It turned out to be not as poor as I anticipated, even though it’s ultimately flawed. Roger Moore ("Slade") portrays the manager of a massive gold mine, and he finds himself in a difficult position between protecting his employees and meeting the owners’ selfish requirements. A scheme orchestrated by Sir John Gielgud ("Farrell"), along with the dissatisfied son-in-law of the mine's owner ("Manfred"), Bradford Dillman, is made worse because "Slater" is having an affair with "Terry" (Susannah York), who also happens to be Dillman’s wife. The romantic elements are a bit corny, but there's some excellent cinematography that conveys the immense size of these mining operations. The writing, combined with Gielgud’s commanding performance and Milland’s spirited portrayal of mine owner "Hirschfeld," manages to draw you into this narrative about greed and power, particularly as it progresses. Moore has charisma; he earned his salary, and while it's certainly not a masterpiece, the film does provide a fairly enjoyable adventure story.

Source on TMDB