Sully's timing tells the whole story of the region. He set up in Silverton in 1882, when that settlement looked like the future of mining in the Far West. But in 1883 prospectors pegged leases along a broken hill to the southeast, and when silver was confirmed there in 1885, fortunes and people shifted overnight. Silverton emptied; Broken Hill exploded. Sully read the signs and relocated in 1885, raising a substantial stone building with an arched, galvanised-iron roof on Argent Street while much of the town was still tents and timber. To build in solid stone, that early, was an act of faith in a place that had barely begun.

On 1 November 1886, Sully's new building took on a civic role: it became the first post office in Broken Hill. In a remote inland town cut off by hundreds of kilometres of dry country, the post office was a lifeline — the thread connecting miners and shopkeepers to family, money, news and the wider world beyond the lode. From this stone counter on Argent Street, letters went out across the colony and arrived from across the seas. Around 1900 Sully expanded, adding an adjoining building split into an office and a grocery store, the business growing with the city it had bet on. The emporium adjoins what is now the Silver City Working Men's Club on Argent Street, and the two-storey stone structure runs back to a cellar beneath its rear — substantial bones for a shop raised on a raw mining field.

Walter Sully & Co. went on to become the longest-surviving commercial business in Broken Hill — a continuity almost unheard of in a boom-and-bust mining town, where enterprises rose and fell with the price of metal. Through strikes, slumps and the slow grind of the mines, the emporium kept its doors open, supplying the everyday goods that kept a frontier city running. Its endurance is part of why the building earned a place on the New South Wales State Heritage Register in April 1999, a stone survivor from the field's very first year.

In 1998 the Broken Hill City Council bought the old emporium to give a permanent home to the Broken Hill Regional Art Gallery — and that gallery carries a distinction of its own. Founded in 1904, it is the oldest regional art gallery in New South Wales, begun with a bequest of three artworks from George McCulloch, one of the Syndicate of Seven who founded BHP and the broader Broken Hill venture. After renovations, the collection moved into the Argent Street building in October 2004. So the loop closes: a shop built by a man chasing the silver rush now displays the art of a city the silver built, in a gallery seeded by one of the founders of the mine. The stone walls that once weighed flour and sold stamps now hang paintings — still serving Broken Hill, more than 140 years on.