Painting VK Komolova - sketch?

[гимназистка]

Dear experts, please help to determine the pattern of Basil Komolova "Pit". Cardboard or orgalit, oil. Signatures not found. Size 20 x 26 cm, year of establishment, according to the inscription on the back, 1960. Kuplena in 2008 at an auction in Florida. Three Questions:
1. This is a sketch or a finished painting?
2. Does Komolov to the "sixties" in the sense in which that term is used on the site?
3. Interested in price and investment potential. At the base of artists it is not only his wife.

Last photo - looking like that "Quarry" from the gallery Zenin, http://www.zeninagallery.ru/index.php?id=1072
Thank you very much.