Off the top of my head, I'd guess that in November 1927 Guinea Gold (No Liability), who had been using former CAB DH37 G-AUAA since earlier that year to service the New Guinea goldfields from Lae, transformed into Guinea Airways.
In the 1930s Guinea Airways became one of the largest air transport operators in the world, carrying more freight by air than the rest of the world's airlines put together. Among other cargoes, throughout the 1930s eight 3,000 ton gold dredges were flown from Lae, on the New Guinea north coast, to Bulolo in the highlands in one of the first major airlift operations. Since there were no roads, every piece of the dredge had to be designed to be air-transportable.
The all-metal Junkers G31go was the mainstay of the Guinea Airways fleet of cargo-lifters from May 1931, a total of four of these aircraft being used. Three (VH-UOU c/n 3011, VH-UOV c/n 3012, VH-URQ c/n 3000) were owned by Bulolo Gold Dredging Co. and operated on their behalf by Guinea Airways, whilst the fourth, VH-UOW c/n 3010, was owned by Guinea. These aircraft were built from the outset as freighters, with portholes instead of windows and a removable loading hatch over the forward fuselage. They were powered by three 500hp Pratt & Whitney Hornets (except VH-URQ which had 525hp engines).
The photo shows the Guinea Airways-owned VH-UOW. This aircraft was registered new to Guinea Airways on 10 June 1931 and served for a decade until impressed by the RAAF on 30 January 1942 as A44-1. The aircraft survived a Japanese air raid on Bulolo on 21 January 1942 which destroyed its three sister-ships as it was flying at the time. It was later evacuated to the Australian mainland and served on heavy transport duties until suffering an engine failure on takeoff at RAAF Laverton, Vic, on 31 October 1942 and crashing irreparably into the Minister of Air's car.
At Lae a steam crane was used for loading the Junkers G31s. Although there were roads in the highlands, there was no road into the highlands from the coast so even cars, such as the Austin 7 in the photo above, had to be flown in. This was by no means the smallest car to travel by air! The rail line ran from the loading area at the Lae aerodrome to the pier so cargoes could be moved easily to the aerodrome once unloaded from their ships.
