Old English min "mine, my," (pronoun and adjective), from Proto-Germanic *minaz (source also of Old Frisian, Old Saxon Old High German min, Middle Dutch, Dutch mijn, German mein, Old Norse minn, Gothic meins "my, mine"), from the base of me.
As an adjective, "belonging to me," preceding its noun (which may be omitted), it was superseded from 13c. by my when the noun is expressed. As a noun, "my people, my family," from Old English. In this heart of mine, no fault of mine, etc., the form is a double genitive.
"explosive device," by 1866 in reference to submarine weapons (at first not distinguished from torpedoes), from mine (v.2). By 1890 as "land-mine, explosive device placed on the ground (or just under it) as a weapon."
c. 1300, minen, "to dig a tunnel under fortifications to overthrow them," from mine (n.1) or from Old French miner "to dig, mine; exterminate," from the French noun. From mid-14c. as "to dig in the earth" (in order to obtain minerals, treasure, etc.). Figurative meaning "ruin or destroy by slow or secret methods" is from mid-14c. Transitive sense of "to extract by mining" is from late 14c. For the sense of "to lay (explosive) mines," see mine (v.2). Related: Mined; mining.
"pit or tunnel made in the earth for the purpose of obtaining metals and minerals," c. 1300, from Old French mine "vein, lode; tunnel, shaft; mineral ore; mine" (for coal, tin, etc,) and from Medieval Latin mina, minera "ore," a word of uncertain origin, probably from a Celtic source (compare Welsh mwyn, Irish mein "ore, mine"), from Old Celtic *meini-. Italy and Greece were relatively poor in minerals, thus they did not contribute a word for this to English, but there was extensive mining from an early date in Celtic lands (Cornwall, etc.).
From c. 1400 in the military sense of "a tunnel under fortifications to overthrow them" (for further development of this sense see mine (n.2)).
Old English lond, land, "ground, soil," also "definite portion of the earth's surface, home region of a person or a people, territory marked by political boundaries," from Proto-Germanic *landja- (source also of Old Norse, Old Frisian Dutch, Gothic land, German Land), perhaps from PIE *lendh- (2) "land, open land, heath" (source also of Old Irish land, Middle Welsh llan "an open space," Welsh llan "enclosure, church," Breton lann "heath," source of French lande; Old Church Slavonic ledina "waste land, heath," Czech lada "fallow land"). But Boutkan finds no IE etymology and suspects a substratum word in Germanic,
Etymological evidence and Gothic use indicates the original Germanic sense was "a definite portion of the earth's surface owned by an individual or home of a nation." The meaning was early extended to "solid surface of the earth," a sense which once had belonged to the ancestor of Modern English earth (n.). Original senses of land in English now tend to go with country. To take the lay of the land is a nautical expression. In the American English exclamation land's sakes (1846) land is a euphemism for Lord.