which guarantees high impact energy with low back thrust.

The design of the hammer enables it to be exactly positioned by the operator as the housing does not have any protruding parts (see Photo 17). This new generation of hydraulic hammers provides a better working environment for the operator because of the sound proofing and vibration damper systems, the latter also reduces the impact to the excavator's boom.

Table 10. Hydraulic drilling equipment used at the study site

*) without adaption

The hydraulic drilling unit AB3000T used at the study sites enables vertical as well as horizontal drilling by the operator as the drilling unit has 360° unlimited rotation and a swivel axis turnable by 95° (WIMMER, 1996). A no load stroke as well as an automatic antibloc system facilitates drilling in geological difficult terrain. Furthermore, the drilling unit is equipped with a radio remote control system to ensure the operator always has the optimal view to control the drilling unit. The drilling unit has its own generator so that no additional electrical installations at the excavator are necessary.

It should be noted that although road construction is machine-intensive, labour remains the most critical element for achieving the goals of environmentally sound road construction practices. Only if workers are competent in their skills, and motivated to work properly and efficiently can they be expected to contribute effectively to these goals (Dykstra and Heinrich, 1996).