A lot of athletes talk about “going for the gold.’’ Thomas Mashaba actually does.

The 30-year-old IBO featherweight champion from South Africa will make his American debut Friday night against Cristobal Cruz in the main event of ESPN2’s Friday Night Fights, thereby taking a small step toward living out his dream. But while his dream of one day boxing in Las Vegas is alive, so too is his need for a day job to supplement his meager earnings. And so, day after long day, Thomas Mashaba goes for the gold, quite literally.

When not in training, Mashaba works thousands of feet underground in a mine near his hometown of Carltonville, which sits in the heart of the richest gold field in South Africa. Nearly half of all the gold deposits left in the world are in South Africa and there are seven gold mines around Carltonville, which lies less than 50 miles west of Johannesburg.

That includes the deepest gold mine in the world, which spirals over 4200 meters (or nearly three miles) beneath the earth. To come from such a place is to understand that you are probably consigned to a life underground unless you can fight your way to something else, which is exactly what Thomas Mashaba decided to do.

“My aim from the beginning was to fight in Las Vegas,’’ Mashaba said this week as he rode in a van from Boston on his way to the Foxwoods Resort, where he will take the first step toward Vegas at an Indian casino in the midst of the Connecticut woods.

“My job is very difficult but it has never stopped my dream. I work collecting the gold underground, which is very dangerous. Last year, at another mine, over 3200 miners were trapped underground all night. I never think about that. I only know I have a dream of being a boxer so all the way to work that is on my mind.’’

Mashaba has a long time to think about it on most days as he and his fellow miners are taken so far beneath the earth that it is calculated in miles rather than feet. But always the dream has remained. It is the same one he first had as a boy watching American boxers like Marvin Hagler and Thomas Hearns on his television fighting in a magical place called Las Vegas.

Back then he dreamed while his father worked the mines. Today, the father is retired and it is the son who has followed him underground to help feed his own three-year-old boy, who waits for him to come back up. But unlike his father, Mashaba went into those minds carrying more than a miner’s helmet and a shovel. He went armed with a hope that one day soon he’d fight in a place where the gold sits above ground.

“Growing up I was watching Hagler, Hearns and that boy (Mike) Tyson in Las Vegas and I told everyone I’d like to fight there one day,’’ Mashaba recalled. “To come to America to fight, what can I say? I don’t know how I can put it. This is very important to me.’’

Mashaba’s manager-trainer, Eugene Khanyile, knows the importance of defeating Cruz. It will allow Mashaba to maintain control of the secondary IBO 126-pound championship he won when he upset South African fighting icon Vuyani Bungu to claim it one fight after winning the IBO’s super bantamweight (122 pound) championship one fight earlier.

To face the former IBF junior featherweight champion, who at the age of 38 was in the fourth fight of a comeback that had already made him a world champion again even if only the IBO variety this time, was considered foolhardy by many South African boxing experts. The risk was high, they insisted, and the reward unlikely because Bungu had forgotten more about fighting than Mashaba had any right to know.

The fighter knew nothing of this kind of thinking but Khanyile knew. But he also knew what all their critics did not. He knew he had a goldmine in Thomas Mashaba.

“Only he and I thought he would win,’’ Khanyile claimed. “I knew from the first time he came to the gym that Thomas had something different. I’ve trained a lot of boxers but when he hit the pads my hands were very sore. He hits very hard. In boxing that’s very important. To me, he was born to box.’’

That night Mashaba proved as much, winning a unanimous decision Khanyile says “put him on a pedestal at home.’’ It also propelled him toward three straight title defenses before promotional problems stopped his career in its tracks for a year.

After signing with South Africa’s leading promoter, Rodney Berman, they disappeared and Mashaba got back into the ring last November and produced a stunning stoppage of former IBF featherweight champion Eric Aiken on a night where he had to get up off the floor himself in the sixth round before stopping Aiken in the ninth with a punch he says he still can feel.

“When it landed I knew he would not be getting up,’’ Mashaba recalled. “I felt it in my chest.’’

Apparently Aiken felt it everywhere because when Mashaba’s left hook crashed into his face he was out before he hit the floor after having absorbed what Khanyile claims was “a terrible beating’’ in rounds 7 and 8. That the fight would end with a three-round fusillade of punches comes as no surprise to anyone who knew Mashaba because that is how he has always fought. He is a boxer who, despite his day job, really has no desire to go underground.

“When I fight I don’t leave anything behind me,’’ Mashaba said. “I’m going forward all the time. That’s me. I’m there to fight.’’

If he can continue to do that as successfully as he did against Aiken he may be able to stay above ground for a while too, whether he soon gets to Las Vegas or not. Yet in the end all that matters for now is that he win because if he were to lose in his American debut what would follow is obvious to his loyal trainer.

“To make a living in boxing you have to come to America,’’ Khanyile said. “You cannot box in South Africa and be assured you’ll be made for life. Thomas is fortunate. The goldfields of South Africa have given him a sponsor. They give him six weeks off to prepare for a fight. But he must keep winning. It makes life easier.’’

So would a win over Cruz (35-11-1, 23 KO) because it would move Mashaba (20-1-4, 12 KO) closer to a more widely regarded world title like the one held now by IBF champion Robert Guerrero or WBA champion Chris John. Because he is ranked higher by the IBF (4th) than the WBA (6th), Mashaba has his eyes on Guerrero, although his real goal remains Las Vegas, a city that has become a symbol to him of a life far different from the one he has known or the one he dreams of for his three-year-old son, Tshuvelo.

That dream began when Mashaba was 17 and walked into a local gym for the first time. No one else in his family had ever boxed so there was no past history to fall back on, no one to seek out for guidance. There were only TV images of the great American fighters in Las Vegas and his sense that his hands were made for something more than holding a shovel.

“No one in my family has been a boxer,’’ Mashaba said. “Only me. It’s my dream. My mother wanted to stop me but my father said ‘Let him go to box.’ Only when I fought for the South African title did my mother go to watch.  Mostly I went alone but I liked it from the first day. It was in my heart.’’

Not even his only loss, a split decision to former world title contender Sod Looknongyangtoy in Thailand nearly five years ago, dissuaded him and now he is finally here, 12,000 miles from home but 10,000 miles closer to a dream than he’s ever been before.

“I don’t know much about Cruz except that I will beat him,’’ Mashaba said. ‘What choice do I have?’’

None if he plans to one day fight in a city where so many people believe the streets are paved with the gold. Gold that Thomas Mashaba pulls from the ground every day in South Africa.