- Technical implementation went very well, says Hans Dreyer, project manager in the company Boston AS and responsible for the practical work. Divers who participated in the project were able to report that masses from the drone lay out over the bottom in fine and even layers. Hydro is now awaiting a report from tests and analyzes.

The test operation will provide answers to which methods are best suited to cover the contaminated bottom in the Gunneklevfjord.

Positive Interest

Dreyer talks about positive interest from curious neighbors. Among other things, he tells of a lady who paid special attention.

- She called and told that the pipe cable we used had separated a pair of swans. So then we helped make an opening for the swan couple to find together again.

Full control

- From the control room, we have full control over the amount and weight of masses in and out, and from here we control the drone's route and laying of masses, says Hans Dreyer. We also have a full overview of printing and speed of laying. Then we manage to lay out thin layers on the bottom.

Is thin layers important?

- Yes, if the layers become too thick, we are afraid that the load will be too great and that the bottom may slip out. The bottom conditions in Gunneklev vary. We have measured the thickness and strength of the bottom, and there are slopes and slopes to take into account. In some areas, two meters of fjord bottom have been measured. When this is located on slopes, they can slide out like a "snow avalanche". We want to avoid that. With a thin layer, there is little pressure on the bottom.

The Norwegian Environment Agency close

The Norwegian Environment Agency follows closely and gained insight into the test operation on inspection together with Hydro's project manager, Thor Oscar Bolstad.

- Gunneklev will be "pure fjord" again, says Bolstad. According to the plan, the cover project will be completed by the end of 2021, possibly somewhat later if there is some of the planned backfill in Gunneklevfjorden under the auspices of Herøya Industripark AS.

By Siri Krohn-Fagervoll and Dag Jenssen