This nondescript building is the office of two dwarves, Gravlet Truther and Kip Trathis, who maintain and operate a mining and excavation enterprise out of it. The pair are notoriously spendthrift with their money, and refuse to pay anyone else to do work that they can't do themselves.
The company usually has a variety of operations in process at any given time, and currently are working on reopening the Zolurket Mines (despite the rumors of undead there), and excavating the region around the Crouching Jackal. They claim to have come across an ancient scroll depicting other structures around the statue, and think that their excavation efforts will reveal other lost structures buried beneath the sand.
The truth behind the Zolurket Mines operation is that it is, in fact, haunted by the two dwarves' dead business partner, Tibbler Rocksledge, abandoned decades ago to a mummy attack when the trio was first exploring the mines. The ghost of Tibbler haunts the mines in anticipation of the return of Truther and Trathis, who have returned several times searching for rich platinum deposits buried there.
The current mining operation is their most ambitious to date: they've employed diggers to tunnel through the rock around their ghostly foe, but the work goes slowly and the two dwarves are growing more and more frustrated. They are ready to hire a group of specialize ghost hunters to take out Tibbler permanently, despite the extra costs and hassle involved in employing adventurers. What they haven't realized is that the only way to permanently destroy the ghost is to satisfy its need to bring the pair to justice.