Media

News

03.12.2008

ONKALO personnel shaft to be extended down to 290 metres

The personnel shaft of ONKALO is being extended from 180 metres down to 290 metres. The exhaust air shaft of ONKALO was earlier in the autumn raise-bored to this depth, and according to plans, the inlet air shaft will also be drilled down to 290 metres next year.

The extension of the personnel shaft was started by controlled drilling of a 30-cm pilot hole from the -180 m level in order to produce an as vertical hole as possible down to -290. According to Supervisor Kimmo Lehtola, the orientation accuracy achieved with the pilot hole was excellent, with a maximum deviation of 15 cm.


The backreaming of the shaft with a 4,5-metre reamer bit from the –290 level to the –180 level started toward the end of November at an average rate of 0.5 metres per hour and is expected to be completed in mid-December.


During the construction of ONKALO the personnel shaft is used as an exhaust air and smoke vent shaft. The use of the shaft as an actual personnel shaft starts at the end of the construction project, when it will be equipped with a personnel lift.


The raise-boring of the inlet air shaft will be carried out next year in three campaigns. The drilling contractor is the Swedish Bergteamet company.


Return to headlines



Share article:
This website stores cookies on your computer. These cookies are used to improve our website and provide more personalised services to you.
Close

Cookies

To make this site work properly, we sometimes place small data files called cookies on your device. Most big websites do this too.

1. What are cookies?

A cookie is a small text file that a website saves on your computer or mobile device when you visit the site. It enables the website to remember your actions and preferences (such as login, language, font size and other display preferences) over a period of time, so you don’t have to keep re-entering them whenever you come back to the site or browse from one page to another.

2. How do we use cookies?

A number of our pages use cookies to remember your actions and preferences (such as login, language, font size and other display preferences.)

Also, some videos embedded in our pages use a cookie to anonymously gather statistics on how you got there and what videos you visited.

Enabling these cookies is not strictly necessary for the website to work but it will provide you with a better browsing experience. You can delete or block these cookies, but if you do that some features of this site may not work as intended.

The cookie-related information is not used to identify you personally and the pattern data is fully under our control. These cookies are not used for any purpose other than those described here.

3. How to control cookies

You can control and/or delete cookies as you wish – for details, see aboutcookies.org. You can delete all cookies that are already on your computer and you can set most browsers to prevent them from being placed. If you do this, however, you may have to manually adjust some preferences every time you visit a site and some services and functionalities may not work.

Close