I guess that’s an imperial measurement? In metric, baby meerkats weigh 25-35 g [1] and are about 6-8 cm long [2, 3]. Let’s say they’re roughly a cylinder 1.5x7 cm, so 12.3 cm3 or about 137 g of gold.

So they either mean there’s as much gold as a baby meerkat weighs, 30 g give or take, or the equivalent baby meerkat volume, which would be 137 g-ish.

I’m no expert on meerkats or sewers so I can’t help you there 🤷‍♂️