Is the mining sector successful at this point in time?
The mining sector has always been subject to up and down economic success due mainly to the volatility of metal/commodity prices.
The mining sector has typically gone through "boom and bust" cycles that depend on commodity prices. For example, gold mines flourish when the price is high (say around $1000/oz), but when the price drops significantly (to say half this amount) many gold operations will shut down for awhile or permanently. Commodity prices are dependant on the demand for that particular mined commodity.
Right now in North America, the coal mining sector is becoming uneconomic as many governments are phasing out coal use for power generation, due to concerns over climate change. Similarly, uranium mining seems to be in trouble as many governments are no longer building nuclear reactors due to safety concerns.
Over the past 10-15 years or so, base metal mining (iron, copper, zinc, lead) was quite strong due primarily to the demand for these commodities from China. In more recent years, the Chinese economy is not growing as fast as it used to and so the demand and price for these metals has dropped or become more variable.
At an individual career choice level, there are many jobs for geologists, engineers, and business people in mining, but the job security aspect can be a bit risky.