Although I think the best way to fulfil the requirements of the POD is to make the maximum possible use of the reserves of natural petroleum that Austria, Germany and the Netherlands had, there is one way to increase Germany's coal production between 1933 and 1939 that addresses the problems that you have highlighted.To increase German coal production you need more manpower, specifically the kind of physically fit men the army also wants. On top of that as coal mining is hard physical labour you need to feed those miners a lot of calories, which means more demands on an agricultural system that is already failing to keep up with the needs of the German population and is also facing a manpower crunch, not to mention shortages of fertilizer and animal feed. In the end you can't square the circle of Nazi ideology and a working economy. Practically unlimited military spending at the expense of civilian production and exports is going to lead to disaster for an economy that needs large inputs of imported materials to function.
That is a Treaty of Versailles that does not divide Silesia between Germany and Poland.
IIRC Silesia produced 25% of Germany's coal before World War One and most of the coal producing areas were given to Poland.
Polish Silesia had a population of 1.3 million according to the Polish 1931 Census.
However, that would be a "much bigger butterfly" for Poland between the world wars than it would have been for Germany.