Inverness-shire (which back then included places now in Argyll).
Not strictly true. With a couple of very minor exceptions anywhere that was in Inverness-shire/County of Inverness is still in Inverness-shire/County of Inverness, and anywhere that was in Argyll(shire)/County of Argyll is still in Argyllshire/County of Argyll.
This map shows the pre-1975 boundaries of the Counties
https://en.wikipedia.org/wiki/List_of_local_government_areas_in_Scotland_(1930%E2%80%931975)
However in 1975 (not quite 50 years ago) the Powers That Be thought fit to reorganise the structure of local government, and to revise the boundaries. The new Districts were given different names - parts of Inverness-shire went into Argyll and Bute; Skye and Lochalsh; Lochaber; Inverness; and Badenoch and Strathspey, all of which were part of Highland Region.
This map shows the boundaries of the short-lived Districts
https://en.wikipedia.org/wiki/Local_government_areas_of_Scotland_(1975%E2%80%931996)
Then in 1995 They decided to do away with the two-tier system of local government, and abolished the Districts in Highland Region that had existed for only 20 years. So mainland Inverness-shire and Skye were amalgamated with Nairnshire, Caithness, Sutherland and mainland Ross and Cromarty to form the present Highland.
You will see if you compare the two maps that the north-western part of Argyllshire/County of Argyll became part of the new Lochaber District in 1975, and of Highland in 1996. However
it did not become part of Inverness-shire/County of Inverness. The rest of Argyllshire/County of Argyll became part of
Argyll and Bute District.
All of which is very annoying if you are interested in events that took place, and records that were created, before 1975.
Fortunately only two mainland parishes straddle the Argyllshire/Inverness-shire county boundary, namely Ardnamurchan and Kilmallie. Kilmallie is usually listed as part of Inverness-shire, as are the Small Isles, and Ardnamurchan as part of Argyllshire. So the only Argyllshire parish that you need to consider as a possible birthplace of your Donald is Ardnamurchan.
There was an earlier reorganisation of boundaries around 1890, which tinkered with the county and parish boundaries and affected some parishes that straddled county boundaries. The only areas transferred from Argyllshire to Inverness-shire were parts of the Small Isles (Eigg, Rum, Muck and Canna) and part of the parish of Kilmallie. There's a detailed list of what areas were were transferred where at
https://www.genuki.org.uk/big/sct/shennan/inverness. It mentions a short list of places transferred from Argyllshire to Inverness-shire, but no places were transferred from Inverness-shire to Argyllshire.
I hadn't heard of mining in the Inverness area.
There is no coal in Inverness-shire, but there are or were minor deposits of minerals all over the Highlands. The most frequent is ironstone, but without reading the relevant sections of all the New Statistical Account parish articles at
https://stataccscot.edina.ac.uk/static/statacc/dist/county/Inverness I can't think of an obvious way to find out where mining was active in the 1840s.
I haven't been able to find a family that meets all those details in either birth records or Censuses, and several families with one detail different. I have been using Ancestry.com, Family Search and Scotland's People.
See
https://www.rootschat.com/forum/index.php?topic=714261.0