His name is on the family gravestone, but he was buried at Maytown, Queensland, during the gold rush there. Died of pneumonia. The local chemist probably saw to the burial there, and promptly wrote home to his sorrowing parents. Cairns Historical Society helped me here.
Probably not married.
See books on the Palmer River Goldrush: "The River of Gold" by Hector Holthouse.
A report of the Cairns Historical Association mentions a Mr. Mackay who drove a dray with a team of six horses during the Palmer River Gold Rush. Among the ten or fifteen thousand prospectors and followers there must have been more than one Mackay. Yet this could have been Andrew! And who suggested to Andrew that he should join in the Gold Rush? One of his two uncles in Australia whom I have not traced?
Addendum No. 5
Letter from S. E. Stephens, 5, Corkill Street, Freshwater, Queensland, Australia. 4870. Dated 15th December 1970.
re. Andrew Mackay
As far as I have been able to ascertain, there were only two newspapers in Maytown, "The Golden Age", published in 1876 only, and "The Palmer Chronicle" published from 1876 to 1880, and in 1886 to 1889. No copies of either have survived.
Maytown itself no longer exists, and no buildings are left in the town. The cemetery still exists and contains a number of graves marked by headstones, and many without stones.
The entry in the Death Register for Palmer is as follows:
Entry No. 433.
On 22nd March 1878 at Gregory's, Palmer Goldfield, Andrew McKay, a miner aged 32 years. Died of pneumonia after seven days illness, the medical attendant being J. Marshall who last saw him on the day he died.
The names of parents are stated as unknown, and marital status also unknown. It is stated that he was born in Scotland but there is no information as to the length of his residence in Australia. He was buried on the 23rd March 1878 at Maytown by George Corrie. The death was registered by J. Marshall, chemist of Maytown, and recorded by the district registrar, P.F. Sellheim, who was also the Gold Commissioner and Magistrate at Maytown.
(Gregory's may have been a small boarding house, but more probably was a miners' camp near Maytown.)
(I expect George Corrie was the person who informed Andrew's parents of the date and time of their son's death.)
Mr. Stephens is the President of the Historical Society of Cairns, and also Honorary Curator of History at the James Cook Museum at Cooktown.