This is the 12284th most frequent Polish word.
mineralnych
"Mineralnych" means "mineral" (adjective, plural or genitive singular) in English.
Here, 'mineralnych' is an adjective describing the type of springs, indicating they are mineral in nature.
Woda mineralnych źródeł jest zdrowa.
The water of mineral springs is healthy.
In this sentence, 'mineralnych' modifies 'substancji' (substances), describing substances that are composed of minerals.
Produkty mineralnych substancji są wykorzystywane w przemysłach.
Products of mineral substances are used in industries.
Here, 'mineralnych' specifies the type of soil components, illustrating that these components are mineral in origin.