Nothing for magnetofloatation, but ore dressing finally turned up a shitty little article.
From the en.wikipedia.org
After 1850 the small and scattered stamp mills and ore washeries were replaced by central ore dressing plants.
From the en.wikipedia.org
In 1905 the most modern ore dressing plant in Germany went into operation in Clausthal using the gravity dressing process.
From the en.wikipedia.org
The separation of mineral from gangue is known as mineral processing, mineral dressing or ore dressing and it is a necessary and often significant aspect of mining.
From the en.wikipedia.org
The need for this process, which was known as dressing the ore, increased as the poorer sources of lode tin were exploited.