When noting the Market Vectors Gold Miners ETF (NYSEArca: GDX) and the Market Vectors Junior Gold Miners ETF (NYSEArca: GDXJ) are up an average of 24% over just the past month, forecasting another substantial move for these and rival ETFs appears tricky.

Then again, GDX and GDXJ are ETFs that are prone to big moves in short time frames. Add to that, gold market fundamentals appear supportive of more upside for miners. Bullion’s technical situation is compelling as well with some technical analysts saying the SPDR Gold Shares (NYSEArca: GLD) is breaking out to the upside. [Positive Signs for Gold ETFs]

As for the miners, the group’s improving ratio against the S&P 500 is an encouraging sign for ETFs like GDX.

A major shift in the Gold Bugs/SPY ratio could be taking place! The Gold Bugs/SPY ratio has fallen on hard times as stocks have outperformed the Gold bugs index over the past few years by a wide margin, pushing this index down a ton,” according to Chris Kimble of Kimble Charting Solutions.

The Gold Bugs Index ratio against the S&P currently resides at its highest levels in several months and could be poised to recapture the highs seen early in the first quarter when miners ETFs were market leaders. [Gold Miners ETFs Near Another Rally]

Kimble notes a significant change of trend could be afoot.

“Are we now witnessing a major trend change? Could be!!! The ratio may have created a double bottom this year at and over the past few weeks its attempting to break out of its steep falling channel,” he said.

There is more evidence some traders and investors are betting on another big move for gold miners ETFs. In just the past week, GDX, the largest miners ETF, has pulled in $110 million in new assets.