Treblinka I was a gravel quarry equipped with heavy machinery, essential to the production of concrete and road construction. Before the German occupation, the mega quarry was owned by the Polish industrialist Marian Łopuszyński who built a railway track connecting the mine with Małkinia–Sokołów Podlaski junction. Setting up a penal colony there was the idea of "Sturmbannführer" Ernst Gramss who first ran it as his own personal business venture in occupied Poland. The quarry became vital during the German attack on the Soviet Union, supplying gravel for the strategic road-building programme around the German–Soviet border.&lt;ref name="Kopówka/Rytel-Andrianik"&gt;&lt;/ref&gt;